Does charging your EV to 100% damage the battery? | Plug Life Television Episode 4

[@EV-olution]

I can't believe that I had not seen this in the past. This is a fantastic video and I will mention it in one of my upcoming videos because your explanation is clear, precise, and it avoids me having to make one 🙂 Thank you.

[@martinconlon2673]

Thank you for taking the time to post this kind of information. My first EV is being delivered next month and I'm trying to gain as much knowledge as I can in preparation from moving from ICE to BEV. This is exactly the kind of information which will help me. Keep up the good work :-)

[@tonybkent]

As a very new PHEV driver with (free) work and (soon) home destination charging, a 24 miles round trip commute a few times a week and a 36 miles battery range, I found this video incredibly helpful. Great work.

[@PlugLifeTelevision]

Many thanks. Happy driving! You'll probably find that your work colleagues will start buying EVs and PHEVs off the back of your success, so make sure you set up a rota to make sure that everyone gets to use the charge points for as long as they need. My colleagues have morning and afternoon shifts on the workplace charge points, occasionally squeezing in a third swapover if needs be.

[@rachelletilsley1296]

Thank you so much Dr McTurk. I've only just managed to review this. Just yesterday we had yet another discussion thread in NZ about this topic. I wish I'd seen your response before then. This is excellent for those of us that aren't scientists to explain in very plain English a quite technical topic.

[@PlugLifeTelevision]

Thanks Rachelle! I recall you mentioning previously that EV drivers in NZ had been worried about charging to "100%" as stated on the dashboard. If the battery management system in EVs actually charged the cells in the pack to their real-world 100% State of Charge, I'd agree with them, but all EVs have that upper SOC buffer that significantly reduces degradation, so there's little reason to worry. In the case of the LEAF, the cut-off shaves a mere 0.05 volts or so off of the cells' maximum voltage, but even that's enough to make a big difference on cycle life whilst not sacrificing too much range. If some drivers still like to keep Long Life Mode engaged on their EVs (such as the 80% limit on 24 kWh LEAFs), then that's fair enough, since in theory the bigger the upper SOC buffer is, the more cycles you'll get out of the cell. However, since the graph of voltage vs discharge capacity for a fully charged Li-ion cell quickly tapers off from a steep-ish drop to a far more shallow gradient, we quickly reach a point where taking a few millivolts off of the charging limit starts to eat into range more than it does near the maximum voltage of the cell; the same applies towards the cell's minimum voltage, too. A well-designed battery management system will have already factored in cell degradation at high voltages and set the "100%" cut-off voltage accordingly, meaning that the car's pack should have a significantly increased cycle life vs letting the cells reach their true maximum voltage (which the car won't allow anyway) without locking away too much of the battery's usable capacity. Tesla are more transparent about this, and as such don't offer a "Long Life Mode," but do offer a "Range Mode," whereby the cells are charged to a higher voltage in order to extract more range from the pack. This is accompanied by a disclaimer to the user that there will be an impact on battery life if it is done regularly. As far as I'm aware, Tesla are the only manufacturer who do it this way around. I wouldn't recommend using "Range Mode" on a Tesla (i.e. going from a sensible voltage cut-off to a more aggressive voltage cut-off) unless absolutely necessary, but on the flip side of the coin I wouldn't bother too much about "Long Life Mode" on a 24 kWh LEAF (i.e. going from a sensible voltage cut-off to a very conservative one).

[@NicolasRaimo]

THANK YOU for doing this video Euan you saved me making a video about same subject that i kept getting asked to do, well done on another GREAT video

[@CrashUK28]

Great video.

[@EdCranium]

At last an explanation in the form of an easily understandable graph. Thanks.

[@funkylovetank]

Does the '100% is good practice' advice apply equally to older battery technology? I have a 2016 Nissan Leaf just arrived from Japan and wondering what to do - 100% or 80% (which everyone seems to be advising) charge limits. cheers!

[@privettoli]

This video is 5y old but in the US there's still a lot of places where you'd need 100% on vehicles like ID.4 or you won't make it to the next fast charging station.

[@a88888888a]

I have a family member that has a 2018 leaf. They top up to 100 percent nightly and only get down to about 76 percent on their daily travel route. Based on your video should I have them charge up to 80~90 percent and then drop down to 30 percent over a two day period (& only top up to 100 percent every 10 days)? The only issue is that they use a 1.4kw level 1 charger... So they are concerned if they ever have an emergency trip that requires more range. Thanks in advance!

[@DrCajetanTellis]

You say that balancing happens at full charge of 100 SoC . However if there is a buffer os five or ten percent , the balancing will never happen , because none of the batteries are fully charged . Please explain

[@markedwards3568]

Thank you for this video. Clear and extremely useful info on how and when to charge our new ev.

[@PlugLifeTelevision]

Thank you! I should add that if the vehicle is parked up for a long time, e.g. if you're away on holiday, aim to store it at between 50 - 80% SOC. See the episode about looking after your EV during the COVID lockdown for more info.

[@JonathanPorterfield]

Brilliant Euan ! Any thoughts on excellant SOH on 6.6 leaf ? All the ones ive had seem to be lasting better on soc than 3.3 ?

[@PlugLifeTelevision]

Yeah that's an interesting one since the general consensus was that slower charging would help to preserve SOH. As we've seen with successive rapid charges, the LEAF's SOH software seems to respond well to faster charging rates, and is also susceptible to the seasons, so I'd take it with a pinch of salt. If the real-world range of 3.3 LEAFs is noticeably different to the SOH of 6.6 LEAFs of similar age and mileage, then there will be other factors at play, but I think it's just the way that the BMS software has been written.

[@MarkAtkin]

I have a 30kWh Leaf with a 3.3kW charger. Is the difference between the 3.3 and the 6.6 enough to worry about?

[@JonathanPorterfield]

Mark Atkin no ! Just give you leaf a good mixed diet of granny cable, level 2 and rapid charges.

[@CrashUK28]

Does any of this help the battery.

[@NicolasRaimo]

John is it possible the ones with LOW SOH need the BMS update to software that calculates the SOH? Nissan i believe have started updating cars now

[@ivoabreu8935]

Hi Dr. I would like to hear your opinion about my 24kwh leaf charges. It is best to charge slowly in a warm garage for several hours, ending charging with cell temperatures of 28° C(90-95%SOC) or letting the car stay overnight on the street and do a quick charge early in the morning? During the night the temperature are fresh (15°c) and after a 30-minutes quick charge the temperature cells never reach 28C° that I have in the slow charging at home garage. Furthermore, doing the quick charge I am reducing the time that cells spend at high voltages (4.1V or more).

[@alandimery3379]

Very good. That was well explained. Thank you. Does this all ring true with bigger batteries as well? Such as in my 64kWh Kona Electric?

[@PlugLifeTelevision]

Absolutely: the cells in high capacity battery packs charge and discharge at the same time, just like in a small battery pack, so it's not like you're charging some cells before others just because the pack is bigger. However, because the pack has a higher capacity, less of its SOC is used to cover the same distance than in, say, a 24 kWh Nissan LEAF. This places extra emphasis on not plugging the car in every time you drive 5 miles down the road to the shops; the cells will degrade if kept at at high SOC for a prolonged period of time. If you have a high capacity battery pack and only do short journeys, only plug in once the battery is between 20% and 50% SOC, and feel free to charge it to anywhere between 80% and 100% SOC that's convenient for you. Remember to fully charge and balance every so often to calibrate the BMS and bring all of the cells back in line with each other.

[@thesmallrougeone]

Great reassurance. In my two weeks of Leaf ownership I've routinely charged to 90-100% - more recently 95% by limiting the charge time. I run it down to 30-40% which isn't quite enough to do my daily return trip do I'm charging every night. Good to know that I can charge to 100% without doing damage, although I live at the top of a big hill so the brakes get a bit more of a workout when I'm above 95%!

[@PlugLifeTelevision]

In that case I'd leave a bit of a margin purely so you can maximise regen and minimise brake wear, charging to 100% about once a week to balance the pack. I remember when I had my 106 Electric retrofitted to Li-ion and forgot to leave an upper SOC buffer when the BMS was programmed. I also lived at the top of a steep hill, and on the car's first journey out of the house from fully charged, every time I took my foot off the throttle, the maximum voltage warning light came on. That was a worrying quarter of a mile or so until I could finally get the car onto some flat land and burn off some electrons! Of course, that issue would never happen with a modern EV, which has already factored in an upper SOC buffer.

[@plaw9999]

Stupid question time. At what power level does the battery balancing begin? I currently charge at work (3.5KW) - and at home on ZAPPI (7Kw max but often on eco ~1.5Kw). Do I need to use granny cable for balancing or does it kick in near 100% at higher rates of charging ?

[@grahamcastle8189]

Thank you, Euan, clear, concise and very useful to me as a new EV owner. Why don't they tell you this in the car manual?

[@shaunwalsh6354]

Very informative, but can I ask, does this apply to the NMC type batteries? I have just purchased an MG4 long range Trophy model and am being told to keep the charge between 30% and 80% for this model with the long range NMC battery chemistry and only do a balance charge to 100% once a month? I purchase on a PCP over 4 years and the MG has a 7 year warranty, so does it mater if I charge to 100% on a regular basis?

[@manwithcorsae7738]

Brilliant video. Thanks very much. Things looking good north of the border.

[@tonybooth8755]

Wow! So interesting. The bit about the batteries that is!

[@roundel52]

A brilliant video with excellent graphics. Thanks for doing this!

[@EVoLutionAutoDrivingSchool]

Does the same principle apply to Tesla batteries? Do they still use a buffer? They advise to charge to 90% and only to 100% if you NEED the range. If they don't employ a buffer, how would the advice change and how would the packs get balanced?

[@PlugLifeTelevision]

Tesla are the exception in that they allow access to a true 100% State of Charge. I'd advocate charging a Tesla to 80% for daily use and 90% for longer journeys. I'd also fully charge and balance the pack to 100% once every couple of months, or when full range is absolutely needed.

[@gronkjor]

Great video. I have a MINI Cooper SE (BMW I3 tech). I get that we shouldn't leave the car at a 100% for a long time, but I can't quite figure out what a long time is. Would a few hours in the morning several times a week be bad? Thanks again for a great video. Rasmus

[@PlugLifeTelevision]

Thanks! A few hours at 100% is fine; that's what I did with my LEAF. I'd try to avoid leaving it at 100% for periods of a week or more, especially on a regular basis.

[@EVSA]

Try and only charge to 100% if you are planning to do a long trip the next day, otherwise only charge to about 80%. Your battery pack will last a lot longer if you do this...

[@flyboybeetson]

Your video has convinced me to bite the bullet and switch to a Nissan Leaf 2019. It will be replacing my Citroen DS3 1.6 turbo diesel!

[@PlugLifeTelevision]

Great to hear that Karl - welcome to the club!

[@theophiluslamptey47]

Wonderful decision

[@willgeorge5644]

In NZ, this would be true if it was 95%, but it's 80%! In northland there are not many chargers and at one place, Kawakawa there is only one charger limited to 80%. I have arrived at the next station late on a rainy Sunday night with 1% because the previous one was limited to 80%. I told chargenet, they don't care.

[@pt6423]

An intelligent and an informative channel this is. Well done.

[@jeffjsmith]

Very useful and informative video Euan - thanks! A quick question, if I have to leave my EV used for a month, what is a good charge level to leave it at, or should I leave it plugged in to the homecharger?

[@PlugLifeTelevision]

Thanks Jeff! When leaving your car for a prolonged period of time, try to leave the battery at around 80% SOC to minimise degradation. Teslas have quite high parasitic drain from their electronics, so if your EV is a Tesla, I'd recommend setting the charge limit to about 80% and leaving it plugged in whilst you're away.

[@jeffjsmith]

@@PlugLifeTelevision Thanks for the clear reply. We will be getting the 2020 Zoe in April, the one with the 52kWh battery. We do have a home charger installed and I will investigate charging options when we get the car. Can't wait! Thanks for the channel Euan, really useful stuff!

[@richardcresswell7096]

Hi there love all your video just the right speed and level of understanding for me. converting a Honda Insight Gen 1 at the moment and the battery is going to be a series of 18650 modules. somewhere around 2500 cells total. Is the single wire Bms you mention something I should be looking at? Looked at Dukosi site but wasn't sure if its still in development or just for the big boys ie proper EV manufacturers

[@wladimirjordanov1476]

Hi there, I have , maybe this strange question. I’m a owner of a Nissan env 200, from 2014. My questions is , is her possible to swoop de battery pack for a 40kw one and would be prijs ?

[@PlugLifeTelevision]

Good question! Nissan are one of the few EV manufacturers who have made it difficult to upgrade battery packs in their EVs because the configuration of the modules, and the connectors to the Battery Management System, are different in the higher capacity packs. I know that the 24 kWh LEAF cannot be upgraded and I am fairly certain that the same applies to the 24 kWh e-NV200. For a more thorough explanation, I cover this in Episode 1.

[@MrJosteinSand]

@@PlugLifeTelevision Hi, Just a comment on that. The 24 kWh leaf can at least be upgraded to 30 kWh ( maybe not the case for 1st gen Leaf) . All you have to do is change the vcm at the same time so that the vcm and the 30 kWh battery is matching. I have done this myself on a 2014 leaf. Don't know about the e-nv200 and don't know if it will work with the new 40 kWh pack. Another option would be to intercept communication from the battery to the vcm and do the mapping so that the vcm thinks it's talking to original battery. Little harder to do but has also been done ( not by me)

[@giubaca]

Nice video and explanation. I discharge my car to as low as i can 7 times out of 10. My observations on LEAFspy indicate that balancing is carried out all the time and will only be stopped when my car is like 3-4% remaining battery, or around 11% reported on LEAFspy. I can show you printscreens from evenings when i get home with let's say 20% unbalanced 200-300mv and after a couple of hours pass or so my battery will get almost perfectly ballanced to 8-9mv. So i still claim that balancing on a LEAF is done regardless of SOC, and the last bit of charging from 99% to 100% is not balancing as generally believed is just pure simple charging.

[@PlugLifeTelevision]

The occasional discharge to as low as you can go helps the BMS to recalculate the capacity of the pack, but otherwise it's good practice to only charge below 20% when needs be in order to maximise battery lifespan. The voltage profile of Li-ion cells is nonlinear, which goes some way to explaining why the discrepancy in cell voltages bunches up to around 8-9 mV towards higher SOC. However, the balancing procedure is only truly completed when the car has stopped drawing power from the charge point of its own free will (and not because of a charging timer.) The charging profile is CCCV - Constant Current followed by Constant Voltage. In other words, the car will draw the maximum charging current possible from the charge point until the first cell voltage hits Vmax, at which point it holds the cell voltage at Vmax by throttling back the current, tapering it off to a specified minimum value, e.g. C/50 (i.e. a current that would take 50 hours to charge the cell from empty if applied continuously). It's that CV part that helps to bring all of the cells into true balance. That said, if the cells in your LEAF's pack are genuinely rising and falling within 8-9 mV of each other at mid-to-high SOCs without balancing, your pack is in excellent condition.

[@DannyMaas]

Haha, The scotland part was funny! The rest is also great! Keep up to good work!

[@cristiant4030]

Great video. I am new 24 Kw 2015 leafer ...was wondering if after charging at work to 100% and consuming only 8 or 10% when reaching home is an issue?in other words does 90% percent until next morning counts as leaving it at high state of charge just too long? Thanks

[@PlugLifeTelevision]

Glad you liked it! Leaving a 24kWh LEAF at 90% overnight isn't an issue. However, if you're going from 100% to 90% on the home leg of your commute, does that mean that you're arriving back at work on 80% and plugging in? This video was designed with the 24kWh LEAF in mind, but using considerably more of its battery during the daily commute. Therefore, for your short commute, I'd run the car down quite a bit more (50 - 20%) before plugging in, unless you need the range for a long journey. In fact, since the 24kWh LEAF has Long Life Mode, which cuts off charging at 80%, and since your commute is quite short, I'd put on Long Life Mode. Then I'd fully charge and balance the car to 100% about once every couple of weeks to keep all the cells balanced, ideally timing your full charge and balance to finish within a few hours of you next driving the car. All of this will minimise degradation and maximise lifespan.

[@cristiant4030]

@@PlugLifeTelevision perfect that makes now sense... I would ussualy plug it in at 30% ( never at 80%) but I always went to 100 % that's why I had my doubts.I would from now on charge it on Fridays to 100% as its our weekend car and get low by Sunday. Thanks for you reply.

[@jestronixhanderson9898]

Ah this works well for me, my 6 year old leaf has 85% SOH still, I used to do 80% and down to 40% every day, however I now do 100 to 60%, I have it timed so it hits 100% about an hour before I head off to work. Great thing is the car has a bit more punch and allows me to do an errand or two should I need the extra %. Full balance charge daily :) I only charge at 1.2kw aswell , nice and gentle. Hope to get another 5 years out of it.

[@plaw9999]

great video. Any chance of a link to the charging initiatives?

[@CrashUK28]

I like how it rubs it in at the end of video

[@rossmc40]

Good to dispel the 100% myth as this was one I was concerned about when I got my first EV

[@roberthaggas8164]

That was a very interesting video, and I fully understand and agree with everything that you say. However, the extra time spent charging to 90 or even 100% has to be offset against the potential of arriving at your next stop and finding all chargers either occupied or out of service.

[@maureencooper6644]

Brilliant video! Extremely helpful thank you

[@kelalamusic9258]

Thank you so much for this video. I just purchased a new Leaf, and I’m concerned about overcharging. I will most likely charge over night. When it reaches 100%, is it OK to leave it trickle charging? Thanks again.

[@PlugLifeTelevision]

Whilst it's technically fine to leave the car plugged in when it reaches 100% as the car will automatically stop charging when it is full, it is advisable not to leave the car fully charged for days or weeks on end as this will cause accelerated battery degradation vs leaving it at, say, 80%. For an original 24 kWh LEAF doing a 50 mile round trip commute every day (like my old car), daily charging to 100% is fine because the car is driven a few hours after completing the charge. However, for new higher capacity EV batteries that use less of their capacity to complete the same length of journey, or cars that are used infrequently, try to time a 100% charge to finish shortly before driving it to maximise battery lifespan.

[@kelalamusic9258]

@@PlugLifeTelevision thank you very much!

[@ColinPreston]

New EV user, found your video interesting but I have a question, based on the situation that I have solar panels. I've tended to plug in the car every day that we've some solar generation. This means that between 20 and 80% SoC, the battery is getting many charges of between 1.4kWh and 3.4 kWh that is just topping up the miles available when the car is just sitting at home. For instance today I drove 40 miles, when the battery was at 50%, when I came home the battery was at 35%. I plugged in and a few hours later it's at 43% having added 4.7 kWh for free. I've seldom used rapid chargers and have only charged to 100% a couple of times in 2 months. Am I prolonging battery life or doing the opposite? The car by the way is a Skoda Enyaq 60.

[@PlugLifeTelevision]

Good question! "Shallow cycling" like can have a negative impact on battery health in two scenarios: 1) The shallow cycling is between 80 - 100% SOC, this feeding electrolyte degradation against the cathode (positive electrode) when the cathode is at high potential (N.B. not applicable to EVs with LFP batteries like the Tesla Model 3 SR+, since LFP's potential when fully charged is lower than the degradation onset potential of the electrolyte). 2) The shallow cycling takes place over a "phase change" (change in the physical structure) of an electrode, leading to frequent physical expansion and contraction that eventually cracks and wears out the cell. Modern Li-ion cells are far more resilient to this than older cells. For what it's worth, I top up my EV from my solar panels in short-ish bursts, and for the use case that you've described, your battery should be fine. Also note that the above video was made in the era of short-range EVs and regular commuting, vs big battery EVs and flexible home working today. I now have a Tesla with an 85 kWh battery which isn't driven daily like my old LEAF was. I charge the Tesla to about 80-90% most of the time, and to 100% when I need the range for a long road trip (or once every couple of months to calibrate the BMS).

[@RITB300]

I normally run my Leaf 40kw between 70% and 100%, charging daily. So I take it as this is nearly the same as going from 80% to 100% it's not good for the battery. Would I be better only charging every few days and going from 40% to 100%?

[@PlugLifeTelevision]

I'd say so, yes. The only times it would make sense for you to plug the car in when it's at 70% are if you need more range for a longer journey the next day, or if you get a vehicle-to-grid charger and use it to power your house in the evening, with the car then being topped up with off-peak electricity overnight. If it was me, I'd run the car between 40% and 100%, which on a 40kWh LEAF still leaves you with plenty of range in reserve.

[@CrashUK28]

Love the videos. Tell me this does driving the car hard bad for the battery or should we drive slower in-order to make the battery last longer.

[@PlugLifeTelevision]

Many thanks! As with an internal combustion engine, driving an EV hard will degrade its components faster. The batteries will have to supply more energy in a shorter space of time, meaning that they get hotter, and because more energy is wasted as heat, and more energy is spent fighting drag at higher speeds, the range that you can get from a full charge will be less than if the car is driven carefully. That's not to say that you need to be a Sunday driver all the time, but if you drive like a boy racer, your car won't last as long. Having said that, the battery packs in Formula E cars manage to survive an entire season, and the Li-ion cell chemistry that they use in them is fairly standard in comparison to the average EV on the road.

[@RZOCUK]

In terms of likes of Zoe the real size of like a 22kw is 26kw so the pack will never be 100% anyway :) we charge to 100% of a 22kw pack not the 26kw true pack.

[@MarkAtkin]

Yes Renault and Hyundai are a bit more honest than Nissan, quoting the usable capacity.

[@xchopp]

Thanks. I wonder if e-Golf is the same? We always change to 100% but the capacity has not really suffered much over 4 years and more than 20,000 miles.

[@mombasadele479]

Great video. Question: I bought a new EV 45 days ago, and I've driven it about 1000 km now, always staying between 20-80%. Is it time for a top-up to 100% now? How many kilometers between each balancing?

[@PlugLifeTelevision]

Thank you! Yes, I'd say that you're due a balancing and calibration charge to 100% now. Aim for about once every couple of months for a modern EV.

[@daveiwhittle]

Very informative thank you although now with cars with flatter charge curves such as the etron which I have the charge rate at say 90% is still very fast

[@KiltedJock1]

Had my EV 3 days and this video single handedly settled my concern with EVs and range issues, as of April 2023 slightly disappointed in the total number on rapid chargers available, look at charge place scotland fife and filter ccs 50kw and its disgustingly low, yes I can pay 75 pence at instavolt... but cmon... These last 2 years EVs have exploded

[@jeffjsmith]

Euan, it would be interesting to hear your thoughts on vehicle-to-grid V2G installations and how battery life might be impacted?

[@PlugLifeTelevision]

My old colleagues from WMG did a 2 year study on the impact of V2G on electric vehicle battery life. They simulated EV drive cycles by day and V2G cycles by night, in simulated climates ranging from Alaska to Egypt, and found that V2G improves the lifespan of the battery pack by about 10%. It may seem paradoxical to suggest that more work equals better lifespan, but it makes sense for a couple of reasons: 1) V2G cycling is far less strenuous on the battery than when it is powering an EV, because V2G entails fairly constant power draw, at low power, vs the far more dynamic power profile of driving an EV (sharp acceleration, regenerative braking etc). 2) The battery isn't kept at 100% for prolonged periods of time. If a car is used as a short-distance runabout, usually driven short distances and then left plugged in to charge to 100% for a period of several days before being used again, this makes a considerable difference to battery lifespan.

[@jeffjsmith]

@@PlugLifeTelevision Thanks, that is really surprising and interesting. If you get a chance to do a video on this, that would open a lot of eyes to the possibilities in the future for this I think. Of course you would need the right car and electricity supplier I suppose to make it a real situation. I saw that Robert on Fully Charged has a plan to cover this too in the near future. I am sometime soon (hopefully) taking delivery of a new Zoe and I suspect that won't be V2G-ready, but perhaps they will make available a modification to enable it at some point in the car's life. Thanks again, Jeff

[@PlugLifeTelevision]

@@jeffjsmith Thanks Jeff, it's hopefully a topic that I'll get time to cover in the future, especially once more V2G-enabled chargers and EVs hit the market. At the moment, CHAdeMO is the best equipped for V2G, although I did hear about a V2G trial with Mk1 Zoes. If you're getting a new 50 kWh Zoe, make sure you go for the CCS charging option. Not only is this more likely to be compatible with V2G projects in the future, and twice as fast as the car's onboard 22 kW AC charger, but it opens up access to more rapid chargers that are DC only, such as InstaVolt.

[@jeffjsmith]

@@PlugLifeTelevision Yes, I ordered the CCS option - the car might even be delivered soon, although who knows these days. Best regards, Jeff

[@FancyaBevMate]

Hi there! I will be doing a ten thousand mile back to back test on this and report my findings on the SOH. I charged to 100% for the first 10k in my 2018 leaf and since that point I'm charging to 80-90% for this current 10k (nearly on 15k so far) I have my baseline figures for the first 10k but even if the first 10k isn't relevant I'll use the next 10k charging to 100% from 20k to 30k and see if the degradation changes. Cheers for the video mate

[@PlugLifeTelevision]

That's an interesting study you're undertaking. I'd be keen to see the results of it. 80-90% helps to preserve SOH in theory, but charging to 100% balances the pack. Degradation is one thing, but when stopping charging at 80-90% you'll notice a considerable reduction in charging times when rapid charging and also as thesmallrougeone pointed out above, you'll get more regen from the off once you've unplugged than you will if you charge to 100%.

[@gifted773]

That's an interesting test, have you completed the second 10k miles yet?

[@donscott1764]

@@PlugLifeTelevision Thanks for the great information in you videos and your willingness to fill in more information in this section. I bought a used 2014 Leaf SL odo 30,000 km 19 months ago and have put some 18,000 km on it. I still have 12 bars and Leaf Spy tells me I my SOC when 100% charged is about 88, not down much since I bought it. I primarily charge it overnight on a std. North American 120v 15 AMP 3 prong plug (in North American we call that L1) using the EVSE that came with the Leaf which charges it to 100%. Once or twice a week I'll also plug into a 220v 20, 32 or 50 AMP public charger and usually take it to near 100%. My question to you is: Will the cells rebalance at the L1 120v charge or does it require a L2 220 charge to rebalance? A dealer who discourages use of L1 (and who sells L2 home chargers) claims that the batteries will not re-balance at the 120v std. plug. I've checked with several electrical engineers and they all say that charging with L1 will not hurt the battery and may even be good for it as there is much less heat generated in the battery - heat being the biggest enemy of the battery. I live in coastal BC, Canada so we don't have to worry about many hot days in any case. Would appreciate your input into this discussion. Thanks in advance. Don S.

[@SteveJulien]

Brilliant video, thanks!

[@BillEvans1956]

Hi Euan. Do you have a view on why the new Hyundai IONIQ battery pack charges so much slower than the battery pack on the original IONIQ? There has been a lot of criticism as people see this as a backward step on the part of Hyundai. Thanks.

[@PlugLifeTelevision]

Hi Bill. Rumour has it the new Ioniq has a lower voltage battery pack than the old Ioniq (and most EVs for that matter). The power delivered by a rapid charger is limited by the maximum current that it can provide since P=IV, so it looks like the low voltage of the new Ioniq's pack means that the rapid quickly hits its maximum current and cannot charge the pack any faster. Aside from that, increased battery capacity = increased energy density = more heat dissipated. This is especially true of conventional Li-ion cells since greater energy density = greater internal resistance, so not only do you have a greater capacity of cells, but those cells *could* dissipate more heat for a given C-rate (current with respect to capacity). If Hyundai are still using cabin air to thermally manage the battery pack, then this method may not be quite as fit for purpose as it was with the old Ioniq, meaning that they've had to be conservative with charging speeds and throttle back the charging power quicker than they did with the original Ioniq. The above is entirely speculative, but could give an insight into the slow charging speeds encountered by Bjorn in his test video.

[@BillEvans1956]

@@PlugLifeTelevision Thanks. Apart from that, it looks like a good car to buy. Would battery degradation be more likely in this scenario?

[@xchopp]

5:59 -- Oh crap, that's what we've been doing with our 2016 e-Golf. We just plug it in every time we get home (most of our trips are 2 - 20 miles). On the other hand, after 20,000 miles+ it doesn't seem to have affected the capacity at all: is this because when it has completed charging, it isn't really at 100% but more like 80% of the actual total capacity? p.s. we love our e-Golf, not going back to gasoline.

[@PlugLifeTelevision]

I couldn't tell you the size of the e-Golf's upper SOC buffer, but I'm sure it's much less than 20%. Definitely start running the battery down to below 50% before plugging in (where possible), and if charging to 100%, for optimum State of Health, try to time the end of the charge so that the car isn't sat at 100% for more than a few hours before being driven again.

[@iainmackie7064]

I’m a bit confused (nothing new) you say quite clearly at 5:50 that charging to 100%, will balance the pack if done on Destination (AC) chargers, but typically Rapid Charging (DC) won’t. But as AC charging is converted to DC by the car’s charger, and the final 95-100% is super slow, why won’t DC charging balance the pack? I’m struggling to see the difference in the final stages. But this is a great video (series of videos). Learning so much and love it when myths are busted.

[@OKtunes]

I have a related battery question. If I drive 100 miles a day, would a 40 kw hr Leaf battery lifecycle be shorter than a 62 kw hr battery due to more frequent and thorough charge/discharge cycles, or is the lifecycle of a battery ultimately determined by time and heat. I also wonder if a thermally managed EV like a Cooper se with a 32 kWh battery might actually last longer than a Nissan Leaf 40kwhr battery as it can better keep the battery at optimal temp.

[@PlugLifeTelevision]

Typically, higher capacity battery = lower C-rate for a given load ( = less heat dissipation) AND less depth of discharge over a given distance = worked less hard over its lifespan = lasts longer. You make a good point about the LEAF's lack of thermal management, though; if the 40 kWh model is rapid charged regularly, it will get hot and stay hot, and therefore degrade faster than an EV with a thermal management system that can remove that heat during or after rapid charging. Even the 28 kWh Mk1 Ioniq, which just scavenges air from the cabin rather than using redirected air conditioning or liquid cooling, should comfortably outlast a 40 kWh LEAF that doesn't have any form of active thermal management system.

[@OKtunes]

@@PlugLifeTelevision Thanks for the quick reply. That does create the dilemma of the right size battery for the need. I have to admit that the 60kwh Leaf battery with a larger motor makes me nervous at the heat it will generate without thermal management. I am coming off of owning a Bolt, so obviously battery issues and safety/longevity are most important to me. Having a level 2 home smart charger at least allows me to wait to charge until the battery is cooler and prior to leaving.

[@PlugLifeTelevision]

@@OKtunes the larger motor will only generate more heat from the batteries if you floor it; otherwise you'll be pulling roughly the same power as you're driving along. Other cars to consider in roughly the same price category, which have thermal management systems, are the Hyundai Ioniq and Kia e-Niro. I've yet to hear how well the 62 kWh LEAF copes with repeated rapid charging, but the theory is that the battery is so big that the charging C-rate is less, so heat dissipation is decreased (yet to be verified!).

[@OKtunes]

@@PlugLifeTelevision Thanks for the info. I live in a hot climate and my main concern is about battery safety and degradation. I don’t want an LG battery as the issues with the Bolt/Kona have me concerned (this GM buyback has been terrible). I seldom fast charge and usually drive 70 miles a day at most before level 2 charging set to start charging before I leave for the day. I just don’t want a car where the battery is too degraded and needs replaced at 100,000 miles.

[@PlugLifeTelevision]

@@OKtunes Depending on how hot we're talking, the LEAF might not be too keen on its environment, as it will have no way to actively cool the battery at elevated temperatures, even if only driving around town on a very hot day. EVs like the Renault Zoe which redirect air conditioning to the battery to keep it cool, or the e-Niro with its liquid thermal management system, are likely to have much longer-lived batteries than a LEAF. The e-Niro may be similar to the Kona, but the crucial difference is that Kia uses SK Innovation cells, rather than LG Chem, so they're not affected by LG's issues.

[@davegiles5869]

Just an update regarding the Polar rapid chargers as I use this supplier all the time I can confirm the latest chargers start to ramp down on power at 80% SOC sent to the car with a steady drop in charge rate until the battery and car indicate the SOC is 92 to 96% depending on the battery capacity as I have a Leaf 24KwH it stops at 92% and I saw a Leaf 30 shut off the charge at 96% the only vehicle I have seen on this charger go above this % is a BMW i3 and that went to 99% before stopping.

[@PlugLifeTelevision]

That's good to know, and a great bit of common sense from Polar. We don't have many Polar rapids in Scotland due to the success of the largely free-to-use ChargePlace Scotland network, which typically has a 1 hour time limit on the rapid chargers, after which they shut off.

[@watcher24601]

Looking back at your previous episodes. Interesting that you recommend charging to 100% at least once a week. Without home charging I rarely get above 80% unless make a special effort or staying with family. Once every 3 months is more likely, what are the longer term implications of never balancing and usually having 20 to 70% charge?

[@PlugLifeTelevision]

This episode was designed with the short-range EVs of yesteryear in mind, and assumed that they were being regularly used on daily commutes etc. The fact that you run your EV between 20 and 70% is actually perfect for long term battery care, since the chances of electrolyte degradation at high SOC are even further reduced. Depending on how often you use your EV, and your typical annual mileage, a once-per-month charge and balance to 100% is good practice to keep the cells from falling out of balance and to allow the BMS to recalibrate to understand where 100% SOC is in terms of kWh put back into the battery. Once every three months isn't the end of the world, but never balancing will eventually result in some cells falling out of balance, which will result in them reaching lower voltages before the rest of the pack, which in turn will limit the range of the vehicle. This is a very long term process, but one that a full charge and balance helps to delay even further.

[@watcher24601]

Thanks, good to know, drive it most days, about 8k miles a year. I would charge to 100% overnight more often but involves a trip to see family which hasn't been able to happen much this year.

[@alansteventon9370]

We badly need People like yourself to help promote the truth about Electric vehicles. I got a Vauxhall Ampers 2 years ago as a foot in the Electric car driving, I am now waiting for delivery of my Hyundai Ioniq Electric late September so I will be full Electric.

[@FancyaBevMate]

Alan Steventon you'll be BEV Mate ;)

[@PlugLifeTelevision]

An Ioniq EV? I'm jealous! They're without doubt the best EV on the road today in terms of efficiency, charging times and reliability. Don't get me wrong, Teslas are awesome, but Ioniqs are just a tad more affordable. Also the Ampera is one of only two PHEVs that I would recommend, the other being the Kia Optima PHEV (note that the PHEV version of the Ioniq is dreadful in comparison to the EV version). You clearly have a good choice in cars!

[@jameshoyles4261]

Now we have the 64 kWh Hyundai Kona, now that really will shake things up! 300 miles :0) and Utility (Camper mode)

[@pushcreativity]

I asked my local Vauxhall dealer 3 years ago about getting an Ampera but they completely talked me out of it, something about battery cost blah blah, I can't quite remember the excuses. I did get an Ioniq BEV a year ago, SO happy with it, you will not be dissapointed!!

[@baronsilverbaron757]

I have just bought a new Leaf 62 KWH. So just to be clear. If I plug my Leaf into my domestic 240v plug and leave it to 100% it does no harm?

[@PlugLifeTelevision]

Hi! This episode is a couple of years old now and was designed with older, regularly-used, short-range EVs in mind, such as the 24 kWh LEAF. Charging a 62 kWh LEAF to 100% will be fine, but for optimum lifespan I would recommend the following tips for a long-range EV such as yours to maximise the battery's lifespan: 1) Aim to keep the battery between 20% and 80 % State of Charge, unless you need the range. 2) Only charge to 100% if you're planning to drive the car within a few hours of the charge finishing - don't leave it sitting at 100% for several days or weeks. For more information, see episode 15: kzbin.info/www/bejne/iZeoZJWKh8pmrJo 3) Aim to plug in the car if the State of Charge is between 50% and 20% SOC, or if you need more range for your next journey. Routinely shallow cycling the battery, especially between 80% and 100% SOC, will increase the rate of degradation. Going below 20% SOC is fine if you need the range, but doing so routinely accelerates degradation vs keeping the battery in the 20-80% SOC window. 4) Fully charge and balance the car to 100% SOC about once per month if possible. This helps to recalibrate the Battery Management System and reduce uneven degradation of cells. Remember to only do this when you intend to drive the car shortly afterwards, as per 2). 5) If neither your car nor charger have an SOC limiter on them, you can calculate how long you need to keep your car plugged in to reach 80% SOC using the Plug Life Television Lockdown Battery Top-Up Calculator: www.pluglifetelevision.co.uk/lockdown-battery-top-up-calculator All of that said, the robustness and reliability of battery tech is improving all the time, and the upper SOC buffer on EVs ensures that battery degradation at 100% SOC is greatly reduced vs if the cells were charged to their true maximum voltage, as they would be in laptops or smartphones. Chances are that 62 kWh LEAFs that are used as taxis will get battered with constant rapid charging etc, with little thought put towards preserving battery life, and will still manage hundreds of thousands of miles on the original battery pack. However, if you want to look after your car as best as possible, the above advice should hopefully be useful. I would say that point 2), plus the shallow cycling (80-100% SOC) warning from 3), are the most important points to adhere to.

[@baronsilverbaron757]

@@PlugLifeTelevision Brilliant!. Thanks for the detailed info especially the 'top-up' calculator. I probably only use the plug-in charger that goes into a normal 240v socket. So between 50 and 80% it only seems to take a couple of hours.

[@lawrencetaylor4101]

Thanks for these videos.

[@Z-add]

You said you shouldn't use the battery between 80 to 100% SOC. So for daily commute of around 20km i shouldn't home charge my battery everyday. Doing that will keep the battery at high voltage all the time. I should use more of the battery and take it down to 40% or 20% SOC and then charge it to 100%(if home) or 80% (if rapid charging)

[@tomsixsix]

2:45 technically there are some PHEVs which can genuinely use rapid chargers, old Mitsu. Outlander PHEVs for instance had Chademo, and there's a new Mercedes PHEV with a 25kWh battery which can rapid charge at 60kW(!) However, it is true that most on the market are only 3.3kW AC capable...

[@briangriffiths114]

This is a very helpful video as I will be trading in my Twingo GT for either a Fiat 500e or a Zoe as soon as I can. Fiat quotes a battery capacity of 42 kW/h but a useable capacity of 37.3 kW/h so, as my car would always be charged at home as I only do short trips, does it mean that it would never exceed 88% of true battery capacity if I chose to charge it to maximum?

[@paulaxford6754]

I'm unsure why anyone would assume that there's a line of people waiting to use the charger? Not everywhere is in the UK nor is every charger highly utilised.

[@R_Time_Now]

Great video and well explained

[@shin8327]

Enjoyed the vid! Apparently the Mitsubishi Outlander PHEV has Chademo and can rapid charge. It's limited to 15kw but still charges to 80% in about 30 mins like most EVs today - support.fastned.nl/hc/en-gb/articles/205205018-Charging-with-a-Mitsubishi- I've seen the charge rate reported differently in other places but sounds like it does have chademo.

[@PeterLucasathome]

It's taking a similar time to EVs because it has a much smaller battery, i.e. a much smaller "tank" to fill.

[@CandycaneBeyond]

Does this mean that a bolt battery pack lasts longer?

[@anthonycraig274]

I have a 2017 Nissan LEAF 2017, it has a 99.3% battery State Of Health with 20,000 miles. It had 5 rapid charger and 1756 Type 1 charging with a granny charging cable and 2,street slow charge up to 100%.

[@philiponsolent7232]

Really useful for a new ev owner.

[@fontain6674]

Great information!

[@leescott8795]

balancing can be done without charging to 100%. Simply leave your Leaf on overnight, without charging. This leaves to electrical components operational and will balance the cells. If your concerned with battery loss from led dashboard lights, simply reduce the brightness to 0.

[@ThrowThoseCurtains]

I know it's slow and therefore a waste of time but sometimes rapids are not situated near to a destination charger - I have been in circumstances where I have needed 100% charge from a rapid to reach my destination, so a universal 90% cut off would be extremely frustrating (until there are more chargers around the UK and specifically Wales, and then it makes perfect sense)

[@leoclarke6462]

Excellent thank you

[@CrashUK28]

Need to move to Scotland.

[@Sofala]

Another interesting video.

[@vaidulis2415]

Why do they limit max state of charge, and all these lists of having up to 500 cycles charging to 100% while you're getting at least 1000 when charging 20-80? I don't get it.

[@PlugLifeTelevision]

Some rapid chargers will cut off before the cell reaches 100% State of Charge because the charging current has tapered off so much (to prevent the cells going over their maximum voltage) that it's simply not worth anyone's time to continue the rapid charging session. If anyone genuinely needs 100% charge, they can move to an adjacent destination charge point, which at very high SOC will charge the car just as quickly as a rapid charger, thus freeing up the latter for people who need it. The lists that you refer to are probably from cell manufacturers. It is true that a cell that is routinely charged to 100% of the cell manufacturer's stated capacity will degrade faster than one that is charged to 80% of the cell manufacturer's stated capacity. However, the protective upper SOC buffer on EVs ensures that the cell does not ever reach 100% of the cell manufacturer's stated capacity (what the car tells you is "100%" on the dashboard is probably nearer 90-95% in reality). This helps to prevent the electrolyte degrading against the cathode (positive electrode) at high potential, and thus expand the lifespan of the battery pack vs letting the battery charge up to a genuine 100%. That said, as I caution in the video, don't routinely charge your EV to 100%, then drive it 2 miles down the road to the shop and back and plug it back in again. I tend to run the battery down below 50% SOC, and ideally not lower than 20% SOC, before plugging in; of course, if you need the full range of the vehicle to reach your destination, then use it.

[@GavinScrimgeour]

Great video pal 👍🏻

[@alanmonie9729]

You seem a bit anti-PHEV there Euan! The Outlander can rapid charge at around 25kW, so it's much faster to use that than the built-in 3kW charger at a destination charger. It's a shame to say ban PHEVs from rapids. I'd rather have an electric mile than a petrol mile. :-)

[@PlugLifeTelevision]

I was waiting on the first Outlander driver to comment ;) The Outlander is a notable exception in the PHEV world because it can actually rapid charge via CHAdeMO. Admittedly that 25kW soon tapers off because the battery pack is so small, but as long as the Outlander driver stays with their car until they've finished charging and moves it on immediately, then it's fair enough for Outlanders to use rapids (not least because the petrol consumption is so eye-wateringly high that I don't blame you for not wanting to fire up the ICE). As with any rapid charge capable vehicle, sitting on the rapid and waiting for it to charge your car to 100% is a waste of time, but an up-to-80% splash n' dash is sensible. However, all other PHEVs on the UK market today are fitted with a Type 2 socket, can rarely charge above 3.6kW and more often than not aren't supplied with a Type 2 charging cable, and this is where the problem begins. Whereas a CHAdeMO plug is locked in place by the charger, Type 2 plugs are locked in place by the car. Since Type 2 PHEVs can't rapid charge, and many owners don't bother to buy a Type 2 cable to use public destination posts, it is increasingly common to see Type 2 PHEVs abandoned on the tethered Type 2 cable of a rapid charger for several hours at a time, typically drawing 3kW and 5-6kWh max. Even when the car has finished charging and the rapid charger has terminated the charging session, the cable is still locked into the car until the owner returns. This prevents Renault Zoe drivers from getting a much needed rapid charge so that they may continue to their destination. Only yesterday there were reports of an Audi PHEV abandoned all day on the rapid charger at Hermiston park and ride near Edinburgh; the rapid is the only charge point of any description in the vicinity, so any Zoe drivers running low on charge could have been stranded.

[@alanmonie9729]

Yip, I agree with almost everything you've said. I dont think there is any need to physically stay with a car when it's rapid charging. It doesn't make any difference if someone is sitting in the car. EV charging is probably too complicated for many drivers, and I can understand the push to have a universal connector. I'd suggest that rapids stop charging when the power output drops below 7kW ish. That way "most" PHEVs cant charge on a rapid, and it stops EVs from charging up to 100%. We'd have to reexamine that policy regularly in case the economics become such that there is no point installing slower chargers.

[@PlugLifeTelevision]

Good idea about the 7kW cut-off. With Type 2 PHEVs, the limit must be enough to deny a charge straight from the outset, otherwise the driver will walk away and abandon the car all day with the rapid charger cable locked in it, even although the charging session was stopped after only a few minutes. Slower charge points are much cheaper to install, both in terms of the cost of the hardware and of any necessary grid upgrades (or removal of any need to upgrade the grid). Plus, when considering that most slow charging is done at destinations - home, work, shops etc - the driver spends less of their time "charging the car" than they do sitting at a rapid charger - or fuelling a petrol car for that matter - since they simply rock up, plug in and walk away, returning to a fully charged car at their own convenience. Rapids are essential at motorway service stations and along major trunk roads, and for fleet operators like taxis and buses, but with battery capacities getting bigger and ranges getting longer, destination charging via Type 2 will likely remain the most popular form of charging for EVs.

[@chrissscottt]

Interesting thanks.

[@Alex-je6od]

> All EV's have high and low SoC buffers Errr... not all. The Bolt EV has almost no damn buffer which is what made the recall so painful.

[@robberesford4741]

While it's obvious why charging to 100% on a rapid is so antisocial and bad etiquette, can you explain why EV's will only balance on AC, home/destination EVSE's but not DC rapid chargers? I've always understood this to be the case but can't find any explanation why other than assuming that only an EV's OBC (On Board Charger) can balance the cells though still not sure why when with passive balancing at least, the bleed resistors are between cells thus internal to the battery. Please explain as another social media armchair expert is convinced that EV's batteries balance, no matter what they are connected to. Hope you can clarify and explain this. Thanks

[@PlugLifeTelevision]

Great question, and one that I'll need to dig into. However, my understanding is that you're right in that balancing is done by the EV's onboard charger, which only really comes into play during AC charging.

[@timengstrom14]

Why should balancing only happen at 100% SoC? There’s no reason why it couldn’t be done at lower SoCs, and only balancing at 100% limits the time / opportunities for balancing unnecessarily, which makes the dissipation of the heat more difficult to manage.

[@PlugLifeTelevision]

From an electrochemical perspective, there's no reason why cell balancing couldn't happen at whatever SOC the user sets as the maximum charge limit. Unfortunately, most, if not all, EV manufacturers have configured the BMS to only balance at 100%, meaning that if the charge limit is set lower than this, the charging session stops abruptly with no gradual tapering off of current whilst the cells are balanced.

[@insx]

A little confused... You say it's no problem to charge to 100% as they have a buffer but near the end you say not to routinely keep it between 80 and 100%

[@PlugLifeTelevision]

Charging to 100% is fine if you plan to drive the car within a few hours of the charge completing (e.g. overnight ahead of your daily commute). However, if you plan to not use the car for several days or weeks, then leaving the car at 100% SOC is a bad idea because the electrolyte starts to degrade against the cathode (positive electrode) when the cathode is at high potential (N.B. not applicable to EVs with LFP batteries like the Tesla Model 3 SR+, since LFP's potential when fully charged is lower than the degradation onset potential of the electrolyte).

[@imho7250]

I think calling it a myth and then saying it will accelerate degradation will confuse even more people. It’s not a myth that operating a battery between 20%-80% will allow it to last longer than operating it from 5%-100%. Will it “damage” the battery to charge it to 100%? It depends if you consider degradation to be a form of damage. I’ve owned laptops that would allow you to set the charge limit to either 100% or 80%, so that it will last longer. Tesla recommends only charging to 80-90% daily. If the car has passive balance and only balances at 100%, then you will need to balance charge it occasionally. If you need to do it weekly, it seems to already have a mismatched brick in the pack. Clearly Tesla has active balancing, since they sold cars with the battery software locked at 60 kWh and the top 15 kWh was never accessible. Clearly this wouldn’t work with bleed resisters that bleed off anything over 4.20V. So the answer to if you should charge your battery to 100% indicated depends on the battery. The Volt, yes because 100% indicated is 80% actual. The Tesla 75 kWh which is software limited to 60 kWh, yes because 100% indicated is only 80% actual. But most other cars it’s on a case by case basis. So, it’s not really a myth but that you shouldn’t charge to 100% all the time. In your example where someone only drives 20 miles, charges back to 100%, drives 20 miles, charges back to 100%, of course that person should limit the charge to 80%, and only fully charge it prior to a long trip, or once a week.

[@PlugLifeTelevision]

Charging to 100% once a week shouldn't necessarily be treated as gospel, but as I mentioned in the video it does help to keep the pack in good shape by balancing it fairly regularly. The point of doing that is to stop cells, bricks or modules from becoming unbalanced over time, rather than reacting to cells starting to show excessive discrepancies in their voltages after a while. Tesla doesn't necessarily have active balancing. Passive balancing can be performed at whatever cell voltage the BMS desires. Therefore, the software tweak that unlocks the extra 15kWh capacity in a Tesla likely increases the voltage that the balancing takes place, i.e. the voltage at which the bleed resistors are connected across the cells. However, I do agree that Tesla's BMS software is different from other EVs. They seem to have engineered the BMS around "Long Life Mode," i.e. charging up to circa 90% by default, with an override option to take the battery up to 100% if needs be. Most other EVs charge to 100% by default, with some having a Long Life Mode option which charges to a lower SOC, but doesn't necessarily balance the cells (e.g. 24kWh LEAF). In the case of earlier Teslas, follow their advice and stick to the standard charging limit unless you need the range, assuming that it balances the pack at the lower SOC.

[@imho7250]

Plug Life Television, I would assume someone like you would be using Leaf Spy, and not just blindly top balancing the pack without seeing how balanced the pack is near the bottom, or seeing which brick saga the most under acceleration. But for those who don’t use Leaf Spy, then charging to 100% once a week probably won’t hurt. If the BMS uses low budget balancing, it can still track the balance and give the driver a notification that they need to charge to 100% and wait for it to finish balancing. If the Tesla can use software to reset the bleed voltage (which they didn’t), then in theory each time you select 80%, 90%, or 100% then the bleed voltage could be set to the corresponding voltage. But if Tesla did use this method, then it wouldn’t fast charge to 80%. It would slow down to 2kw (or whatever the maximum bleed is) as the brick with the highest voltage reaches setpoint. The newer leaf took away the option to limit charging, so clearly they don’t even want people to try, but it’s sort of ridiculous because you can’t get full regen at 100% (97%) SOC. So not only is it less efficient, it’s trying to charge a fully charged battery at a pretty high current. We know the Bolt has hilltop reserve which limits charging to 90%, but I haven’t seen anyone show the CAN bus data while charging to see if the pack is being balanced at 90% or only when it’s charged to 100%. But as in the Leaf, I would monitor my own battery and only balance it when the bottom balance is out, and the same bricks which are low on the bottom are showing low at the top, indicating they have matching capacity but not matching internal losses. So the real answer to the myth is that it depends on the BMS and what is being reported to the driver. But running the battery from 30%-80% and balancing it anytime there is a 10% imbalance (for batteries that only balance at near full voltage) will allow the battery to last longer. Slow charging to 80% will also make the battery last longer than fast charging to 80%, especially in Tesla. But the Bolt seems to throttle back way before any brick reached 4.2v, and only charges at 1C, so I would expect it to not suffer much degradation.

[@johnbb99]

I think it's a pity you don't emphasise that different cars have different charging and battery management schemes and so you should check with the maker of your particular model what is the best way to look after your car's battery. Isn't it true that if you set a Tesla to charge to 100% it will actually fill the battery to full capacity? (c.f. BMW i3 )

[@PlugLifeTelevision]

In fairness, this video is from a few years ago and had older, shorter range EVs in mind. Teslas are quite unusual in that they allow the user to minimise the upper SOC buffer to extend range. It's not quite 100% of the cell's true capacity, but it's much closer than many of the competition. The key difference is that a Tesla warns you if you've been charging to 100% too much and asks you to set the limit to 90% or less. Since making this video, I've bought a Model S, and I tend to keep the charging SOC limit at around 80% unless I'm going on long journeys and need the range. In contrast, my 24 kWh LEAF was run between 100% and 40% each day on my commute and had no noticeable battery degradation. Another important development since this video was made is that the 30 kWh Nissan LEAF's upper SOC buffer has been shown to be too small. This, combined with some owners routinely leaving their cars plugged in and fully charged at home, even if only driving a couple of miles to the shops and back - so called "shallow cycling" the battery pack - has resulted in higher battery degradation in some low mileage 30 kWh LEAFs, since the high cell voltage at which they are routinely kept results in electrolyte degradation vs the positive electrode. That said, drivers following my explicit advice in the video not to routinely shallow cycle their battery pack (i.e. rarely discharging it below 80% SOC before plugging in again) will see far lower rates of degradation. N.b. most other EVs seem to be surprisingly resilient when it comes to being left plugged in at all times, but shallow cycling should still be avoided.

[@FancyaBevMate]

Hi mate just to let you know (hope you don't mind :) I have put a link to your video on my video I have uploaded) I have finished my first set of tests on charging to less than 100% in my 10,000 to 20,000 miles update on my channel and its looking like your video is accurate. However I will be testing when I reach 10% degradation according to my leaf spy to see if indeed the figures are accurate. Cheers George

[@glideman]

If you’re right why do modern iPhones charge to 80% then wait until you’re almost ready to go before adding the last 20%?

[@KJSvitko]

Try to keep the battery between 20 - 80% for most days. It is OK to go above or below for short periods of time but don't leave the battery at 100% or drain to 5% or less.

[@PlugLifeTelevision]

Spot on. This episode assumes regular use - daily commuting etc - see the COVID lockdown video (episode 15) for advice on long periods of little or no use (pretty much what you've just said!). This video was also inspired by people asking why rapid chargers on some networks cut off at

[@darwincollado8993]

Level 1 charger safe to take to 100% Level 2 charger keep it below 90% Level 3 (fast charger) keep it below 80% Never Drain Battery below 20%

[@countteddy]

not when the next charger is at my limit of range....I,ll take as much as I can thankyou very much...

[@TeeEmNZ]

Ok started believing this till the bit on balancing cells which is just untrue, it actively balances all the time.

[@PlugLifeTelevision]

EVs do not have an active cell balancing system. As described in the video, it is expensive and complex vs a passive balancing system. EVs only switch on their passive balancing system when the first cell reaches 100% SOC during charging. If you're aware of any examples that do differently, post them below.

[@TeeEmNZ]

@@PlugLifeTelevision Nissan Leaf does active balancing. Pretty popular and plenty of then are around and far from high-end.

[@BSAT10]

Moray Council are spoiling the party though with a £3.70 connection charge and then leaving their chargers in disrepair

[@PlugLifeTelevision]

True, Moray are infuriating in their lack of ambition. A £3.70 connection charge coupled with free electricity is actually quite reasonable, working out at a maximum of around 30 pence per kWh to charge a 24 kWh LEAF from 30% to 80% SOC, or just 7 pence per unit to deliver an 80% charge to a 64 kWh Hyundai Kona EV. However, you'd expect the money to be used to ensure that the chargers actually work. Transport Scotland need to be more strict about the maintenance of rapid chargers, penalising any site owners who refuse to do anything about faulty units once the warranty expires. A notorious example is the Rouken Glen Road rapid in East Renfrewshire. The council are denying that it is their responsibility to fix the rapid and saying that you should contact Charge Your Car (actually ChargePlace Scotland - same company, but still, their lack of knowledge is a bit concerning), but ChargePlace Scotland have known about the issues surrounding this unit for months. I bet you that the hold-up in the unit's repair is getting approval from the site owner, which is - drum roll - East Renfrewshire Council. Thankfully there are more proactive local authorities, not least Dundee, who are well and truly on top of their charging infrastructure, expanding it and keeping it in good working order.

[@timjefferson1886]

@@PlugLifeTelevision Ecotricity/Electric Highway need to up their game regarding the maintenance of their rapid chargers; they need to be penalised and/or forcibly removed from services.

[@PlugLifeTelevision]

For anyone who fancies coming along to the EVolution Glasgow EV showcase and test drive event at Riverside Museum on the 6th October, the link to register is here: glasgow.evolutionshow.co.uk/registration

[@ianknight1457]

There's some real bad information in this video. What about Teslas that charge to 4.2v a cell which is 100% of actual SOC as they have no upper buffer. The chargers never balance the pack the BMS does so no mater what charger you use the same happens. I have a Tesla and an Ampera. I would never charge the Tesla to 100% everday as this will ruin the battery but the Ampera I do everday as it has an upper buffer. Tesla has as of a few weeks ago adressed this issue on its older cars because of bad information like this and blocked people from charging to 100%

[@super-sim1665]

Left at 100% would be bad for the battery.

[@PlugLifeTelevision]

Yes, that's something that I should have added in the video - if you're going to leave the car for a long period of time, e.g. going away on holiday for 2 weeks, leave it between say 50% and 80% SOC. Batteries don't like being kept at 100% SOC for long periods of time. Similarly, that's another reason why laptop batteries tend to die so quickly - many of them spend most of their lives plugged in, with the battery being force-fed a trickle charge that keeps it fully charged even although the laptop is being powered from the mains. It's a shame that many modern laptops don't have removable battery packs anymore, since if you've bought your laptop to act as a desktop PC, you could remove the battery pack when you don't need it. However if your EV is your daily commuter like mine is, it's not going to be sitting at 100% SOC for long. Mine finished charging 3 hours ago and will be on the road again within the next hour, likely being run down to 40% before being plugged in again. That's another advantage of vehicle-to-grid technology: even if the car is left plugged in for ages, the battery won't sit at 100% for long before the house starts drawing energy from it. As covered in an earlier episode, WMG did a study on the impact of vehicle-to-grid on battery life and found that batteries enjoy the extra workout. Not sitting at 100% for days on end is one likely reason why that's the case.

[@alanrobinson2229]

Omg We are continually told that 100 percent charge is going to have detrimental effect on battery (even Robert/fully charged). So it NOT true....🤔

[@PlugLifeTelevision]

Well, with the caveat that the car is not left at 100% for days on end and not plugged in every time you nip down to the shops and back. For my old, short range LEAF, I ran it between 100% - 30-40% most of the time. With my new 200+ mile range EV, I typically charge it to 80% and run it down to 20-30%, unless I need the car's full range.

[@alanrobinson2229]

@@PlugLifeTelevision lithium Ion house batteries(solar power) continually charge to 100 percent.

[@PlugLifeTelevision]

@@alanrobinson2229 Presumably with a fairly decent upper SOC buffer though (I'd need to see a reading of the cell voltages to be sure). Plus it's likely that domestic energy storage systems will spend only a few hours max at 100% before being discharged, which helps to improve their lifespan.

[@MiguelRamos-up5tf]

Many drivers want to charge to less than 100% (say 80%) for reasons that have nothing to do with rapid charging. It's not that people don't trust car battery engineers, but people just want to go further and be super careful and prolong the battery life as much as possible. We see on most Li-Ion battery datasheets that the cycle life increases a lot when the charging voltage decreases by a tiny bit. You also read that here batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries and there's the NASA study finding 3.92V as the optimal charging voltage (for the batteries they had then). The Nissan Leaf had the option of charging to 80%. I'm ok with relaxing... But what if you use the car a lot and live in a warmer country... (i live in Portugal, btw)... Is that reasoning no longer valid?

[@PlugLifeTelevision]

The upper SOC buffer set by most car manufacturers is a good balance between minimising degradation by reducing the maximum charge voltage, and not locking away too much of the battery's usable capacity. This is because the graph of voltage vs capacity for Li-ion cells is very steep as it approaches 100% SOC and also as it approaches 0% SOC, and is much less steep in between. Therefore, a small reduction in the maximum charge voltage does not lock away as much usable capacity as the equivalent drop in voltage at, say, 50% SOC. Tesla's engineers used this logic when setting the maximum charge voltage in their cars: "factors affecting cycle life are tied to how the cell is used. In particular: 1. Avoiding very high and very low states of charge. Voltages over 4.15V/cell (about 95 percent state of charge [SOC]) and voltages below 3.00V/cell (about 2 percent SOC) cause more stress on the insides of the cell (both physical and electrical). Avoiding very high charge rates. Charging faster than about C/2 (two hour charge) can reduce the cell’s life. 2. Avoiding charging at temperatures below 0° C. (Our design heats the pack before charging at cold temperatures.) 3. Avoiding very high discharge rates. (Our pack has been designed such that even at maximum discharge rate, the current required from each cell is not excessive.) There is a huge difference in cycle life between a 4.2V/cell charge (defined by the manufacturers as “fully charged”) and a 4.15V/cell charge. 4.15 volts represents a charge of about 95 percent. For this reduction of initial capacity (5 percent), the batteries last a whole lot longer. Unfortunately, further reduction of charge has a much smaller benefit on cycle life. Understanding this trade-off, Tesla Motors has decided to limit the maximum charge of its cells to 4.15 volts, taking an initial 5 percent range hit to maximize lifetime of the pack. We also limit discharge of our battery pack to 3.0V/cell and will shut down the car when the batteries reach this level." Technically, NASA is right in that an even lower maximum charging voltage will prolong cycle life even further. However: 1. Electric vehicle battery packs have proven to be far more robust than many people previously thought, and their default maximum charging voltage has proven to be enough to minimise degradation to the extent that battery packs have surpassed the typical distance driven by a petrol or diesel vehicle before it expires (e.g. "Wizzy" the Nissan LEAF taxi which did 174,000 miles on its original battery pack, with a lot of rapid charging, and is still in regular use, and the Teslas that have driven over 250,000km with

[@endguardianabuse6817]

Why ban plug-in hybrids from using rapid Chargers ? There is no point in it since they can't possibly plug it in the plug is different well maybe in Europe it's not hairy butt in America plug-in hybrid has the same plug as a level 2 you cannot plug a DC fast charger in. But I forget you're in Europe so maybe you can out there

[@ondago2]

In case you're finally this now today in 2024 or recently most easy manufacturers battery companies battery experts will tell you that yes there is a greater sense of degravation and a lithium ion based battery when charged fully to 100% all the things that he stays here are true except for the fact that there isn't a degradation or even damaged it's not an instantaneous damage it is just a greater sense of degradation than would be the case between say 10 and 80% of 20 to 80% that last 20% does take longer charge but it also does cause fracturing of elements inside the electrolyte and it does increase the rate of degradation and therefore shorten the life of the battery.

[@JohnScarrott]

Figure 3 on this page clearly disagrees. I also can see from Leaf Spy that my battery is balancing when charged from 34% to 60%, I can see the shunting of power to and from cells in the Leaf Spy app after I stop the charging. I will continue to charge to 80% and not drop below 20% to get as little degradation as possible, as per this other research. Occaisional 100% charge, not an issue, but do it every time and you'll get the degradation levels shwon in Figure 3. batteryuniversity.com/index.php/learn/article/why_mobile_phone_batteries_do_not_last_as_long_as_an_ev_battery

[@PlugLifeTelevision]

A key sentence from just underneath the Figure: "Batteries tested in a laboratory do not always replicate true life conditions, and the results tend to be better than experienced in field use." From the looks of it, the cells that were charged to 100%, were actually charged to 100%; they didn't have an upper SOC buffer like they would in an EV (i.e. actually charged to, say, 95%, with the dashboard saying 100% for user-friendliness). 80% to 20% regular use is a good strategy to improve the lifespan of the pack, but from my own experience, the upper SOC buffer set by the LEAF is enough to keep the pack in good condition provided that it isn't routinely plugged in despite being at an SOC above 80%. The occasional pack balance at 100% is also important to help keep the cells and modules performing in harmony and to help the BMS keep track of the State of Health of the cells to some extent. I'm intrigued by your observations in LEAF Spy. I'd expect to see voltage relaxation upon charge termination (regardless of SOC), and pairs of paralleled cells balancing each other, but I'd be keen to see the power shunting that you speak of.

[@JohnScarrott]

But the foundation of your claims is that batteries only balance when they reach 100% charge, this is not true of the Nissan Leaf. I charged my Leaf to 80%, I then did several drives in it over a week which would have put the battery well out of balance. Today I put Leaf SPy on the car, powered on and can see the battery has balanced itself after I stopped driving it. The Leaf will balance at the end of any charge, be that from 20 to 30 percent or any other figure. Here is a screenshot from today when I powered the car on i65.tinypic.com/wjavq0.png It is also quite irrelevant. Why? Because as soon as you power the car on, it starts recharging the 12v battery which is powering all of the ancilliaries, and thus within seconds the battery is out of balance again. My second screenshot taken a second or two after power on i64.tinypic.com/2uxzpkl.png And in this shot you can see the 12v battery being charged from the traction battery. The Amps figure on the right is the current going into the 12v. The Volts figure on the left is the voltage of the 12v battery rising as the current goes in. i63.tinypic.com/2cz63b6.png

[@joshuarosen465]

Elon has been emphatic that you should only charge to 90%. There is about a 3 to 1 difference in the battery life between charging to 90% vs 100%. Battery balancing by charging to 100% should only be done a couple of times a year, not every week as you claim. Your advice is wrong when it comes to Tesla's, its fine for a Volt which has a huge buffer because the Volt was designed to go from 0 to 100% everyday, but it's wrong for Tesla's which make much more of the battery available.

[@PlugLifeTelevision]

Teslas are somewhat unique in that they allow the use of a much higher % of the battery's true capacity than most other EVs, so you're correct in that they're the odd one out for this video, which predates most long-range EVs in the UK market (August 2018) and was aimed at the likes of shorter range LEAFs etc that are seeing regular use (hence charge and balance about once per week). I set my Model S - acquired after this video was made - to charge to 80% most of the time, with a full charge and balance to 100% if I need the range or if the battery hasn't been balanced within the last month or two. When charging and balancing to 100%, I try to time the charge so that the car will be driven within a few hours of its completion, rather than leaving it at 100% for days. This would be much less of a concern on an EV with a larger upper SOC buffer, but would still be good practice for maxing the preservation of the State of Health of the battery. Furthermore, Episode 15 (COVID lockdown battery care) covers best practice for what State of Charge to leave an EV at if it's not going to be used for a while.

[@joshuarosen465]

@@PlugLifeTelevision I wasn't aware how old your video was when I posted. I watched it on the Firestick which isn't interactive, it's a TV experience vs a computer experience. Tesla's dominate the EV market especially in the US, we also got the Model 3 much earlier then you did so they are now have almost all of the EV market here. There is a fundamental difference in the way that Tesla is run vs the legacy companies, Tesla is run by engineers who assume that their customers are engineers, the other are run by their lawyers and accountants. I had a Volt for the last four years, just gave it to my sister last week, and I've had a Model 3 since July of last year. As you pointed out the Volt has massive buffers, only 14KWh is available out of 18.4KWh, that's because GM's accountants wanted to make absolutely sure that they never had to do a warranty replacement of the battery. They got what they wanted, my Volt had 0 range loss in the four years that I owned it. Chevy has never had to replace a Volt battery under warranty. GM's lawyers hand can be seen whenever you start the car, to use the infotainment system you have to accept a liability waiver every single time the car starts. Tesla's approach is poles apart. They give you most of the battery to use if you want to and then tell you not to use it all. They are willing to accept the occasional warranty replacement in return for being able to claim longer range. If Tesla has any lawyers they have them chained up in the basement with duct tape over their mouths. Just got the new stop light feature a couple of days ago. Tried it today, it worked on several red lights but it tried to blow through a yellow light. As an engineer I love having beta software to play with and I was happy to submit a bug report on the yellow light. But I could just imagine what GM's lawyers would do if Chevy engineering tried to release something like that, they would take the whole engineering group out into the parking lot and shoot them.

[@PlugLifeTelevision]

@@joshuarosen465 haha, good analogy! Tesla's approach appeals to me as well from an electrochemistry and an engineering perspective. The accessibility to the full range of the battery pack (with warning not to use it all the time), plus the sliding bar SOC cut-off, encourages people to take an interest in how their EV works whilst keeping the process as simple as possible, far moreso than other EVs with more conservative limits or less functionality. Over-the-air updates to add new features to a several-year-old car is a major win as well!