Bringing A Lithium Battery Pack Back From The Dead

[Wilhelm]

On the topic of batteries... if you are trying to make a new battery pack...you really need a spot welder. It IS possible to diy one using a heavy 12v relay, big capacitors and a power supply.

It really is the best way to tack weld the tabs onto the cells.

Carry on gents

Just get cells with tabs already on them.

I am very cautious with batteries in general.
Any signs of deformation, leakage, oxidation, noticeably reduced capacity and I toss them ASAP.

Those praised "Fast Charge" chargers are battery killers, and people wonder why their batteries won't last more than a year or two.

One needs to have spare batteries at hand and let the depleted ones charge slowly.

I recently got a Nitecore Digicharger D2 smart/inteligent charger off eBay for charging individual cylindrical batteries up to 65cm in length (18650 for example).
It will automatically check and recognize the battery type and charge level and charge each cell accordingly.
It can charge different cell types at the same time, and one removes and inserts a cell while the charger is under power.
The charger has an output of only 500mAh per charging bay (D2 has two bays, the D4 has four) making it a slow charger for high capacity cells, then again the output is not too high to charge small batteries too.
The Nitecore D2 charger keeps info on the charge cycle of each bay which I find helpful and informative.
If an old depleted 900mAh 1.2Volt NiMh AAA battery is deemed charged after lets say 30 minutes it pretty much tells me that the cell is on its dead bed and dying.
If a brand new 18650 LiIon cell claiming "5800mAh" (as if!!! I mean who falls for that crap?! ) is deemed charged after merely an hour or two it clearly does not feature the advertised capacity. And no, I did not intentionally purchase the "580mAh" cells, they came with a gadget! I have two 2100mAh Sony VTC4-C4 18650 cells now and two more being shipped, they take over 4 hours to fully charge in the Nitecore D2 charger which gives a good indication of their true capacity.
So far I really like this Nitecore D2 charger very much.
I am fairly new to individual cylindrical LiIon batteries and I wanted a reliable charger, the D2 (2 bays) seems to be hitting the sweet spot, though in retrospect a D4 (4 bays) would have been nice too.

 

[3browns]

I have the D2 as well

So far it’s a pretty impressive piece of kit

The days of the single red light that turns green chargers is long gone

It’s incredible how much thought goes into this gear

I have a lot of cells scavenged from my last Windows laptop batteries and they were thoroughly tested and charged correctly and I use them in non critical stuffs and they work fine

YMMV

And as others have said and demonstrated, be careful

The same folks who shouldn’t run saws probably shouldn’t mod Li-Ion batteries

 

[Lightning Performance]

I just keep tapping them with double the voltage for thirty seconds on used stuff I buy. If that don't do it they are usually toasted.

 

[Mattyo]

Sometimes you can buy batteries with tabs but sometimes you can and often the tabs are going in the wrong direction. So for instance if you are remaking a battery pack for your power equipment...it's nice to have a spot welder.

 

[Wilhelm]

Sometimes you can buy batteries with tabs but sometimes you can and often the tabs are going in the wrong direction. So for instance if you are remaking a battery pack for your power equipment...it's nice to have a spot welder.

No arguing on that!