Charging NiMH cells - smart vs dumb chargers

[@TechNinja.1701]

This video is especially handy because Clive has also briefly discussed different battery technologies from Ni-Cad, Ni-MH, Li-Ion, and Li-Fe-Po . I hope the search algorithm recognises this as well, so as to direct more viewers to this helpfully informative video - and the channel.

[@jkobain]

Yeah, it's hard to advise people what to use or not, especially when they forget to ask you about it. But Clive is very good at explaining crucial differences, advantages and disadvantages for certain use cases. I myself would like to see smartphones with lithium - iron phosphate cells too.

[@x--.]

Yeah, actually I could have listened to comparison on battery types for much longer. So fascinating and so, so difficult to find straightforward answers on what batteries you should get for what applications and - somewhat crucially for us thinking-types - why. Very cool, hadn't heard of the Li-FePo

[@highpath4776]

maybe we add links.

[@juanbrits3002]

Should've made the title to reflect it, should've helped.

[@vsvnrg3263]

@@x--. , i think older dewalt battery packs were lifepo. i dont think they are anymore.

[@rbleth51]

I saved 3 cells that I had tossed in the dead battery pile waiting to be disposed of thanks to this. Thank you Clive! Very good video! Can not count how many I have tossed over the years because of this.

[@ferrumignis]

@@manuelh.4147 That matches my experience, cells recovered from zero volts invariably have much higher self discharge after recovery and will be dead again within days.

[@Shaman_Ray]

Yeah, I find that once a cell's gone bad it has limited uses, clocks or TV remotes et al.

[@ecospider5]

My smart charger sometimes won’t charge a cell with 0.8v. So I put those in a dumb charger for 30 seconds and then back into the smart charger. I have hundreds of cells and this happens weekly but I only loose 1 cell completely about every 2 years.

[@MrJef06]

That problem has happened to me a few times and I suspected it was caused by not enough voltage in the cell for detection by the charger. What I do In this case is use pieces of aluminium foil to short the cell with its neighbor in the charger for a few seconds. That's usually enough.

[@swapshop864]

My kids night light bear flattens batteries in 3 days. One battery always drops too much and I need to boost it to be able to charge it. Have been doing that for 6 years and the battery still works. In applications like this, you can extend the useful life. But I agree, for other applications, I would not mix the degraded battery with good batteries.

[@arturtrzebinski2112]

For couple of years now, I recovered something like 50-60 Ni-MH cells from electronic waste bins placed near food markets, drug stores, postal offices etc. The 90% of the cells are totally good, have still high capacity and low IR. I use them on daily basis in my low-power devices, like clocks, humidity sensors or tv remotes. The majority of the cells are Eneloops, Varta, GP or Energizer, some of them are market's brands like Ikea, Auchan, Lidl. At first finding, I was like ""wtf? Why people throw out good cells to trash bin??". But now I think, people confuse them with primary batteries, or don't have proper charger, knowledge or abilities, to recover cells with 0V. It's a shame. So many good cells are wasted because of that.

[@no-damn-alias]

So you could build your own powerwall from them?

[@InterCity134]

What IR readings do guy get from them and how measured? I got some new eneloop AA that are reporting 120mO IR and am wondering if that is atypical. Measures IR with a smart charger.

[@arturtrzebinski2112]

@@InterCity134 I've got SkyRC MC3000 charger and it's plugged into old laptop. I gather data by dedicated app and it draws charts of temperature, voltage, current and cumulative capacity. I can analyze the charts and know when the behaviour of a cell is suspicious. Pretty nice feature. The charger allows to do an IR measure and for AA cells it reports something between 30-80 mOhm. Worn out cells can have something like 200-500 mOhms or even above 1 Ohm! Despite they still have some good capacity. What interesting, Ni-Mh cells seem to have higher IR when they are discharged. This is not present in Li-Ion cells. Also temperature rises when the voltage on a depletet cell goes below 1V. I also have Powerex MAHA C9000 charger. It doesn't display IR, but it tests cells with high current, and shows voltage during this test, which can be kinda indicator of low/high IR.

[@arturtrzebinski2112]

@@InterCity134 so, your 120mOhm can be okay. Try to fully charge the cell and then measure IR again. Also, the quality of contacts can influence the readings. My MC3000 sometimes is not connecting properly and for high drain SubC cells can show something between 8-50mOhms, despite these cells are claimed to have IR below 4mOhms.

[@OrangeUp]

Same experience here: ppl throw perfectly fine rechargeable batteries away. With NiCd an environmental disaster. Btw also from my experience more than half of the light bulbs disposed of at Ikea are fully functioning. I collect only LEDs from the Ikea bin by now. I wonder why ppl always complain that they have no money but throw everything away…

[@ScottsSynthStuff]

NiCd cells also have very low internal resistance, and can put out tremendous amounts of current. That's why aircraft (including helicopters) with turbine engines still utilize NiCd batteries to start the engines. They need a prodigious amount of current for less than a minute to crank the turbine up to light-off speed.

[@anullhandle]

Scott's Synth Stuff, they're used in f16 ejection seats as well.

[@magomat6756]

So for start a car the will also be good?

[@johndoe528]

@@magomat6756 They could, and they'd be lighter than a normal car battery, but do you want to spend three times as much on it and have it checked every 3 months?

[@ferrumignis]

I wonder if NiCd still has that advantage with modern high discharge lithium polymer cells? e.g. the car jump start packs can put out many hundreds of amps from a very compact size.

[@ulwur]

@@ferrumignisyou're right. The only advantage is the performance in low temps. At room temp lithium batteries are ferocious! Hobby lipo's easily outputs 100c currents without being damaged.

[@johnwelbourn3811]

I have that 7DS charger, and yes, I'm guilty of binning cells regularly that came up as "null". Another priceless video Clive, you've saved me a few quid there, so it's only fair that I should buy you a coffee.

[@tamask001]

Another handy trick with this particular breed of dumb smart chargers is that you put a good cell next to the flat cell in the charger and then bridge the positive contacts of the two batteries for a couple of seconds (with a piece of wire or a paper clip). This will kickstart the charging process.

[@jakublulek3261]

I have rebranded version of this charger and is really crap. Not only it has troubles to recognise cells, charges really slowly (current switching doesn't work) and NICD cells don't fit in it, also has troubles with cutting off charging when cells are charged. Multiple times I had it simply time-out after 12-14 hours when cells weren't charged according to the charger but were according to my other chargers.

[@Dutch3DMaster]

I'm honestly curious to check the pile at work the next time I'm in the office, we have a lot of supposedly dead ones. As for smart chargers: the only thing I'm usually happy for with them being in use for most of the equipment at work is that they tend to recognise alkaline batteries being pushed into them. Most of the time the charger recognizes them, has the display blinking and nothing happens, but on a few occasions they ruptured, so I would not want to know how much damaged equipment we would've seen with simpler trickle chargers. (And then there's the amount of people pushing batteries on the charger in reversed polarity, thankfully most of the ones we use at work are designed with a hardware type of protection: a ridge stops them from making contact on at least one side when reversed)

[@tarstarkusz]

I learned many years ago to only use the dumbest of dumb charges. I have an old (1970s) everready charger I use to charge my eneloops. It charges at 100ma and so a day on the charger is enough for the 1900mah rating of the eneloop batteries. I had a lot of batteries utterly destroyed by "smart" chargers. As soon as I started using the old low power chargers, I no longer had that problem.

[@vinnysworkshop]

What's a quid?

[@curtchase3730]

Years ago, I bought 3 GE NiCad C cells for a Sony transistor radio. Charged them with a stupid charger from the era many times over. Today, over 50 years later, I still have 1 of the 3 NiCad cells! It will still charge, hold a charge for quite sometime and produce current! Amazing.

[@Space_Debris]

I'm sure I would not be the only viewer who would thoroughly enjoy the disassembly and analysis of the smart charger you have present in this video.

[@fredmorton1631]

I thought I was the only one doing this trick. You just need to make sure when you are ' Kick starting ' them as I call it, to use a low voltage. I normally set my PSU at about 3V and give them 5 seconds. But Clive you didn't return to why the recovered cells show a full charge when they aren't. Good video and I'm sure this will save an awful lot of cells getting into landfill. TOP JOB !

[@revengenerd1]

I have batteries of different types, manufacturers, sizes that randomly stop working be they the only battery in a device or 2/3 together and just 1 stops working, when that happens I put them in smart charger and it shows a error code and I press the force charge button which gives them a small trickle charge and after a few seconds it detects the battery normally I can remove it from charger and put it back in device and it will last weeks or more, the battery wasn't drained it just had an error as if I left it in even at lowest trickle charge within a minute the batteries would always show at least half charge left often even 4/5.

[@nimoy007]

@@revengenerd1 Oh, what one has a force charge button?

[@whuzzzup]

I usually jump-start them by connecting them to another battery. But not in series, but + to + and - to - (with a cable then obviously). Do this for like three seconds and you're good to go.

[@ferrumignis]

Clive did mention the problem, dead cells that have just been "recovered" to start the charging process have high impedance, so as soon as the smart charger tries to push 1/2 amp or so through them the voltage jumps up to the 1.5v cut off level. Trickle charging them for a while lowers their impedance to the point that the "smart" charger can start working correctly.

[@vsvnrg3263]

@@nimoy007 , yes, i want to know too.

[@Chlorate299]

From my limited experience at Robot Wars - we built a LiFePO4 pack rather than a standard Li polymer pack because of the benefits to safer charging and whatnot, but we did find the cells overall were far less reliable - I ended up having to disassemble a battery pack in a hotel room and replace puffy cells in a hurry.

[@HootMaRoot]

Wasn't it in the rules to use life po 4 batteries because of the chance of LiPo cells having a chance of exploding/catching fire and putting out lots of dangerous chemicals in the smoke if/when a cell/s are pierced Tho I have tried to make older High capacity cells explode I have only seen small puffs of flames and smoke coming from a fully changed 5000mah 5cell battery no big explosions like you can get from over charging/discharging them at a much higher amperage than rated for

[@kitecattestecke2303]

@@HootMaRoot lipo sags go nicely boom if high charged and then pierced while under high load.. I only had a yellow 3S hobbyking lipo explode in mid air and it took the nose off the plane it was build in side :-9

[@Chlorate299]

@@HootMaRoot No, you could totally use LIPo cells, but they had to be charged separate from the robot and in special safety bags. We went with LiFe packs so we could leave the battery assembly in one piece. Turned out to be too much of a hassle and in the next iteration we switched to LiPos.

[@HootMaRoot]

@@Chlorate299 thanks, its been way over 20 years almost 25 since I read the rule book we got for robotwars. and mid to late 90s lithium cells where crazy expensive compared to 12v batteries in most motorbikes and don't think lithium they had quite the punch in them back then

[@Chlorate299]

@@HootMaRoot Yeah this was the 2016 reboot series, we had about 12 weeks to get an old robot that belonged to a friend of mine working again. Pulled out the old (and extremely dead) NiMH pack and built a LiFe pack to put in its place. Fun fact! Turns out NiMH cells have a much higher capacitance and thus do a better job of noise suppression than modern lithium batteries, this lead to some very entertaining issues with stray pixies getting into places where they shouldn't. We ended up fitting some big low ESR caps across the battery pack busbars to mitigate the problem.

[@LorcanAdrain]

I have one of those 7dayshop smart chargers. Always wondered why they did not recognised some cells. Thanks for this, it was very interesting.

[@gs425]

Wow 7day shop. Blast from the past !

[@jakublulek3261]

I have rebranded version and it is crap. Slow charging crap.

[@Agent24Electronics]

Your story about the charger meltdown is a good example of, why I don't like how every company these days seems to want to put cheap microcontrollers, and likely offshore, outsourced code, into every device within reach.

[@ATMAtim]

Man, I love your videos! You can explain in 15 minutes what would take a day or more to explain in a classroom situation. Thanks again, Clive.

[@DeCalDemz]

I've been waiting years for you to release this ideology on NiMh battery charging. Thank you Clive. My man 👍😎🤘🙌🙌

[@sepg5084]

Ideology?

[@zenaasura1769]

As a fledgling boat electrician. This!!!! Video has been soooo incredibly useful!!! Thank you so much for putting this out there. I will find a way to support your channel.

[@paulamos8970]

Very informative and not in the slightest bit rambling. When you have things to impart about products then limiting what you say is worse as you are not covering the subject to its full capacity 😊👍🏻

[@DaVince21]

It's thanks to you that I ditched alkaline batteries entirely for NiMH ones and I haven't regretted it yet.

[@affoh11]

My parents got us some of those IC3's back in the day. They were the first NiMH batteries I had ever seen. I was amazed how quickly they charged compared to other batteries. Unfortunately, I think we ended up losing all them over the years.

[@NiyaKouya]

Thanks for the video Clive! I discovered the trick with reviving "dead" cells that a smart charger would reject by putting them into a dumb one years ago, probably rescued a lot of cells from being dumped. My only contact with Li(Fe)Po packs so far was in context of RC vehicles. AFAIK they're pretty popular there because they are very robust, can deliver quite high amp values and have a decent capacity. But because they're more expensive than NiMH packs cheap RtR models often come with NiMH packs (really just several AA NiMH cells with shrinkwrap around them) that only last for 10-15min of usage and take ages to recharge...

[@kittenisageek]

I think the biggest advantage of LiFePO4 vs NiMH in RC vehicles is the recharge time. You can recharge a well-built high-current LiFePO4 pack in a matter of minutes, long before the one you're currently using in the car runs down. So with only two packs, you can go all day, swapping as the one in the RC dies.

[@spiffer27]

Great video Clive. Interesting and informative, I've saved it to my favourites. More rambly and disjointed videos please!!

[@tazz1669]

Thanks for that Clive, I always wondered why if I boosted a "dud" battery it charged normally again. I threw out some of those old dumb chargers guess I should have kept them

[@TechGorilla1987]

I have a "Miboxer" C4 charger and it measures and displays each cells internal resistance to determine charging current. I've been quite pleased with it.

[@markwarburton8563]

Not boring at all. I found it very informative and a reminder of things I'd forgotten too. Thanks.

[@k4be.]

The minus delta V algorithm stops prematurely (just after few minutes) with completely discharged cells, as the Ni-MH cell voltage dips a bit when it starts accepting charge. This is pretty common. And the common solution is to remove that cell from the charger, make sure it's cold (so not fully charged already) and put it back.

[@kyoudaiken]

Never had that happen with Eneloops and the BC700 charger.

[@k4be.]

@@kyoudaiken Probably because you treat the cells well. This typically happens when these are over-discharged, or even reverse charged, or left sitting somewhere in discharged state for weeks.

[@kyoudaiken]

@@k4be. This could be it. I don't have many devices with series cells. Just my bank's TAN generator and my kitchen scale.

[@ZeddZeeee]

very informative video! i have been using 18650s and such Lion batteries for almost 10 years and have had many that stopped working because 'magic', but this really put more into perspective and definetly more to think about! Thank u for the expert content

[@revengenerd1]

I have always wondered about jump starting batteries, I have had ones of different types and sizes that no matter if they are in a clock, or a tiny light suddenly seem to be dead or very weak I can put in a smart charger and I get a error code, and my charger has a button press that seems to send a jump charge into it for a few seconds and the battery comes back to life and often shows at very least half charged and I can instantly remove it from the charger and put back in device and it will act like new and last weeks or months more. I always wondered why batteries do that and if theres a better way to revive them.

[@millomweb]

I've a Uniross 4 AA cell charger that's a pretty quick charger and fails on some cells. I've also an Ever Ready charger from the 1980s Designed for AA to D cells (but will charge AAA cells if you make the length up :) ) and it suggests a 16 hour charge AND if you like leave cells permanently on charge then you have fully charged cells ready to go. I think this is the best way to charge them - you get them fully charge without overcharging, overheating or any other problems.

[@frankmoras63]

My smartcharger has a cycle function or something where you can test a battery and it slowly drains it and then charges it and you can cycle through the display stats and see the charge that it has given it. The batteries that weren't detected usually don't hold a proper charge anymore and have lost at least a third of their capacity. While the good ones from the same batch might have lost like a tenth.

[@FloTheBestEver]

I have made a bit of a discovery regarding false charge completion detection. At least on my Varta charger (Type 57674 - which is discontinued) you can reduce the likelyhood of an "early finish" by discharging the cell first. On the BC-x1000 (successor of your charger) it seems to work the same. Really great video, it's always nice to get confirmation in things you discovered over the years! Cheers

[@rpavlik1]

Very informative summary of battery tech! I will say, I'm not sure I'll ever buy an alkaline 9v/pp3 again except for smoke detectors, the ebl lithium ones are almost as cheap and last so much longer even without recharging...

[@MrAsBBB]

Happy Valentine’s. Spending it tonight with you and Andy. Cooked from scratch Satay prawns and chicken in sweet and sour. All the love xxx Now to the video

[@petraoleum5816]

Nothing wrong with a ramble! I have two things I'm curious about though: dumb chargers that charge batteries only in pairs, and NiMH AAA cells

[@Jeff44]

Daniel @ DiodeGoneWild has just made a video on one of those dumb chargers, he explains loads about them.

[@jkobain]

@@Jeff44 actually, Danyk showcased a *very* unusual charger this time, IMO.

[@jammin023]

I have a bunch of standalone PIR auto-on LED lights scattered around my house (to light the path to the bathroom in a less blinding way than switching on the main lights...) that take 3 AAA NiMH cells each (Ikea Ladda 750mAh). They each last a pretty long time but because I have so many of them I'm constantly charging... Because of the typical discharge curve that Clive mentioned, it's pretty obvious when a light's batteries need charging, as the light will suddenly appear much dimmer than normal, or it won't come on at all. Then I usually find that 1 or 2 of the cells are not detected by the smart charger and need a quick go in the dumb charger first to wake them up. I saw some comments that you should throw out a cell if that happens, but if I did that I'd literally be throwing them away faster than if I were using alkalines! What I do do, is if the smart charger reports that one of the cells has a much lower voltage than the other two that it was in series with in the light, I mark it with a Sharpie, and then if the same thing happens with a marked cell next time around then I bin it.

[@Jeff44]

@@jkobain There seems to be a slight misunderstanding of my use of the word 'dumb'. The word is used commonly to describe devices which lack advanced integrated circuit chips. Chips that would detect full charge and switch off charging etc. I'm actually a patreon supporter of Daniel and Clive, and have been for a very long time, so wouldn't speak disparagingly about either.

[@jkobain]

@@Jeff44 I guess we both could agree that we used the word in the same sense. I was speaking of that charger which bakes AA/AAA elements and has mechanical flap to switch from AAA to AA. I may have remembered it wrong, but it seems like that charger actually has some «intelligent circuitry» in it.

[@DiacriticalOne]

I wish I had seen this a few months ago… so many old batteries tossed because they would not charge. I’ve rescued a good dozen with a dumb charger and they’re ll back at work. Thanks for this!

[@danielegger6460]

You can also put a resistor across a NiMH cell in a smart charger to make the charger detect it (or bridge the neighbor battery over briefly with a paper clip). Some chargers also have a force mode. Some chargers are also super sensitive if you configure them into special programs to revive such batteries (either they just try to trickle charge independent of detection or they're supersensitive in such a mode, not sure).

[@zzoinks]

On BMWs they have a relatively cheap brake wear sensor that needs to be replaced once the brakes are replaced, as the system reports they are always worn, but I've heard that if somebody jumped the electrical connector with a paper clip, apparently they can be reused! Not sure what the science is or if that's even safe.

[@jasondemate]

Not rambly nor disjointed. Informative and covers a lot of ground on the subject.

[@simondavid2477]

I found the trick with dumb chargers revitalising "dead" cells years ago with car batteries. Same thing happens with overly smart 12V lead acid chargers. I would need to hook up my Halfords dumb charger for a couple of days before a smart charger would see it.

[@rpavlik1]

I've honestly used my bench power supply more in the last few years to revive car batteries than to do electronics...

[@25566]

This is how i revived a dead UPS battery, charged it directly from a computer psu (outdoors in case it exploded) and then the UPS recognized it

[@stefflus08]

Yeah, I do that all the time for snowblowers and the like, but for lead acid this really means end of life is near. There are ways to reform some of them but I need my car to start reliably even in -40°C so I can't risk it.

[@stevenconnor4221]

Car batteries I have an old antiquated simple charger that I got 30 years ago when it was old and antiquated. I just had to upgrade the bridge rectifier in it and paint it. It has the old 6v 12v bridge tap to change the output voltage. To be honest it's all I have ever needed.

[@rpavlik1]

@@stefflus08 stupidly enough, sometimes it just means it's a new car with a ton of electronics and a door and thus light was left on. That's all it took to bring a battery super low. I think at that time my bench supply might actually have been higher power than the charger I had, not sure if the charger refused it or not that time, but it was pretty dang low

[@imnotamechanic3491]

This is super helpful, we use a lot of NiMH cells and have a smart charger, but sometimes we put them in the camera and they don't last 5 photos - I know cameras are not best suited to rechargeables due to the voltage, but sometime they will last for ages. I will try a dumb charger from now on for those batteries.

[@bod9001a]

The pressure thing might have issues with going to high altitudes or when it's low or high pressure due to the weather, though it would be pretty amusing being told not to charge your batteries while it's stormy

[@ib9rt]

It's an amusing thought, but nothing that would actually happen in real life. Any change in atmospheric pressure is miniscule compared to the pressure changes inside a battery.

[@GGigabiteM]

@@ib9rt It's not as benign as you think. If you take a sealed bag of doritos from sea level to Colorado, it'll end up inflated like one of those metal party balloons, and in some cases rupture. Sure a storm isn't going to change atmospheric pressure much, but changing altitude sure will. Making a single product that functions in all altitude ranges is a big challenge. Depending on how sensitive the pressure mechanism was in the battery, operating the battery at an altitude different from where it was built could result in it not functioning properly.

[@nickryan3417]

Good point. I was also thinking that relying on a mechanical factor to protect a battery charging circuit would also be asking for trouble. Batteries get damaged, squashed, dropped and everything quite easily and if the mechanical switch was disrupted it could lead to quite an unpleasant charging situation.

[@iamjadedhobo]

@@GGigabiteM More fun is taking a sealed tub of ice cream up a mountain. The air in the ice cream expands enough to make the seal go pop :)

[@iamjadedhobo]

My worry with this technology would be arcing. Suddenly interrupting a high DC current isn't trivial. It is one of the reasons why switches have a lower DC current rating than AC current. So maybe enough of these cells showed (dangerous) issues that it was deemed sensible to stop selling them.

[@rogerhargreaves2272]

Thanks for sharing this. That explains why my Smart charger displays an error message when NiMh batteries are fully discharged. Placing them in my Dumb charger rectifies them, but takes longer to recharge. Also the Smart charger, although quick, never fully recharges a cell. Great info. Thank you.

[@Okabim]

What I like most about LiFePO4 batteries is that their voltage curve fits perfect within the voltage threshold of ESP32 & ESP8266 microcontrollers. Meaning you don't need to waste a bunch of power on LDOs for your IoT projects.

[@kittenisageek]

I agree. You can build a really simple CC/CV charge circuit using an LM337 and a MOSFET, then use USB power to recharge it without needing anything complicated like with other lithium cells.

[@Okabim]

@@kittenisageek i would love to see how you set that up!

[@kittenisageek]

@@Okabim I used a 10k pot to bias an LM337 for 3.65v --a bit above standard charge voltage for LiFePO4 to cover the voltage drop of a MOSFET. Then I biased said MOSFET in the current saturation region so that it would behave as a constant current limiter at 1a with a low resistance high watt resistor. I definitely recommend using through-hole packaging, as both the LM337 and MOSFET will dissipate a lot of heat. The circuit is not efficient; however, it is simple. During the bulk of the charge, the MOSFET will limit the current to 1 amp. As charge nears completion, the LM337 will limit the voltage and prevent overcharging the cell.

[@phillman5]

This has to be one of the best KZbin videos I have watched. Nice JOB!

[@gloomyblackfur399]

I've thought about using one lithium 14500 and one shorted "dummy" cell in place of two AA NiMH/alkalines, but the higher voltage remains a barrier (even with LiFePO4 cells). It'd be quite the paradigm shift to redesign all those AA/AAA/C/D devices. ≈1.5v per cell has been standard since the days of Zinc-Carbon.

[@tbelding]

Which begs the question - Why did the lithium battery developers end up at 3.7 volts nominal? It seems like it would have been more reasonable to have gone for a multiple of 1.5. 1.5, 3.0, 4.5, 6.0. That would have allowed a "four D Cell" unit to be able to run off of one, two, or four "lithium" cells.

[@kjur18]

@@tbelding It's the chemistry that dictates what voltage you end with. There can be differences even with lithium ones, primary lithium cells have around 3V, some li-ion variants can get up to 4.35V. Very small watch batteries can be around 1,55V It's all about what makes a battery.

[@tbelding]

​@@kjur18 - That's both true and not true. _Physics_ dictates the end voltage. Chemistry dictates how the energy is stored and released. Alkaline batteries can be built in many different voltages. They just have established a standard of 1.5 volts, with a _new_ charge voltage of 1.6 to 1.65 volts. (Clive used 1.5 because it's close enough and simple to use). Just as a rechargeable Li-Ion tends to have a charged voltage of 4.1 to 4.2, and a nominal of 3.7 or 3.8. As an example, Edison's first alkaline battery was .75 volts. There have been other voltages as well - I'm guessing that 1.5 was chosen because the numbers scale roundly, and they've stuck with it ever since. Otherwise, there's no reason that the 'heavy duty' batteries would have the _same voltage_ as the 'alkaline' batteries. They're totally different chemistries. They _can_ make 1.5 volt lithium batteries. Energizer sells them. They have no circuitry in them to drop from 3 to 1.6 volts. So, there has to be an arbitrary reason why they settled on what they did. Heck, it could be that the first person that really worked out how to make non-exploding ones just liked one size, and that was the voltage that came out. So everyone else copied it.

[@fluffyblue4006]

I'm using LiFePO4 14500's and dummies for years now. The charger charges them until 3.65V and then stops. The cell's voltage drops back to 3.25 to 3.3V fairly quickly after the charge ended, without any load. From that point, they are safe to any device. Keep in mind that devices should be designed to not be harmed by two new alkalines that might have 1.6V, totaling 3.2V. If in doubt, fabricate a dummy with a schottky diode in it. It'll take 0.3V off.

[@kjur18]

@@fluffyblue4006 some time ago I got some 14500 lifepo4 that supposed to be used with some solar garden lights. I used them to replace 4 D size cells in electric stapler. Even though they have around 600mAh, I only charged them once, and used it for more than 1000 staples. There was no need for any dummies, just some wires and one douuble AA battery holder glued to battery compartment door.

[@surgingcircuits6955]

I had unknowingly reinvented the cell recovery method with a power supply that you showed. So, thanks for the confirmation! Good vid!

[@Chris_Grossman]

An excellent summary! It would be good to talk about using NiMh in place NiCd since many replacement batteries for devices designed for NiCd are NiMh.

[@bigclivedotcom]

Most applications are a direct swap, but not ultra high current ones or where there is heavy continuous trickle charging.

[@RexxSchneider]

At 8:10 - No, Clive, the Li-ion cell is *not* fully charged when the voltage reaches 4.2V, and the charger does not stop. In fact, there is a significant amount more capacity available. A smart charger will switch from constant current to constant voltage charging, holding the cell voltage at 4.2V while the current steadily decreases. It only stops charging when that current has dropped to 10% of the normal constant current used.

[@soulmate07748]

Wow! I still have one of the Rayovac chargers and the AA and AAA batteries that came with it. I always wondered why they stopped making those. Too bad they discontinued.

[@Agent24Electronics]

A perfect cell that can't be overcharged doesn't have a place in the planned-obsolescence mentality.

[@GreenJimll]

Yep, me too. I got one back when digital cameras took AA batteries (ah, when I were a lad... ;-) ) as they seemed to have a much better capacity and life than "normal" NiCd and NiMH cells.

[@PhoneVidoes]

Yep got a Rayovac charger and two AA's here too, still works fine as well.

[@DFX2KX]

The Renewal batteries did have issues. I remember them not really having many cycles in them, and being VERY expensive to replace. But as clive mentioned in one of the other comments, they had issues with bursting too. Regular Nickel cells are durable enough, though.

[@wolfierarar9652]

It's never too rambly... nice one BC ❤

[@senorcapitandiogenes2068]

I always have an old dumb-charger lying around my smart-charger. I have A LOT of different NiMh/NiCd cells, some are old and dont have a noticeable delta-V anymore or some are down to 0 volts and the modern """smart""" chargers refuse to charge those. Slap 'em in the 80's chargers and they work like a charm.

[@jhonbus]

Great video! I have an Energizer charger that charges any NiMH cells in 15 minutes, but it doesn't have any of that fancy pressure detection. I don't know how or even if it detects when the cells are charged, but they get absolutely screaming hot and that's even with a cooling fan built in. It has a separate wall adaptor which puts out 65 watts. Into four cells. I actually use that wall adaptor to power my TS100 soldering iron.

[@bigclivedotcom]

I think that style of charger uses thermal sensing. It can cause cells to vent and reduce their capacity.

[@McTroyd]

I bought an Opus BT-C3400 off eBay a while ago, and for the most part, it's been great. However, I witnessed a similar crash while top-balancing some NiCd cells out of an old drill battery -- one slot just appeared to go totally berserk with the current. The charger had been plugged in for a long while at this point (matter of weeks or months). I figured it's a buffer overrun in their firmware somewhere. My solution was to only have the charger plugged in while using it. Been fine for years now. Simplest solution is usually the right one, right? 😁👍️ Edit: Pro tip for the BT-C3400 (and maybe other models) -- there's a tiny switch inside my model which selects lithium charge voltages. It comes set at 4.2 volts, but offers 4.35, and 3.7. I use the latter mode to store 18650s at ~50% state of charge. A dremel helps access the switch without a screwdriver. 😁

[@vventurelli74]

I can't believe all of the products at our disposal that we have straight up missed through the years just due to timing and exposure. Rayovac's I-C3 battery technology looks amazing and I was able to secure a bunch of factory sealed cells and chargers, I am excited to make a transition into the past that possibly proves better than the current and future options. I have some lithium AA batteries that recharge directly with a MicroUSB cable, and while they do hold capacity well, they have a very steep drop-off and they still take a decent amount of time to charge, north of an hour usually, which is fast, but not 15 minute fast. True 15 minute charging sounds amazing and would be handy for work where a bunch of battery powered lighting is used and the batteries can be charged in-between jobs as needed. (They have a car charger for them that I picked up as well)

[@altronixvideo]

As a kid way back in the day, I remember my grandfather topping up the charge of his AA's by putting them in the fireplace to heat them up (not in the actual fire obviously)

[@vsvnrg3263]

altron ix, i well remember learning about this trick as a kid. we were at a christmas picnic and santa claus had left his megaphone turned on so when it was time to call out our names to get our pressies (pre-arranged with consultation with our parents) he couldnt. the batteries were flat. so us kids had to divert our attentions while the batteries spent 1/2 an hour in the pie warmer. then everything was alright.

[@MikeSmith-sh3ko]

The fact is there is always one cell in a battery that will go down first and if you jump change it this way it will do the same thing next charge and discharge cycle. Although you can get it going like this it probably is still a bit unreliable compared to the others . I always mark the cell that I have jump charged so I know that cell maybe suspect in future. Good work Clive 👍

[@GadgetBoy]

Bonus comment! :P I had one of those, and it had this really loud fan that blew through the batteries and charger circuitry. Now I know why the fan would vary in speed as the battery filled.

[@not_just_burnt]

oh god i learned quite a thing here today, thank you so much. i threw out so many NiMHs in my life and i shouldve done that trick with trickle-charging those, but now i know!

[@bills6093]

I had a couple sets of Rayovac Renewal rechargeable alkaline cells and a charger. They seemed to work really well. Whatever happened to those cells?

[@bigclivedotcom]

Rechargeable alkaline cells were problematic. They only lasted a few tens of recharge cycles and were prone to leaking.

[@DFX2KX]

@@bigclivedotcom That would explain why the user manual of my TI calculators said your warranty was void if you used them. Shame, as playing games (what we all REALLY used our 83s for, lol) ate through batteries pretty quickly.

[@BrianG61UK]

@@bigclivedotcom I had a set of 4 rechargeable alkaline cells and a charger. They never really even charged once. I think maybe they had been on the shelf too long before I got them.

[@colinpye1430]

Very interesting. I’ve had great success with the non-Rayovac Pure Energy rechargeable alkaline batteries. For years I used a set of four AAAs, keeping two of them in the charger, and the other two in my Palm III, swapping them every week, even if they still had lots of life left. The big thing, the more you charge them, the better they lasted. They didn’t like getting fully discharged, so you should treat them the opposite of NiCd, charging frequently. Pure Energy is(/was) located in Amherst, Nova Scotia, so I was doing a bit of flag waving, recommending them to every Palm user I knew.

[@paulk8io445]

As a young ham radio guy with little funds at the time, I was using old surplus Nicad cells for my radios. I learned about cell reversal and the recovery technique. Some cells were really bad but a good (quick) knock from a 12 v high amp power supply would bring many of them back to life. Nicads will also gain a memory and short cycle on capacity if put on charge before fully discharging regularly. A smart charger that discharges the nicad to 1 v and then start charging ensures the best life from a nicad. I find smart chargers not to smart sometimes as well.

[@PrototypeNumber5]

I have the same style charger. It's actually really easy to get it to start charging a completely dead cell. Just use a paperclip and bridge the positive of the dead cell with another already in the charger that's properly charging. Keep bridging for several seconds until the display flashes and shows it's actually charging (vs just checking the cell). I generally don't have an issue with a dead cell only taking a small charge unless the charger resets itself in the middle of the charge (mine has a fiddly power connector).

[@muxerbaker4638]

Small push button switch for each holder that bridges them would work as a "force charge" button for these then.

[@johngarritzcx6733]

COUGH, COUGH, du(mmy)Cell😁😁😂😂

[@azureprophet]

I totally just tried the trick with a good battery applying charge to one that the charger marked as bad and it worked after just 10 seconds of holding it on there. Thanks!

[@valije]

I bought a bunch of eneloops in 2009 (at the time they were made by Sanyo, later bought by Panasonic). They still work today and they hold around 80% of capacity (tested with a Maha C9000). I think only 1 in 20 went bad. A bit more expensive than other NiMH cells but better by a long way. It is a shame each time you see a review of "the best NiMH cells" the long term reliability is missing.

[@grayrabbit2211]

Fwiw, I have a few old, vintage Eneloops which my C9000 refused to charge. Tossed them into an XTAR VC2S and it was more than happy to charge them despite being a "smart" charger.

[@mrcrunch8000]

Even when they were thought to be sanyo they were still Fujitsu. They are the oem of the Japan made Eneloops and their Fujitsu nimh batteries are the exact same. It blows my mind that even after all these years Fujitsu is rarely mentioned.

[@Canal_em_Vazio]

@@mrcrunch8000 Something that most people don't know is that the vast majority of the good quality Ni-Mh batteries (Sony, Panasonic, Sanyo, Philips, even Duracell and Rayovac I'd guess) are made by one same manufacturer: the FDK Corporation, either in their factories in Japan (Takasaki) or in their factories in China (Xiamen); Even the Fujitsu branded batteries are actually made by FDK (Fujitsu itself is just a brand, it labels itself on Ni-Mh and Alkaline Batteries, HVAC systems and Servers, and the Fujitsu brand is owned by the Furukawa Group). The exceptions to this rule are the Ni-Mh batteries developed by chinese companies (mainly GP and generic chinese batteries), which of them I don't know exactly which is the manufacturer (probably GP itself but I have a lot of questions about this inside my head).

[@mrcrunch8000]

@@Canal_em_Vazio well, the Japan Duracells are rebranded eneloops, Sony idk but Sanyo was the ones before Panasonic, all those are made by the factory owned by FDK or Fujitsu. I'd be at a loss for words if that wasn't common knowledge by now considering how long all of that has been known. About the other stuff you mentioned Idk. I know that is a group of companies but they have no hands on with anything Fujitsu does. Everything I have seen shows it very similar to something like a bank or group of investors owning companies. They aren't actually making anything. I only find mention of Fujitsu being a member of the group but actually a product of Fujitsu Electric and a German company I can't remember the name of.

[@fatblokes_ferguson]

brilliant explanation of battery technology. I used to buy broken mobile phones that would no longer take a charge or even start to charge, I built a small battery booster just to give the battery a tiny bit of power so the onboard charger would then start. I used to get funny looks when I explained that I jump start mobile phones. this would be a great video to explain this. I must add, I did not over charge or use a higher voltage. it was just enough to get it going on its own.

[@nrdesign1991]

When putting cells in my "smart" charger that can also take larger than AA cells, I can briefly short a "bad" cell to a "good" cell, to give it the tiny bit of boost it needs. The -ΔV method looks for a negative dip in voltage caused by a rise in temperature. Once the cell hits its maximum voltage and then creeps back a few mV, it is fully charged, and heating up.

[@WilburJaywright]

11:10 this makes sense to me now. The same was true of a trailer we once had. As long as the battery didn’t go too far dead, we could use the onboard smart charger that would automatically stop when the battery was full. If it got too low, however, we had to connect a dumb charger that could not tell if the battery was charged or not, but would charge it from absolute zero volt. Thx for the explanation! 😊

[@mithrillis]

Speaking of charge levels, I remember those odd alkaline batteries with a power indicator strip on the outside. You press very hard on two white dots and the indicator shows the power level of the battery. I wonder if the same trick could work for rechargeable batteries as well. That'd be really handy.

[@whitslack]

The flatter voltage discharge curve of nickel-based cells would make those simple meters less linear, I expect. You could still have a Boolean good/not-good indication, though.

[@rpavlik1]

Yep, that was just a resistor and heat sensitive ink. You were just shorting it out gently 😉

[@25566]

@@rpavlik1 it was so cool to see as a kid, and that thing got pretty hot;

[@casemodder89]

these things helped the manufakturer sell more batteries as everyone pushed the test zones and discharged the battery at high current in doing so. pretty clever marketing, energizer !?

[@ferrumignis]

It was a good way to waste some cell capacity, those indicators drew quite a lot if current.

[@lindafoxwood9091]

Thanks for this video. I always wondered why charges worked so differently with my batteries.

[@ToumalRakesh]

Hey clive! Check out "Reflex charging" sometime, it's an actual charge method (instead of a cutoff method like du/dt) that pushes in bursts of current, followed by a short discharge period. The goal is to minimize memory effect. Obviously not really a thing anymore with lithium cells.

[@awebuser5914]

"Reflex" is only applicable to NiCd cells, not NiMh. It was all the rage waaay back when in the R/C racing community was looking for every possible way to get more voltage out of a NiCd pack! In my experience, the cells that were reflex charged did have a significantly lower temperature at the end-of-charge.

[@ToumalRakesh]

@@awebuser5914 Back when I was playing Airsoft, people were switching from NiCd to NiMH and I bought a reflex charger specifically for my then-new NiMH packs. The reason why I'm so sure about it is that it had a NiMH setting ;) Now, whether that charge method is actually good for the cells, or works better for NiCd I really don't know. The method wasn't really new even back then though.

[@awebuser5914]

@@ToumalRakesh Well, the whole reflex charging thing was mostly marketing with no real proven performance gain, but in any case, this is from the Competition Electronics site, who is (was) a very high-end manufacturer of R/C chargers (Turbo 35 GFX costing $400+): "Your T35-GFX includes a feature called “TurboFlex”, also known as “burping”. TurboFlex is only intended for use with NiCd cells."

[@craignehring]

To this day, I use Ray-O-Vac cells for applications that require a alkaline cell. They were also a way to help sustain a local company. I love all types of batteries but I hate leakers and we all know what brands do that. In recent memory I can not recall a Ray-O-Vac leaking under any circumstances. Great tutorial Clive, I learned something and I did have some of them crazy Ray-O-Vac's

[@Kandralla]

I had an unopened box of Rayovac's that had leakers in it that had never been used. They were only 2 years out from manufacturing. The irony is that it seems like the no name alkalines now do better.

[@dhgmllcshea5038]

No more Rayovac cells for me...I had new Rayovac C cells leak in< 1 year, eating a hole in the aluminum tube ofmy $60 fancy emergency tactical flashlight. I always liked Rayovac's for their replacement guarantee policy if cells leaked. I had never used that guarantee but it suggested high standards. I Contacted them, sent photos of the hole eaten clean thru the threads of the body tube and they suggested I clean it out with vinegar. I a. never buying Rayovac again.

[@nrbudgen]

I noticed an odd problem which was revealed by my smart charger. One of its features is that it can measure the cell's internal resistance. When a new set is first put on charge (say 4 at a time) the internal resistances of all four are closely matched. However, after being used a few times the resistances start to change and are no longer matched at all. Why is this?

[@chrisengland5523]

Another excellent video from Clive. His videos are always very informative.

[@FortuneRayzor]

Well there goes my fear of permanently destroying a new batch of Eneloops in a tiny slow USB charger that I forgot to unplug and realized it the next day. Yay. But since then I'm using this "smart" per-cell fast charger that was sold with Eneloops and that thing is very consistent and certainly recognizes half discharged batteries. Never had any problems with it, maybe it's because it not that smart. Put batteries in, plug it in the socket, unplug after green lights go out. Simple.

[@Knaeckebrotsaege]

I have one of those white self-contained Eneloop/Sanyo chargers that came with a set of them. It's a dumb charger, just a decent quality one

[@FortuneRayzor]

@@Knaeckebrotsaege I have the KJ55MCC40E "Smart & Quick Charger" from Panasonic. There has been quite a few models over the years. Dunno what qualifies as a smart charger but it's certainly more advanced one. Only with no buttons or display.

[@Knaeckebrotsaege]

@@FortuneRayzor Hm... seems like your BQ-CC55 is a revised and "slightly smart" version of the dumb one I have from over a decade ago, which is a Sanyo (this is before they sold the battery arm to Panasonic) NC-MQN04. Seems like the modern version of my oldie is the BQ-CC51. Surprised how similar they all look though in this day and age of "let's redesign everything for no reason other than being able to say "we've done something"" lol

[@andchip.s]

I have a UNROSS 15 min charger slimier to the Ray-O-Vac you talk about, I will have to dig it out now and investigate. Thanks again Clive for your great insights.

[@BrianG61UK]

I've never had a smart charger reject a cell because the voltage was too low. Normally they reject them because the internal resistance is high. There's no reason a charger would fail to see a low voltage cell - it sees the voltage drop when you put the cell in, the voltage dropping even further makes it more detectable not less.

[@Kandralla]

It depends on the "smart" charger. I think the good ones detect a battery by pulsing the contacts and waiting to see a current, cheap ones look only for a voltage.

[@BrianG61UK]

@@Kandralla They can't be that cheap if they're somehow sensing that there's no battery and are switching off the charging voltage. I don't understand why they'd go to all that trouble only to make the product worse.

[@phorton7039]

You are always full of useful information and explain the details in an excellent way BUT your title description refers ' Charging NiMH cells - smart vs dumb charges'. I got to half way through the video and all it was albeit very good explanation and details about various rechargeable batteries. Nothing about the comparison between the two chargers. That is what sparked my interest to view this video.

[@Ryan_Thompson]

Sometimes you have to watch the whole video, I guess. Clive did discuss both chargers. The black 4-cell charger (smart) and the silver 2-cell charger (dumb) were shown at various points, with discussion on the relative merits of each.

[@phorton7039]

@@Ryan_Thompson Thankyou for your reply. I figured he would eventually cover the subject but at the midway point I lost interest. I am sure it was an oversite. The author needs to be aware what the title implies and in this case only about the chargers. I'm sorry if I appear to be nitpicking but I have seen so many videos that employ this as a click bait tactic. Getting you to watch their video and sometimes don't even cover the title or what is shown the thumbnail. I know Clive means well and just needs to be more aware on selecting his titles.

[@Ryan_Thompson]

@@phorton7039 I hear you. I can get unreasonably angry at clickbait. I guess Clive and his audience are used to his more laid back, sometimes slightly erratic presentation, and you can always trust him to present something interesting based on first hand knowledge and discovery. If you want a boiled down, straight to the point, breaths-edited-out style of video, though, I respect that, but that ain't Clive. :-)

[@senorcapitandiogenes2068]

I have had an Eneloop AAA that went to 2 Volts after being charged in a dumb-charger at 200mah for 4 hours. I have no idea how that could have happend.

[@sdnative2387]

4:12 I immediately thought the same thing when the phone manufacturers started designing the phones with a non-removable battery.

[@gregorythomas333]

I have some Radio Shack NiMH cells that were manufactured in 2001...they are still going... though at a reduced capacity...so I use them for my coffee stirrer. Nite Core is my normal charger but every now & then it doesn't see them...I put them in a dumb lithium charger for about 3-4 seconds...it shocks them up and the NC can see them. The Rayovac IC3 was so good that the other battery companies told them to stop making them because it was making the other companies took really bad

[@straightpipediesel]

If US DOE/California CEC battery charger efficiency requirements (the circle BC mark) didn't kill them, they are likely preventing them from coming back. Those regulations impose a wallplug kWh to battery kWh efficiency limit, and those IC3's dissipated a lot of power in heat.

[@mazdaman1286]

I have several cells that my smart charger has rejected ...the job for today is jump starting......thanks for the info 👍👍👍👍👍

[@Nono-hk3is]

We haven't seen the Explosion Containment Pie Tin in quite a while. Just saying.

[@bigclivedotcom]

It's currently full of shady lithium cells.

[@marksntl7632]

Clive, Thanks for sharing you video. Another great one with good explanations. I have a Maha C9000 Pro Intelligent Charger + Analyser.... On this I can set the charge current to suit the capacity. It stops the charge with negative delta V and then trickle charges at 0.1C (C/10) and has over temperature sensing to stop too. The instructions explain very well about charging Ni-Mh and Ni-Cd and how to set the charge current. On refresh and analyze modes you select the capacity too....

[@CamelCasee]

Some smart chargers measure ESR too and will reject cells based on that alone.

[@digitalchaos1980]

Awesome video and super informative!! Even for an old tech such as myself. But one small correction, even if it seems trivial. Electricity flows from negative to positive, not the other way around. Keep up the great content and be safe out there, Clive! 😎

[@simonneep8413]

What about recharging non-rechargable alkaline batteries? My dad used to trickle charge them to some benefit... Clearly cheaper than buying rechargables in the 80s!

[@jamhough22]

You cant charge an alkaline battery, they wont accept much of a charge if any, and probably overheat.

[@bigclivedotcom]

There are techniques for partial recharging, but they often pressurise and vent.

[@samuelfellows6923]

🤨… I have heard about a charger called ”battery wizard”/that I have seen in catalogs, that claims it can recharge nominal battery’s with pulse charging - how does that work?

[@rpavlik1]

@@samuelfellows6923 not well 😉 I think he might have an old video on that

[@revengenerd1]

My dad did that, and I do sometimes. I notice the tech works but the issue is they discharge really quickly when not in use so if you used them straight away you would get the benefit of it but within a week or so the battery would be dead again.

[@paranoiia8]

One time I had similar story as you, but with 18650 battery, I was charging it in new charger that I got, left to do something, came back and battery was one step to be glowing thermonuclear bomb, it was so hot that plastic case of charger started to be WAY to flexible and smelly. I immediately got it out to metal container and left outside for whole day. But later I did small test and it turn out it was working good even if it was "boiling" it self to death for few hours. It still kept around 1100mah(from 1500). Its amazing that it managed to survive it...

[@peter.stimpel]

"rambly" and "disjointed" are not the adjectives I would use for this video. "Informative", I guess

[@Boogie_the_cat]

My problem in the past is using cheap (even though name brand Duracell or Energizer) "pair" charging units. These were readily available at my local CVS. However, they would regularly either kill NiMH batteries, or else refuse to charge them due to charging them in pairs, and the voltage of the pairs not matching (I'm guessing) Ever since I got my "smart" charger that charges each cell singly (although it will accept 8 at a time) I have not had this issue. Also, after reading specs, I noticed that Energizer and Duracell NiMH batteries have mAh capacities that are shameful when you consider the price. I know when buying off-brand batteries online not to always believe the written specs, but due to the much greater weight of these cells (and their long lasting capabilities) it seems obvious that the mAh capacities printed on them are close enough for DMV work. Thanks for spreading the good gospel, my man, and BTW I learned of your channel when I saw your humorous comment on Barry Lewis's famous grilled cheese toaster fire video.

[@bigclivedotcom]

The quality of the stuff from the prominent brands is surprisingly low for the money they charge. They deserve the title zombie-brands.

[@revengenerd1]

Years ago my dad recharged watch batteries on his slow charger by putting a normal rechargable battery in and putting the watch battery above the normal battery, seemed to work!

[@bigclivedotcom]

Not recommended, but they do take a slight charge.

[@muzikman2008]

Excellent explanation big C 😎👌thanks! I bough a smart charger for my many nickel metal hydride batteries, from lidl years ago. I bought eneloops too and they're great! Much better than the cheapo ones I used to buy.

[@SimonCoates]

Who remembers the 'memory effect' charging NiMH.

[@bigclivedotcom]

That's associated with NiCd and is controversial.

[@SimonCoates]

@@bigclivedotcom It happened with NiMH batteries but wasn't as obvious as with NiCd. Remember those mobile phone chargers that also discharged the battery then fully charged it. The good old days when you could have a couple of spare high capacity batteries on charge even though the phone lasted for a week 😀

[@igrim4777]

@@bigclivedotcom It's not controversial. People simply experienced voltage depression or other loss of capacity and called it memory effect without any evidence. Memory effect was only ever seen in high precision applications with high capacity cells. The man on the street with his AA or his D cells never experienced it. His unregulated discharge levels in his tools or his kids' toys and his unregulated charge regime, throwing it in his untimed dumb charger and hoping to be awake and at home 16 hours later, never even came within a country mile of being able to produce memory effect.

[@SW-ci9zv]

Discovered these excellent videos from bigclive. Kept me amused during "lock down!". He is entertaining with his little chats. Obviously there will be some that are not quite so into his stuff, but THANKS and FULL CREDIT to the presentation / variety / clarity of the videos.

[@Viniter]

I knew a dominatrix who did incel charge control...

[@BEYTEK]

Id like a Lipo battery in my bar but i take it we cant charge it with straight DC? or would it need some sort of circuit on the battery? Lots of old drone batteries left over

[@97marqedman]

This video topic is quite timely, as I’m working on rebuilding the old 7.2v NiCad packs from my old Snap-On screwdriver. Was curious about switching to NiMH, but the charger is the issue I’m having. Thanks!!!

[@EpsilonsReviews]

My old metal detector used NiCd batteries and I’m thankful because to charge them, I had used a similar rated power supply and just straight up applied the stripped wires to the batteries. It worked like magic and I still have the danger to this day

[@TheSpotify95]

Good video and review. I have plenty of rechargeable batteries, in both Lithium and Ni-MH. I also have smart chargers and dumb chargers, and I too have found out that the smart chargers have failed to charge batteries on occasion (whereas the dumb chargers have charged them without issue). This is especially the case if the voltage has dropped a bit (especially below 0.7V). This also likely explains why I have salvaged various Ni-MH and Ni-Cd batteries out of battery recycle bins, that have not only took a decent charge, but have also had close to full capacity as well. One time, I managed to get over 100 Ni-MH batteries (GP 2100 series and GP 2600 series mostly) for free, and the vast majority still held a good charge.

[@PhillipBicknell]

I'm still using an Ansmann Energy 8 and getting what seems to be good results even from cheaper and now quite old NiMH cells. I see Ansmann now do chargers with digital displays, but the basic LED system on mine does the job. Occasionally I have to stop, remove, start again to overcome what is presumably a mis-sense. I was happy enough with my first unit, that when it failed, I just bought another - and Ansmann are still selling it after all these years.

[@MrDschubba]

Great explanations thanks Was glad to confirm my suspicions of a high internal resistance causing charge to cut off early. Took 4 goes until they kept charging. Big fan of the joule thief in the day thanks btw

[@tomhoehler3284]

I read where Toyota is using NiMH cells in their soon to be released pickup truck. Toyota has learned a great deal about NiMH from their experience using them in the Prius. Very reliable battery packs, some are still usable even after 10+ years.

[@cbs1710]

BEST Ni-MH CELLS TO BUY, VERY USEFUL INFO: To my knowledge, all IKEA NiMH rechargeable cells ("batteries") are actually re-branded Eneloops. In multiple tests across the interwebz and KZbin, they - together with Eneloops - are consistently by far the best performing NiMH cells you can get. + They should probably be cheaper than the equivalent pack of Eneloops. Still, just to be safe, check that the packaging says they're made in Japan. To my knowledge, there is no other kind (i.e. sourcing country).

[@Kitteh.B]

I, too, have had a handful of what I thought were perfectly good Eneloop cells that I've just had sitting in a drawer because I thought they mysteriously died. Gonna give the bridging method a go and see if that can save them! Thanks Clive!

[@tonyweavers4292]

Another excellent explanation. Thanks Clive.

[@etcetera1129]

This video should be a mandatory part of primary education

[@mattfleming86]

"They want you to buy a new phone every year" Me: Laughs in Galaxy 7 taped to a battery pack.

[@ChrisBigBad]

when charging a few batteries from a LED light that sucked one cell basically dead, at least one of them shows usually up as NULL. I stick two thin pointy kitchen knifes into the positive terminals and jump-start the NULL slot with the charging slot. works a treat!