How to check a Hybrid/EV 12V Charging System

[@acerforge3882]

Many thanks for explaining this system so thoroughly. You have answered all of my questions about the 12 volt system on my recently aquired hybrid. Absolutely invaluable information for any Toyota and/or hybrid owner. Your generosity in sharing this knowledge with the wider community is very much appreciated.

[@chanakpugkaing]

You really know how to present these topics! I own a Prius Prime and I’ve truly enjoyed your clear and concise videos. Many thanks for all your hard work, it is greatly appreciated!

[@WeberAuto]

Thank you very much!

[@hanklevi1405]

instablaster.

[@JohnClulow]

This was absolutely super! Thanks so much. We haven't used our 2018 Prime much due to the COVID pandemic and went to start it and the 12V was down. Now, thanks to your video, I know how to check it's viability following a recharge and also how to evaluate the performance of the DC-DC converter should I have to look further into things. One of the best You Tube videos I've seen in terms of clarity of presentation. Well done!

[@WeberAuto]

Thank you very much

[@kturek625]

AGAIN - You are the best at explaining a very complex concept! Having a few multimeters (2-ADC and 1-VDC) shows exactly what is the state of charge and flow. *BRAVO*

[@fernandograca4949]

All the video he present is so detail and crystal clear, which L.A have Professor like him. Thanks for posting You Tube.

[@Diagnosedan]

John in the beginning of your demonstration there was 0.8 Amps going into the 12v battery but there was no current leaving the Dc-Dc convertor. Where was that current coming from?

[@WeberAuto]

That is a good question. I may have bumped the "Zeroing" knob on the clamp. It could also be a capacitor discharging somewhere, maybe the SIR energy reserve capacitor. Thanks for your feedback.

[@dominicfong6341]

I always hit "LIKE" even before finishing your instructional videos.

[@WeberAuto]

Thank you very much!

[@jeffreyherbert91]

You may be surprised and saddened to know that in the uk electric vehicle repair and diagnostics is having a cloak of fear and mystery thrown over it by certain manufacturers and institutes who feel that keeping information such as safe disconnection and isolation procedures a closely guarded secret will make them big money by forcing owners to come to them for even minor repairs.....because electricity is special in their vehicles and not the same as all others....very frustrating!!!! We in the uk look to you to save us professor!!!

[@WeberAuto]

Thank you! I am trying to show my students (and the world) that these vehicles are all basically the same. I will continue to try to take the fear and mystery out of these systems. Have a great day!

[@SuperMarioDiagnostics]

Just saw your motor age article, it would be interesting to see the nvh in action on a diagnosis. But these teachings are way more interesting!

[@WeberAuto]

Thank you! You can see the NVH app in action right here: kzbin.info/www/bejne/qWLGo2aHlrStfbs

[@yousifalzidjali8388]

One of the best, ur explanation is clear and u hide no information thank you a lot I enjoyed all ur videos, they are supposed to be shown at Netflix

[@docstruthers]

GREAT Video! I'm a stickler for correct terminology usage in videos like this and yours was spot on. Excellent presentation and insight. No wonder you're a professor! Thanks for the video

[@compu85]

I have to admit we've used our Fiat 500e several times to jump start diesels with dead batteries. The car has a display which shows 12v load, while cranking the dead car it will show about 2500 watts. The 12v power the 500e can put out is quite impressive - though I'm sure the repair bill from a failed converter would be quite shocking too...

[@WeberAuto]

You have been lucky so far. It would be very expensive for sure. Thanks for the feedback.

[@user-uq7io2os3r]

​@WeberAuto many thanks for all your knowledge and, I'm right assuming so you should be fine replacing weak 12v battery with acid gel bigger (upto 100Ah) battery and then be able to jump started safely other vehicles from rav4 2019 hybrid? As essential jum start is done by 12v battery not converter wich works more like a 100Ah alternator in normal ICE vehicles? If I'm mistaken pls correct me as I'm looking into subject if rav4 hybrid is a good donner vehicle for compact camper like vehicle wich will involve a lot more power drain then standard rav4 45Ah 12v battery can sustain. Many thx in advance for your reply on this matter 👍

[@veejful]

Dear Sir, your vedios are of very informative. I learnt a lot about the EV and Hybrid vehicles. But would you please post more case studies, diagnostic type of vedios. God bless 🙏

[@WeberAuto]

Thanks for your feedback, I will

[@richardmcqueen879]

For an ordinary guy like we with no technical training, I learn so much from your videos. Excellent presentations! Tell me if you will, will this same test work on a 2014 Mazda 3 hybrid? Thanks for your time.

[@Chris-tg7qb]

I own a 2022 Ford Maverick and my accessories battery is giving me issues and Ford is clueless. I would love to know the average voltage of the system when it is in ready mode and then what the average resting voltage of the battery is. They have no clue about this... It would be great if you did a video on this hybrid mini truck because I am sure there are others out there with issues. My ready voltage is 15.24 volts and once I shut down it dives to around 12.54 volts and decreases as it sits. I wish they would just put a new battery in and see if it is faulty. They want to wait and see and I don't like this approach. How does one get this information? Thanks for your amazing knowledge and you are truly a gift for everyone taking your classes.

[@shrilohia]

Excellent step by step and very best explanation to test the said system. Very professional to the point. Great video quality. Thank you.

[@WeberAuto]

Thank you

[@paulfontaine7819]

Thanks for this very instructive video as always. 10:45 explains negative current = current flowing into the battery (= receiving power = charging). How can this happen while the DC/DC convertor is turned off? Where is that current coming from?

[@WeberAuto]

Thank you! Good observation. The inverter has a large smoothing capacitor that is discharging for several seconds or minutes after the power is shut off. That may be where it was coming from.

[@electronicsrepairschool]

Very useful video! But, i still don't get it how the 12v battery get charged with 800mA when the hybrid system its off ?!?1 Don't get me wrong, thats great, i can stick my dash cam with parking mode on and i will never get the 12v battery discharged. But the question is still there, how the 12v battery can get charged with 800mA is the car its off :) Thx for the video

[@toxroma]

Thank you so much mate, I'm from Italy and I've been lucky enough to find this video, I've got a flat battery on my 2014 Yaris Hybrid and I was hoping to find a exhaustive video to check the charging system. I'm so glad that now I can check if is actually working as it should or is just a battery failure. Thanks heaps!!!

[@nishrover]

Thanks Heaps Prof. John Kelley.....Amazing Video with huge amount of Quality Knowledge of the electrical side of this Great Car.... Toyota Prius which I enjoy very much. Watched your video just at the right time before I go to change my 12V Aux battery first time in my 2014 Prius .....So I ll do the same voltage test tomorrow after replacing my new battery just to make sure everything is in good order.....Again great to see qualified people like you spend bit of your time in making these youtube videos which will enormously help to moto users to understand complex Hybrid systems....Cheers & Thumbs Up .....more & more great videos ps

[@tonymai1844]

Wow, so the DC to DC box would work the same on Tesla vehicles. I got the idea now. I was not sure how the 12v circuit charging out put to feed the 12v system. Now I am clear, completely understand why some guy on youtube could hook up the inverter up to 1000W to use and they still did not get any problem in spite of little 12v prius battery. But doing that could wear out the DC2DC box. Thanks Professor Kelly

[@jacklabloom635]

Your videos on these electric cars are really well done. I am learning a lot from these videos.

[@timo5635]

You are a very good teacher. I have watched your video multiple times, and enjoyed it everytime. You know everything! I just checked the voltage on my Rav4 hybrid (2018) and it read 11.7 v. I have not driven it for 2 weeks. It started and I ran it for 5 minutes. Is it time to change the battery? In the past 6 months we had to jumpstart it to get it started, mainly because we dont drive it but about once a month.

[@wenseslao521]

Very nice lesson and you are an awesome teacher thanks for sharing your knowledge

[@WeberAuto]

Thank you!

[@Boom10ful]

Thanks for posting all of these videos! One question, is it safe to connect a battery charger to a hybrid vehicle while the battery is connected to the vehicle?

[@WeberAuto]

Yes, but many 12V batteries in hybrids and electric vehicle are absorbent glass mat (AGM) batteries. They cannot take much current without overheating and getting destroyed. Always use a charger designed for AGM batteries on AGM batteries. Thanks for watching

[@gouveiaclassicos]

Amazing this is just a standard 45h battery in Europe normally know as 063, we have the same problem In Europe finding a side terminal battery for American cars congratulations very good video

[@planet1250]

Hi professor Jhon, i would like to thank you as i've learned so much from your videos. I sincerely appreciate the effort you put in your explanations and your dedication to precision in general. Anyway i hope you realize that you are giving the world an awesome possibility: the access to knowledge ; I'm having some troubles with a doubt however and figured maybe you could help me: what type of scanners work best for newer toyotas? the vcx and tis the are circulating on the internet are not good for vehicles newer then 2015. A big thank you from Italy

[@WeberAuto]

Thank you, see techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_pageLabel=ti_ts_lite&_nfpb=true

[@planet1250]

@@WeberAuto No, THANK YOU

[@dandelay8639]

Great video(s)!! Does the charging system specify the efficiency, what is the energy loss of the DC to DC converter? In addition, does the high voltage charging system specify the energy loss during charging of the high voltage battery? Again, thank you very much for these very interesting and informational videos!

[@WeberAuto]

Thank you! Yes, all of that information can be seen on the Toyota Scan tool. The DC-DC converter creates a lot of heat in the conversion and is liquid cooled.

[@david619dc]

Thank you professor I don't have three voltmeters so I'm going to use my 4 ch Pico scope.

[@WeberAuto]

That would work as well with the current clamps. Thanks for the feedback!

[@LucidNRG]

I am interested to know how many amps of headroom you would recommend for the stereo system. some Prius' and ct200h's have amps and subwoofers stock. i want to know even more about the limits of the DC to DC converter.

[@mohmedsirajkasadiya9367]

Great job explaining to very high level..appreciate thankiyou very much ❤❤❤

[@johnparsons4349]

Does the DC-DC Converter on the Prius Prime have sufficient power to accommodate a high power aftermarket stereo system? Would it handle 1,500 watts from an aftermarket amplifier?

[@shakeelsss]

Thanks for this video and I will see sometimes next year. I should register soon for all 3 phases.

[@paulaxford6754]

Hello, John ... I have been characterising the LDC in my Kona Electric (over OBD2) and it certainly is very similar with an approximate 10 min initial period of constant voltage at (a fairly-high) 14.7 V, followed by maintaining nearly zero current flow in or out of the aux battery for the duration. This is in "Run" mode (same as ready), "Utility" (same as Run but for stationary use), or while charging off AC (and I assume DCFC). I haven't checked what happens after 20 hours of being in any of those modes, however it must have a similar measure. Also, the Kona has a user setting to charge the aux battery every 24 hours if the car sits unused and that is for a duration of 15 minutes. I'm not clear yet on how the IBS and LDC determine the SoC and SoH of the aux battery (and it's a similar size and type to that in the Prius) but I did see what appeared to be a 4 minute load test during a drive that occurred directly after the 10 min charge period. As usual I enjoy your videos ... thanks!

[@SkaBob]

Our Kia Niro PHEV varied the voltage depending on conditions. Driving in the day with minimal load the car only ran the 12V system around 13-13.4V to reduce the draw on the hybrid battery. But switching on the headlights would cause the voltage to jump to 14-14.4V, I'm assuming because it had halogen bulbs and running them at low voltage would make them dim. If it had all LED bulbs then it wouldn't need to increase the voltage since the LED's have their own power power module and only actually need a few volts.

[@francoisgravel8728]

Great video, thank you! @WeberAuto How much amp does the DC-DC converter sends to 12v battery on the RAV4 Hybrid 2019-21 and the RAV4 Prime? I saw someone putting a 2000w inverter on the RAV4 2019 Hybrid directly to the 12v battery (with a 200amp fuse) and I was surprised. Thank you!

[@WeberAuto]

Thank you. I don't understand why some people think that connecting an inverter to a hybrid or electric vehicle will be any different than connecting it to the 12V battery of any other vehicle. As you saw in this video, a properly operating DC-DC converter only sends less than 10A to a fully charged 12V battery. The rest of the DC-DC converter output is there to power the rest of the vehicle's 12V systems and accessories. - The RAV4 hybrid has a liquid cooled DC-DC converter under the inverter. It is rated for a maximum output of 120A. - The RAV4 Prime has an air-cooled remote DC-DC converter under the back seat. It is rated for a maximum output of 150A. As demonstrated in this video, the vehicle's 12V system can easily take 70A to operate with the engine running. A 2000W inverter under a full load will try to draw a maximum of 138A with the vehicle powered on with the DC-DC converter output at 14V. The RAV4 hybrid DC-DC converter is rated for a maximum of 120A; if the vehicle uses 70A, only 50A is available for the 2000W inverter. Obviously, the DC-DC converter cannot supply the remaining 88A of current, so the 12V battery makes up the difference for a while until it goes dead. At most, under full load, a 600W inverter is all that the system can possibly handle without overheating the DC-DC converter or running the 12V battery dead.

[@francoisgravel8728]

@@WeberAuto Thanks a lot for this answer. 150A is what I found in the fuse box, but I wasn't 100% sure it was the maximum output of the DC-DC converter. Few other questions : 1) Does standard ICE car have more powerful DC-DC converter from your experience? 2) The Prime has a more powerful DC-DC with 150A compare to Hybrid 120A but is air-cooled instead of liquid-cooled, is this a disadvantage? What the decision taken to save space? 3) On the RAV4 Prime, I suppose that a 1000w inverter is very safe if you say that 70A is uses for all accessories, right? 80A*14v =1120w. Considering that the inverter will be use in circumstances where car accessories will be off in general (no heater, no defrost, no seat heater, etc.), I could go with 1500w keeping that in mind. Does it makes sense? Thanks again and have a safe day!

[@WeberAuto]

@@francoisgravel8728 1. ICE uses an alternator instead of a DC-DC converter, but they perform the same basic function of supplying power to the vehicle's 12V system while keeping the battery charged. Some are more powerful, some are less. 2. Air-cooled is a potential disadvantage due to the temperature of the air. It will perform better with cool air. The decision to move the DC-DC converter to under the back seat is related to an additional boost converter being added to the bottom of the inverter on the Prime. 3. Yes, that is true, but the DC-DC converter and the inverter you are connecting to the 12V battery were not designed to run at maximum output for hours at a time. They both can overheat and even shut themselves down if that happens. Best wishes.

[@malsyned]

Do you know if the inverter for the 1800W 120V AC outlet in the trunk of the Rav4 Prime XSE with the Premium Package is powered by the DC-DC converter, or directly off of the HV traction battery? Relatedly, do you know if the Premium XSE uses the same DC-DC converter as the base model?

[@francoisgravel8728]

@@malsyned It's 1500w, not 1800w. It is using a DC-DC converter connected directly to the traction battery, only available on Premium package (Techno in Canada). Standard XSE and SE doesn't have this specific DC-DC converter.

[@kens97sto171]

Great explanation on how this system works... Love you channel. So much good information. Thx. Wanted to let you know I have a 2008 Prius and had no issues finding a 12V battery for it at AutoZone.. got an Optimus AGM type. Was $175 I think.

[@WeberAuto]

Thank you! There are auto parts stores that may have a battery that will "fit", but be warned that not all of them have a vent tube attachment. By law, the flammable battery vent gasses must exit the vehicle through that tube going through the floor. If your battery does not have a vent tube connected to it, it is a potentially dangerous situation because the gasses can get into the air inside the passenger compartment. Best wishes!

[@kens97sto171]

WeberAuto The Optima AGM spiral batter did have a vent..

[@WeberAuto]

Good to hear! Thanks for the feedback

[@user-uq7io2os3r]

​@@kens97sto171are you sure about it? As I just fit optima yellow top 100Ah to mine Montero as twin battery split setup a can't recall any tube,vent on that battery..

[@kens97sto171]

@@user-uq7io2os3r My comments from 5 years ago. I have no idea with the availability is on optima batteries currently. Or if quality has changed. The one I originally put in my car lasted just a little bit under the warranty. Keep in mind I was driving the car 50 to 60,000 per year. So a lot more miles were put on that battery then an average person. Second battery that they replaced for free is still working. From what I've heard more recently. Your best bet is to get a battery directly from Toyota. Supposedly the quality is a bit better and it's actually cheaper than most of the aftermarket choices. But that's specifically for the Prius

[@wilbertstakenborg5167]

Thanks i love the Videos,a lot of Toyota Rav4 hybrid 2019-2023 have Problems with the battery and the cosumption or empty battery ,it would-be be Great to make a Video Off this big Problem and i realy Hope that DOCTOR Weber has a Solution

[@toyotatechMDT]

Excellent as always John. Thank you.

[@WeberAuto]

Thank you very much!

[@J87styka]

Как же он здорово всё объясняет

[@caseykittel]

thank you professor Kelly! I love your lessons. I have a question about the 3rd gen plug-in prius. RE: using dc to ac inverter. - I'm trying to hook up an inverter (pure sign wave 12v dc to 120v ac as large as possible) I want to power some stuff in my house if the power goes out. - I plan on keeping the car on in the ready mode while I'm using the inverter. - I am thinking about hooking up to the dc-dc output rather than the battery. I'll install a fuse of course. is this right? seems right considering this is where other high current things are running from. - if I keep all of the aux stuff off (lights, climate, defroster, radio, etc) do you think it would be safe to use an inverter that runs around 1,000w but peaks closer to 1,500? - I would rather use the traction battery using an inverter designed for a solar system. that could power my entire house! thanks!

[@simplyraw1369]

Did you do this? Did it work? Curious is all!

[@caseykittel]

@@simplyraw1369 I bought a refurb ups backup for a computer. Maybe 1,500 watts, but I messed up and got one that is 24 volts. Not sure how to move forward. I already had a 12 volt ups but it’s not a pure sine wave inverter. I don’t trust it. Super crusty square wave. Not even close to a sine wave. I think buying an old inverter for a small solar system would be the best. Hook it to the traction battery. 200+ volts DC in and 120 v AC out. Seems like it would work. Maybe I’ll find one at auction.

[@philh9238]

2 questions for you. How does the engine kicking on charge the high voltage battery? And what would cause the 120 amp fuse to blow for the dc dc converter?

[@retirednongeek7405]

Hello! Great video and explanation. I notice there have been no recent replies, but I am hopeful you or some other viewer can answer my questions. 1.) For a 2nd generation Prius, can the 14.5V DC cable out from the inverter/converter assembly be accessed (for putting on a clamp for a multimeter) without having to remove any of the shrouds, such as at the wipers? Perhaps from below? I can see from the video where the cable exits, but can't see it from above looking at my 2004 Prius. 2.) At the 12V battery, to meter the amps entering or leaving the 12V battery, the metal bracket that connects the fuse block to the positive terminal is very short and very close to the top of the battery. Is this where the clamp for the multimeter needs to be placed, or is there some other way to meter the amperage entering or leaving the 12V battery? And, 3.) when I check to voltage at the jump start terminal and ground under the hood, I am apparently not getting any voltage to charge the 12V battery. My readings are the same as if the car is not powered on, about 12.4 volts. Does this indicate that the DC to DC converter is not working, or could it possibly be a fuse at the fuse block at the 12V battery? Any comments or suggestions on how to further diagnose would be greatly appreciated.

[@jontscott]

Nice video, only point I question is if jump starting with a normal engine/alternator is better or worse than with a nice DC/DC converter setup like this. I have a 05 Escape Hybrid and find it likes to jump start cars as even at idle there is a solid 14 volt output, while my other car with an alternator at idle under higher load will let the voltage sag and struggle. I would expect that in the DC/DC converter design over current has been handled and the DC/DC converter would nicely limit the output current as it approaches the maximum output? Maybe even thermal limiting too so the DC/DC converter protects itself?

[@WeberAuto]

Some DC-DC converters have built-in protection, but others do not. I do know that the owner's manuals of all of these vehicles warn against jump starting other vehicles. Best wishes!

[@ikusha84]

As it's clearly mentioned in this great video, if you decide to jump start other car, just don't forget to switch of the vehicle to isolate battery from DC-DC converter. Other thing to consider is, if these 12V batteries used in hybrid cars are designed to supply cranking currents. I guess they are not...

[@zi4259]

Absolutly great knowledge sir, Good on u. I have a question, what happens if 2020 hybrid corolla is left for a longer period of time and both 12 volt and hybrid batteries run out of charge. Do we have to replace or recharge the 12 volt batter only and start the car, or is there something i am missing. Thank you in advance.

[@sablan02]

Thank you for this video! Great information! Do you happen to have the part numbers for those amp clamps? Thanks in advance

[@aleixbayes1617]

Standing ovation! Thank you.

[@bfarns1001]

Well done John, as always.

[@WeberAuto]

Thank you!

[@asifijaz2105]

Hi. Professor. I. Am. AsIF. Thanks. GoD. U. R. Safe. GOD. Bless u. Now I. Want. Take. Admission. In. You. University so pls give me your contact no. I. Am in New York. Thanks. Give me reply

[@MrJoejewelz]

not adding a competition audio system but i did invest a auxiliary dc to dc converter 20 amp battery charger made by renogy to charge a second agm battery to help power audio system not trying to go past 1100 watts. i have 2021 corolla le hybrid

[@WeberAuto]

Thanks for watching

[@terminationshokv]

Thanks for explaining the system. How much current is the dc-dc converter on the 2021 Toyota Sienna rated for?

[@chinou6037]

Thanks a lot for sharing your knowledge. You really contribue to make this world better living !

[@RaulDukeKnife]

You really are the Hybrid Whisperer. What’s the system trying to protect in the constant voltage mode after 20 straight hours ?

[@electrocar64]

Great video! Thanks MR Kelly

[@WeberAuto]

Thank you!

[@jeffreyherbert91]

Great video.....is there a need to check for ac ripple in these systems?

[@WeberAuto]

Thank you! Good question! The DC-DC converter steps down the higher voltage by converting it to AC, stepping it down through a buck transformer, and then inverting it back to low voltage DC through a rectifier bridge (similar to an alternator's rectifier). To answer your question, I do not know for sure, but I suspect the answer is yes.

[@JohnSmith-ug5ci]

Very educational. Thank you.

[@WeberAuto]

Thank you!

[@michaelyawkal4592]

Tnx a lot prof my appretaion to you to help us is so big big big

[@chrisliberty1773]

Always informative, thanks for a great lesson.

[@WeberAuto]

Thank you!

[@BLR1GBattlemaster]

I've been wondering about this for awhile now. If there is a DC to DC converter that steps down the voltage, why even have a 12V battery? It just takes up a bunch of space and weight.

[@seanlutzi2911]

i have a 2018 honda accord hybrid with a incredible arcing sound from under hood of my car when switching from battery mode to engine(charging mode) comes on. sounds like electrical arcing and its definitely not normal!! also my 12v battery only lasted 2 yrs and was replaced by honda at no charge. but they cant mimic the sound i hear all the time... its really bothersome and after watching this video im sure it has to do with inverter (in back seat) and somewhere on fuse block to 12V battery. its not a good sound at all sounds like my car is about to catch fire or die... any ideas????? dealers just brush me off and think im crazy but wife and kids say trade it in let it be someone else's prob... but i like the car otherwise.... thanks your videos are fantastic... very educational

[@joselitomarquessilva3359]

Muito bom. Aprendo muito com essas dicas. Sensacional

[@WeberAuto]

Thank you very much!

[@christemplett1522]

Clear and precise Thank you

[@matthewweaver1123]

Professor Kelly. I have a 3rd generation prius. I only learned about 2 weeks ago that the Prius has electric supplemental heat. Which has 3, 30 amp fuses. So the supplemental heat can theoretically pull close to 90 amps. Does this exceed what the converter is able to supply while it is in use? Especially considering on the days the supplemental heat is used, the rear defroster is probably also being used. If so would you recommend not using the electric heat?

[@WeberAuto]

The current through the fuses will typically be half of the fuse rating. Yes, the DC-DC converter can handle all of those loads.

[@bilbil2960]

Hi That is a great video i am thankful so much , if u do new epsoid fur us about exactly which part is responsible inside inverter converter assemly i know u did an epsoid but i realy need more more explination ,my best regards

[@dougledbetter6607]

Hello. Will the charging system in a 2018 Avalon hybrid be able to charge 2 auxiliary batteries? Since the original battery is a vented lead acid battery, can I connect a heavier duty AGM battery to it to power an aftermarket stereo?

[@ClockworksOfGL]

The 12v battery on my Volt went bad and the dash lit up like a Christmas tree while turning the car on. It scared me for a minute, but I eventually realized all the error lights were for 12v systems. The moral of the story: if your EV is acting flaky, check the 12v battery! The mechanic counted something like 11 codes, which were all resolved with a new (comically expensive) AGM battery. These cars tend to lean heavily on the their 12v batteries, since the DC-DC converters do not have enough juice to power everything at once.

[@WeberAuto]

Thank you for the information. I will check the DC-DC converter output our two generations of Volts. They should be able to supply more than is needed, but I have never really checked. Have a great day!

[@ClockworksOfGL]

WeberAuto - Thank you for the response, Professor. I think the DC-DC converter on the Volt doesn’t pump out enough amps to power everything at once, but that’s usually a transitory event. It’s also possible that the Volt’s DC-DC converter takes a moment to start outputting amps when you turn the car on (which is why I couldn’t get my car started with a bad 12v battery). I think it’s the former, honestly; some Volt owners have reported major flakiness with their cars when the 12v battery connections are loose. This leads me to think there are situations where the DC-DC converter is too small to handle all the loads (without the battery to help), leading to a system voltage drop and all the fun that brings.

[@johndkelly45]

Bryan Noga what year is your Volt? I did notice they changed the DC-DC converter design in 2014. I do not know why. Maybe this is why

[@leokowalski]

Thank you for this interesting video! Greetings from germany.

[@WeberAuto]

Thank you!

[@pacowaco2765]

The Prius 12v battery does not crank the gas engine . . besides the electric power steering why does it need a full-size 12v battery ? I suspect a thumb size 12v battery can jump the vehicle using the jump points ? Your cigar lighter likely can jump it's own Prius ?

[@delta-vhybrids3808]

Thank you for this. Can you teach us insulation testing of stators? I have a fluke cat3 digital multimeter with insulation testing but I'm not sure about where to set it when testing mg1 and mg2. The multimeter settings for insulation tests are 50V ,100V, 250V, 500V and 1000V. Kind regards.....

[@WeberAuto]

Thank you! I am actually working on a video about mega-ohmmeters and milli-ohmmeters right now.

[@delta-vhybrids3808]

WeberAuto Great. Looking forward to it.

[@ivanbg5167]

Why is it a bad idea to jump start a regular vehicle with the 12 volt system?

[@bjron80]

Also prius/volt/leaf will be nice car to build big Audio systems on it. Because those have good supply on 12v power. So u dont need extra 12v batteries near amplifiers. Volt and Leaf also have 3-6kw AC charger so u dont need to buy big 100a 12v charger with poor effiency. And u got car charge also ;) Lot of Hifi events are indoors so no engine run allowed. Actually that forest festival can supply also from Leaf. There is chademo fast charger in 10km away. Leaf can be powersupply all weekend without extra trip to charger. Two day will take about 12kwh car battery still have about 20kwh.

[@WeberAuto]

Thanks for your feedback!

[@bjron80]

Thanks for great video. That 13A what electronic take is quite much if all devices were off. And of course there is also some usage in 200v side like BMS and contactors. Did u had AC button pressed when u turned blower to max? I think it was on because i heared ac compressor noise with frequency controller noise. Ac will draw about 2kw so cars engine started quite soon both times. Also when engine was on there was 8a more usage in 12v. Im thinking make 230v in small festivals. With 12v 600w inverter connected to 12v battery. Voltage dropped from 14.0v to 13.9 with 50a load. So 100a it will drop to 13.8v, still ok. I think its still better make that 600w with prius than small 4stroke aggregator. Noice and emission will be much smaller in Prius. Because catalysator and more effiency motor. Still extra power takers 13a+8a in prius might do that prius will burn more gasoline for that. Its like 8 hour event. On other way I wont do it with normal not Hybrid gasoline car. It need to be on idle all time and belt driven brushed alternator have so poor effiency, about 20% effiency.

[@WeberAuto]

Yes, AC on with blower on max, but AC compressor runs on high voltage, not the 12V system. With the engine running, there is also the fuel pump, fuel injectors, etc. Keep in mind that the DC-DC converter has a maximum limit of 100A on this 4th gen, 120A on the 3rd gen, 80A on the 2nd gen, and 100A on the 1st gen Prius.

[@bjron80]

Thanks for info. I was calculating engine start up times when 200v battery need to be filling up. With 2kw AC compressor and 14v 50a = 700w engine starts about 4x more often than just with 700w load.

[@bjron80]

Here are videotimes from engine; 14:51 on engine.. video cutted 76sec. 16:07 off engine video cutted 144sec. 18:33 on engine 71sec 19:44 off engine I would say that without AC on it will still load battery 60sec but use time will be 4x longer about 600sec. So it could have 1:10 engine on cycle. And it will have 10x more load to engine then just engine idling. So it do about 7000w when starting then use 700w for 10times longer and start again. Its sound good effiency load. But it still use just 0.116kwh of its 220v battery which is just about 1:10 of 1.3kwh battery. I thought it will use it always about half.

[@WeberAuto]

The AC compressor draws about 1.7kW on max cold

[@bjron80]

Here is link how to make chevy volt to power plant. kzbin.info/www/bejne/e3Sne56uZbiVrJY it is just for 12v side still but wont remove warranty or need authorizations. If u want really make it power plant it need to be taken from 400v battery and supply that power to 400v dc input 20kw 240v 60hz solar inverter. Thats how u will easily take 20kw out from Volt but u need to be professional for that. And warranty must ended so over 160000km driven models only.

[@funlovingJohn]

If you do not use your Toyota Avalon Hybrid let's say for 6 months, and your batteries do not have enough charge left to start the engine. By charging the 12 volt battery will it also charge the 200+ volt battery through the inverter converter?

[@WeberAuto]

No, but the HV battery should not run down in 6 months. The 12v one is supposed to be disconnected if it is going to sit for a while. See the owners manual for long term storage.

[@theblacktwinmusic]

I’m the 1000th like 😄 Love all the videos related to Prius. A very good teacher you are.

[@gmak1n785]

Great video thanks

[@WeberAuto]

Glad you enjoyed it

[@ricardofelippe834]

Very good explanation.

[@roberthuntley1090]

I've got a digital volt meter plugged into my car's cigarette lighter socket (on a 2019 Lexus UX), to keep a check on the 12 volts battery and recently noticed something odd when I put the car into Park. Background to my concern is that I had to have the car jump started during Covid lockdown, since I wasn't doing enough miles. Would welcome any comments/advice, thanks in advance. Basically, when the car has just started up I see 14.4 volts when the battery is charging, which drops to 12.4 volts once full charge has been reached - so far so sensible. It can take an hour's driving to reach this state. However, if I put the car into Park with a fully charged battery the voltage rises to 13.7 volts. My suspicion is that Park position slightly overcharges the battery with the strongest cells gassing slightly, and the weaker ones still absorbing charge and catching up (an equalising charge). Is this common to other Toyota/Lexus hybrids? Must admit, that I now routinely put the car into Park when stopped in traffic instead of leaving it it Drive (with Autohold enabled). Is it a good idea to leave the car sitting in Park for several minutes at the end of a journey. PS - The scary number is how low the voltage drops momentarily when starting the car. After being parked for a week, I often see it drop to 10.4 volts, and last week it dropped to 9.8 volts (only drove a few miles in the preceding fortnight). Any tips to reduce battery drain when the car is parked would be welcomed.

[@alanclarkeau]

John - thanks for this. I hear that the battery is a non-AGM battery - do you have any idea why TOYOTA didn't put in an AGM battery. Is a wet/flooded battery more suitable for what the PRIUS uses 12v for? thanks Alan.

[@WeberAuto]

The fourth generation Prius uses a regular lead-acid battery although is is a European Normal (EN) size. the owner's manual states that any lead-acid battery can be used as long as it fits in the battery tray and the hold down brackets. An AGM battery is not needed when mounted under the hood. Absorbent Glass Mat (AGM) batteries were used in the previous generations of the Prius because Federal Motor Vehicle Safety Standards (FMVSS) have special requirements for a battery mounted inside the passenger compartment or trunk. For example: 1.The battery must vent flammable gasses to the outside of the vehicle through a tube in the floor. 2. The battery must be properly covered to prevent electrolyte spillage on vehicle occupants in an accident. 3. The battery must be properly secured to prevent short electrical circuits in an accident or during harsh driving conditions AGM batteries are not required by law in these vehicles, but they are ideal for use inside the vehicle because AGM batteries: - Have non-spillable electrolyte - Are less likely to vent gasses AGM batteries have some unique charging system needs: 1. They must not exceed a certain temperature or they can vent gasses. This will permanently damage the battery. 2.Many have a charging current limit of 4-5 amps for no longer than 10 hours when using an external charger. There is no time limit when the vehicle's own charging system is charging it because it monitors the temperature and adjusts the charge rate to avoid overheating the battery. Anyone replacing an AGM battery with a non-AGM battery in an earlier Prius or any other vehicle is literally taking their life, and the lives of their passengers, in their own hands. I hope that helps. Best wishes.

[@simplyraw1369]

@@WeberAuto this reply was just what I wanted / needed to know! I have a 2012 3rd gen Prius somewhere I had read it's "just" a 12volt battery now I know that it is NOT AND the reason why too! I respect your knowledge and appreciate the sharing as well. I hope that those that can do make a donation too. I KNOW words don't pay bills. I personally would however my money is currently not even enough to pay mine That's why I am looking, reading & watching all about Prius! I actually googled how to test battery using a fluke on Prius. . My mechanic aka best dad ever! RIP ( though I know he isn't resting he is busy guiding me still!) I watched him many times so In my need I knew it was time to put it back to use. I don't believe in coincidences I believe there's a reason for everything and the reasons go beyond what we even know. Again My sincere thanks on many levels.

[@dougledbetter6607]

What is the maximum output amps the DC converter is capable of?

[@ReubenHorner]

He said about 100a at the start of the video

[@royamberg9177]

That's a complete check of charging System with out short cuts. One other check is voltage drop between converter and battery to see if cable is failing

[@WeberAuto]

Good point, thanks for the feedback!

[@shotatsiklauri6538]

Lot thanks. yesterday my car start problem. when starting in electric everything was ok, after gas engine start working on dashboard battery red light coms on and was not charging.

[@kasapis6]

Great information thanks , is the DC to DC converter a true Battery charger will it put the Battery in float mode like a true Battery charger .

[@WeberAuto]

Good question. I do not k now. This Prius had two modes of operation: 1. Charging control mode with variable voltage. 2. Voltage control mode with constant voltage.

[@kasapis6]

WeberAuto The reson for asking this question is if you run a AGM Battery in the back to run a small 12 volt fridge , using a 12 volt battery isolator , will the DC to DC converter charging the second (AGM Battery) will the Second battery get charge to 100 % ? Or is best to use a Battery Management System, with its own battery designed to charge and maintain the auxiliary batteries used thanks .

[@WeberAuto]

The 12V AGM battery in the back has a temperature sensor which is used to control DC-DC converter output. A parallel battery would have the same voltage applied, but the current can be different. It might work, but keep in mind that the normal current to the battery is supposed to be less than 10 amps in most driving conditions. Your refrigerator may draw enough to make the DC-DC converter to run hotter than normal. By the way, the 2004-2009 DC-DC converter is rated at 80 Amps. The 2010-2015 DC-DC converter is rated at 120 Amps. The 2016-2018 DC-DC converter is rated at 100 Amps

[@kornshadow097]

Isn't the -0.8 voltage from Battery output due to calibration issue? Or does the power actually leak voltage when it's off? Because wouldn't the output from inverter be the same amount of current going into the battery? (just as a negative on one and positive on the other,minus minimal losses?)

[@jasonmartinez7667]

How would you go about powering an aftermarket stereo system let's say 5000 watts?

[@ReubenHorner]

So if you disconnect that hall effect current sensor onto the battery it should go into constant voltage mode right?

[@drimranzaferbucha6790]

Please advice can I use a verta 45A battery in my 4th generation prius

[@WeberAuto]

I am not familiar with that battery. Thanks for watching

[@FrankODB86]

so the AGM battery is not necessary anymore in the recent hybrids?

[@raviautoscanning]

Great sir

[@WeberAuto]

Thanks for watching

[@jannke5965]

"The 2016-2018 DC-DC converter is rated at 100 Amps" - Is the 2021 Prius Prime rated the same? Thank you.

[@PandiKristo]

Hello i have 1 questions for you. What happened when negative cable hv battery connected with the body car .

[@WagnerCaixeta]

You are amazing. Tks for this video.

[@trublue2319]

You're amazing sir

[@sphericalsphere]

Looking at this, is there any reason whatsover that the 12V battery needs to be as large as it is? One could just get a 12V LiFe small CC Motorcycle starter battery. It weighs like a pound or 2 and can supply 300A and charge at 20A. It seems like it would have an easy life of just turning the computer on and maybe once in a while move a power seat while the hybrid system is off. Shaves an easy 30-40lb off the car for under $200. Might also save a little bit of electricity as it has higher charging efficiency and less internal resistance. And in my Lexus I would actually also gain some trunk space from it. Am I missing something here?

[@stevedutcher3875]

Off subject again, since my 2017 Chevy Volt service manual hasn’t arrived yet, how hard is it to replace the A/C compressor and where is located?

[@WeberAuto]

Very difficult, behind the engine. Why do you want to replace it? It cam be a very complex job flushing put the refrigerant system with the battery chiller in the system.

[@Mikesky10]

awesomes videos!!!!!!!!!!!!!!!!!!!!!!!!!!!1 when do you do a hyundai ioniq?

[@glenngoodale1709]

Two thumbs up from me!!

[@WeberAuto]

Thank you very much!

[@victorermita4972]

Hi, on the recent models of the Prius Prime can you tell me what the amperage is of the fuse between the dc converter to the 12v?

[@chubbysumo2230]

hey, I know this video is old, but hopefully you see this and can answer it, but is the DC to DC converter in the newer hybrids like the sienna and highlander hybrid the same nominal amperage rating of around 60 to 80 amps nominal?

[@rogerpinard2458]

During the test you 've a neg 4 amp reading and voltage decreasing according to me it,s the opposite you,ve 4 amps leaving battery toward accessories

[@funlovingJohn]

Is a 12V 50ah lithium battery safe to replace the OEM 12V lead acid battery in a 2019 Toyota Avalon Hybrid?

[@andpan3478]

Hello professor , why in order to charge the battery we need 4.2Amp and 10 hour , but the dc-dc charge the battery with 10 or more amps ?