Ever heard of the freezer trick for old Li-ion batteries?

GregP507

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I've tried it twice so far with amazing results. You simply put the battery in a freezer bag and leave it in the freezer overnight. I don't know if this is a critical step, but the next day you don't wait for the battery to warm up, you just put it directly on the charger.
The first one was a Dyson hand vac with a battery that was about 8 years old and had provided shorter and shorter runtimes until it was finally unusable. I ordered a new battery online, but in the meantime I froze the old one. When I had it charged, I tried a runtime test to see how long it would run. It ran over 6 minutes straight, which is comparable to what it did new. The manual claimed 9 minutes run time, but I'm not sure it ever went that long when new.
The other is a laptop battery that has faded since I bought it new around 2012. It was only charging to 91% indicated, and when unplugged, I got about 5 minutes out of it before it died. I tried the freezer trick, and now it indicates 100% charge. I'll update on the runtime test.
Update: I got 1h 31m playing a movie.
Not bad I'd say for a decade old battery.
 
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idleprocess

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Everything I've read about common li- chemistries - Li-ion, Li-poly, LiFePO4 - states in no uncertain terms that charging must only be done above freezing temperatures. 5°C is a commonly-recommended minimum.
 

arrgh my eyes!!

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IMO charging a frozen battery is a bad idea. If you want to try this I would suggest waiting for it to return to room temperature first.
 

aznsx

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Everything I've read about common li- chemistries - Li-ion, Li-poly, LiFePO4 - states in no uncertain terms that charging must only be done above freezing temperatures. 5°C is a commonly-recommended minimum.
Agreed. 'Trial and error' can get one a long way with some things in this world......but lithium ion cells and batts is definitely NOT one of them:)
 

GregP507

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Everything I've read about common li- chemistries - Li-ion, Li-poly, LiFePO4 - states in no uncertain terms that charging must only be done above freezing temperatures. 5°C is a commonly-recommended minimum.
Appreciate the advice, but if it's stupid and it works...
 

idleprocess

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but if it's stupid and it works...
If it's stupid and it works, it's still stupid and you're lucky.

I don't know your charging setup, hazard mitigations you may have undertaken, nor your risk tolerance - but you're markedly increasing the odds of an all but impossible-to-extinguish fire that produces gobs of acrid smoke. The NFPA has some light reading on the subject if you're so inclined.
 

jtr1962

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This is something I might try just for kicks with LiFePO4 but no way would I do it with regular Li-ion. I also have a feeling that if anything helps it's being in low temperatures for a while, not recharging at low temperatures.
 

Monocrom

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When you charge a battery, there's going to be some heat transfer involved. And, some chargers can get amazingly hot. Just sounds potentially dangerous to immediately charge up ice-cold batts.
 

aznsx

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Opinions may (and do) vary, but I was under the impression that this was not a matter of opinion, but was firmly in the realm of "settled science". Is it not?

*****
Batteries operate over a wide temperature range, but this does not give permission to also charge them at these conditions. The charging process is more delicate than discharging and special care must be taken. Extreme cold and high heat reduce charge acceptance and the battery should be brought to a moderate temperature before charging.

*****
 

PhotonWrangler

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This seems like an extradorinarily bad idea. Most of the videos that I've seen of lithium battery fires/explosions have occurred while they were charging. I won't leave a lithium battery charging unattended for this reason. Charging them while frozen produces a greater thermal shock and could cause the battery's internals to expand unevenly in ways that could cause internal damage.
 

chip100t

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I don’t know why but this thread put me in mind of a documentary I watched where the film makers followed around the doctors at a Jamaican ER.

There was a gentleman brought in with severe burns because his toilet had become blocked and he decided to fill the bowl with petrol and light it hopeing to clear the blockage. But instead exploded his toilet, showering himself in flaming faeces.

It’s probably because they both seemed like a good idea at the time but could result in you laying in a hospital bed thinking “I probably should not have done that”.
 

PhotonWrangler

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When I was a kid I learned that I could partially revive zinc-carbon C or D cells by drilling a couple of small, shallow holes near the base aid sitting them in a cup of water to rehydrate the electrolyte. They were called Dry Cells but the name was a misnomer; they were technically damp cells.

This would definitely end badly with more modern battery chemistries though. 💥🔥
 

jtr1962

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I don’t know why but this thread put me in mind of a documentary I watched where the film makers followed around the doctors at a Jamaican ER.

There was a gentleman brought in with severe burns because his toilet had become blocked and he decided to fill the bowl with petrol and light it hopeing to clear the blockage. But instead exploded his toilet, showering himself in flaming faeces.

It’s probably because they both seemed like a good idea at the time but could result in you laying in a hospital bed thinking “I probably should not have done that”.
Your post made me think of this review I read on Amazon.

 
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