Can't believe this actually worked. Haha, found two old rechargeable batteries and thought hope was lost for them. Tried this and the charger is reading them now. Very cool!

To balance nimh battery packs, a circuit with two 1n4007 diodes in series plus a resistance of 1 to 10 ohms is used.The voltage drop in each diode is 0.7 volt x 2 is 1.4 volts.The resistance limits the intensity of the balancing current. Being soldered to all Ni cells this increases the life and performance of the battery pack.

This was so easy, Thank you so much. I had a few rechargeables i thought were toast and your simple and easy method did the trick.

You can use any higher voltage good batteries to "Revigorate" any dead 1.2V NiMh batteries this way, but the "revigorated" battery may or may not hold charges. I've tested this method on a bunch dead 1.2V NiMH batteries。 I managed to bring all of them back to at least 1.2V, but the smart chargers still could not charge any of them. I tried on a couple of "dumb" chargers and connected the charger with a volt/amp multimeter to the power source. The meter showed the charger was sucking correct volt/amp currents. After the meter showed there had been ~300 mAH charged, the battery being charged was already 1.4V+, but actually there was no power at all in the battery--tried the battery on a few things such as electric razors etc. and it was just as dead as it was before being "revigorated."

@BenInSeattle

3 ай бұрын

"There's a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there's usually only one thing you can do..."

Thank you for this video, it helped me save a nearly dead battery.

So you simply connect both batteries in parallel...with a short but hard discharge of the good battery in the bad one , to try to equilibrate the common voltage. Not good for your Eneloop. Don't repeat the operation often. If the bad battery is new but simply completely discharged (mistake) you can do this. If the bad battery is old with high internal resistance, with this method the recharge will be possible, but with only a few milliamps. This battery is good for the trash. You can do the same with lithium batteries when the voltage is too low in one of them, to save a GOOD battery which is only discharged. And please don't wait and let the battery too long discharged. The best is to avoid this!

My phone at my office had some very old NiMh in it. Only being on the charger and until Ingot that office maybe used once a week for 2-5 mins calls and then back on the charger. Horribly lazy batteries. What brought them back was some cycling and sometimes I wrapped them in aluminium foil for a short circuit and let them like that for an hour and then back in the charger. What ultimately did the trick is to discharge them completely then put them in the freezer and afterwards gave them a jump start with my lithium jump starter for a few seconds. They certainly weren't happy but now they work fine again

Thanks! I knew this could be done, but I forgot the procedure.

I built a rig with a 100W incandescent lamp, a diode, a battery socket, a switch and a wall plug cord. Works well for nimh and lead chemistries, and gives a visible indicator of sucess/failure.

Interesting stuff!

Way too hard. I use a single wire. I hold it one end against the negative (flat) end of the dead battery, and hold the other end of the wire against the negative end of a good battery...then I just tap the positive ends of the two batteries against each other. Takes seconds and works every time.

I got so tired of jump starting my batteries, I got a good, safe but dumb charger that just apply low current without too many "probing" of the battery. It revived nearly all my batteries. I have gradually reduced the use of "smart" high-speed chargers for NiMH and NiCd chemistry batteries. For safety reasons, they build so much "smarts" into those chargers that they are very prone to error.

It worked

Is there a quality battery charger out there that can also do battery revival like you did, using the second battery?

@TheCuriousEngineerChannel

2 жыл бұрын

Great question. I feel I'll make a video on this, so stay tuned! Thanks for watching!

@ThunderStruck94660

3 ай бұрын

I just use a one amp trickle charger. I touch the battery for a half sec and they work.

I apologize if this is a silly question, but can I ask why you don't put a resistor in there to reduce the current? In another video you say that "dead" NiMH batteries can often be slow charged (with a bench power supply that limits the current). I have heard that LiIon and LiPoly can fail due to crystal formation and that a high current "jump start" can break up the crystals, resurrecting the batteries. What benefit is there to shorting the batteries together for NiMH?

I'm trying to revive some ni-mh camcorder batteries made for '90s camcorders. Is there a way to adapt this for smaller, surface terminals? If this works for the first set I can still buy more of (they're just annoyingly expensive) i want to try it out on the other similar batteries of which i can't find new production versions that i've accumulated in buying so many old camcorders.

@TheCuriousEngineerChannel

Жыл бұрын

Those Ni-MH camcorder batteries are likely not low self-discharge, so they might have formed a "memory effect". Typically Ni-MH experience this less intensely than Ni-Cd, but it can still occur. One way to try to resurrect them, is to try to "form" the cell again, buy slow charging it for a lengthy period of time. Perhaps I'll make a video on this. Contact directly if you'd like to discuss in more detail. Might make an interesting project! Thanks for watching!

* THANKS * ********

I have two Energizer NiMh and one is fine, but the other shows it charged then test it and I get

Maybe a stupid question, could I use a Lithium car jump starter to do that trick, with its crocodile clamps ? It's going to be 12V though, even 15 if I have to use the override mode... Could that be dangerous for any (myself, the jump starter, the old dead battery) ?

@TheCuriousEngineerChannel

Ай бұрын

That's a pretty high voltage to apply to the cell, along with a very high surge current coming from the jump starter. I wouldn't recommend it.

Hi there, can i use Li-ion 3.7v to jump start a NiMH 1.2v ?

@TheCuriousEngineerChannel

2 жыл бұрын

I don't recommend it, as it might exceed the maximum current output of the Li-Ion cell, and cause...issues. Thanks for watching!

I pulse 30 volt reverse (Negative to positive) to the battery for about 10 times. Battery gets very warm but show proper polarity of 1.35 volt after. Still trying to understand why...

@peterv1602

Жыл бұрын

Why using reverse polarity? He "jump starts" by connecting positive to positive, and negative to negative.

@sobrangbigat

Жыл бұрын

@@peterv1602 I had always done it his way - positive to positive - on Ni-Cad & Ni-MH, even lithium that has completely drained to zero volt and would not charge. But I did reverse polarity out of curiosity. That was 5 months ago... battery still works fine at this moment. I still don't understand why it work...

@peterv1602

Жыл бұрын

@@sobrangbigat Interesting. Maybe some battery expert can jump in.

@christopherleubner6633

6 ай бұрын

The hydrogen is absorbed into the powdered nickel making the cell act like a hydrogen cell

I got one IKEA Ladda Ni-MH battery that reads 1.3V but I cant charge it, charger keeps blinking. What can I do?

@christopherleubner6633

6 ай бұрын

Put a very high voltage through it, I use a 120v cord through a 100W lightbulb rectified by a diode. It will start dim then light up brightly. Once it does this switch off the light and pop the battery in the charger.❤

How does this work? It looks like the charged battery is forcing electrons to go the wrong way. Electrons flow from negative to positive iirc. Are you "pushing" electrons into the dead battery's negative side?

@621ELECTRONICS

2 жыл бұрын

He is paralleling the good battery to the bad battery, much like you would jump start a dead car battery, simple as that. Positive to positive, negative to negative. I think you're picturing batteries in "series", but he is trying to jump start a bad battery, not combine two batteries for higher voltage. If he did them in series then connected the jumper wire, he would have then fed a reverse voltage into the bad battery = very bad. He did it correctly by paralleling them.

@TheCuriousEngineerChannel

2 жыл бұрын

Well said!

@camilosixtino

Жыл бұрын

@@TheCuriousEngineerChannel Do that work with any alkaline 1.5vbattery?

@DigitalMoonlight

Жыл бұрын

@@camilosixtino No, don’t recharge alkalines, even with proper alkaline chargers. They lose capacity very quickly and it greatly increases the risk of leaks. Alkalines designed to be recharged mitigate this but are more expensive than decent NiMH such as the Ikea Ladda series.

@christopherleubner6633

6 ай бұрын

When deep discharged the hydride will passivate similar to the plates in an electrolytic capacitor. This will cause the battery to charge up like a poorly built supercap. By using a higher voltage through it you can disrupt the insulation layer and make the battery take a charge. This also works for old lead acid batteries so long as the plates are physically intact.

2 screwdrivers side by side lay the batts between. Make parellel connections with driver shaft problem solved. Doesn't make for a very good vid though.

Is there any way without having this additional kit?

@TheCuriousEngineerChannel

2 жыл бұрын

Not safety, no. Some chargers have modes that will try to do this for you, and attempt to "reform" the battery. I'm looking into getting one of those chargers. Thanks for watching!

@LordGryllwotth

2 жыл бұрын

I used a car battery charger and I had it on very short. Or was it for a few seconds? But anyways it showed 1.2v right away! I wonder why it works. I read something about hydrogen?

1•Youre using a USB cable? Why not simply use a regular piece of wire instead.Serious question...not trolling.👍 2•Also...no battery will last forever,regardless of any trick of salvation.So,WHEN do you become aware its time to let it give up the ghost? 3•And lastly,I hear of a battery,Rayovac NiMH Hybrid Rechargables (if you can find them) are the latest in battery high quality. Supposedly,they keep a charge MUCH longer than regular NiMH rechargables.Are you aware of such batteries? Thanks for any light you can shed on my 3 questions.🙂

@TheCuriousEngineerChannel

2 жыл бұрын

1. I didn't expect everyone to have higher gauge pieces of wire laying around. Most decent USB 2.0 cables have good ground shielding that can easily handle high current. Wire works fine too. 2. Agreed. I thought I explained in the video that these were accidentally over discharged to 0Vdc. 3. It's on my list! I have five other tests ongoing with different battery brands, so stay tuned! Thanks for questions and for watching!

Or just use a dumb charger to kickstart it

@littleman787

2 жыл бұрын

But the dumb charger won't charge either right, if the battery is entirely run down to 0V, and the dumb charger has a min detection of 0.5V to start charging?

@littleman787

2 жыл бұрын

This somehow just worked for me, thanks!

Dude Your clamp reads AC current not DC. Use a shunt and you can protect your meter while making DC current measurements.

@TheCuriousEngineerChannel

3 жыл бұрын

Hah. The UNI-T UT210E clamp meter measures both AC and DC current up to 100A. But yes, you can also setup a shunt resistor and measure voltage drop across it.

@elkiddo1114

3 жыл бұрын

@@TheCuriousEngineerChannel Dude, Wow, I stand corrected then. I've had several clamp meters and none of them ever measured steady DC current. So what brand of meter is this? Thanks Dude.

@TheCuriousEngineerChannel

3 жыл бұрын

You are welcome. The company is called UNI-T. Look for a review, and as you probably guessed, a teardown in an upcoming video!

@LordGryllwotth

2 жыл бұрын

@@elkiddo1114 I have a fluke clamp who can measure in DC, when you zero it, it doesn't react to the earths magnetic field when you rotate it. But the cheap one like his does.

@elkiddo1114

2 жыл бұрын

@@LordGryllwotth Lord dude, I want one of those, what's the brand and model. Thanks dude, I'm besides myself.