Deep discharge revival and capacity retention performance between brands: What's your experience?

tatasal · 2018-08-02T07:10:33.000Z

When I started this hobby in 2012, lithium-ion batteries were quite rare then (specifically 18650s) and we have to settle with the usual ‘Fire’ batteries/light/charger combos.

I then bought the highly-regarded Pila IBC and the Maha C9000 to start it right.

When I became a member of both forum (CPF, then here), I became aware of the horrors, deceit and dangers of the ‘Fire’ batteries so I turned to discarded laptop batt packs just to get hold of Panasonic, LG, Samsung, Sony and Sanyo brands, after which I bought the iCharger 105B+ hobbycharger just to be able to analyze these cells.

Most laptop packs I got were perhaps discarded due to a hard use (except in some cases), most of them stayed at less than a volt for years.

Fast forward to today, and we arrive to the crux of this thread: In my experiences with cell revival or recovery from ultra-low stored voltage, I noticed that the Sanyos were the worst performer, meaning, most of them cannot be revived at all.

Even my brand-new ones lose their capacities faster than all the rest.

I have experimented with all those brands mentioned above, and noticed the LG brand as the most robust in revival percentage, with LG and Samsung as having high capacity retention among the and types currently available.

For the record I have opened almost fifty packs of different makes.

Even my brand new Sanyo 14500s that were accidentally over-discharged, three out of five were not able to make it back.

XXX-Man · 2018-08-02T12:34:35.000Z

I have exactly the same experience as you.

I have opened exactly 128 laptop battery packs with usable cells and some more with dead cells which I didn’t count (I keep spreadsheet with all data about usable cells: battery model, cell voltage when opened, tested capacity, etc…) and Sanyo cells are usually the worst. Even if they have good capacity they like to heat up when charging and I recycle them as I believe cells heating to temp high enough you can+t hold them at 0.5C charge is dangerous.

Quick look at my spreadsheet says capacity is usually in this order:
1 LG
2 Samsung
3 Sony
4 Panasonic
5 Sanyo

This is only relative to battery packs I got and may be very different for someone else.

tatasal · 2018-08-02T22:12:04.000Z

XXX-Man:

I have exactly the same experience as you.

I have opened exactly 128 laptop battery packs with usable cells and some more with dead cells which I didn’t count (I keep spreadsheet with all data about usable cells: battery model, cell voltage when opened, tested capacity, etc…) and Sanyo cells are usually the worst. Even if they have good capacity they like to heat up when charging and I recycle them as I believe cells heating to temp high enough you can+t hold them at 0.5C charge is dangerous.

Quick look at my spreadsheet says capacity is usually in this order:
1 LG
2 Samsung
3 Sony
4 Panasonic
5 Sanyo

This is only relative to battery packs I got and may be very different for someone else.

Yeah, I vividly remember a set of Sanyos from a pack that was from a friend’s laptop that was dropped and ruined the internals. Got excited to receive the pack knowing the pack was still relatively ‘okay’ compared to packs with unknown history. Opened it and got all about 4.0v each cell, as compared to my other batteries that were usually 1.8v to .72v, and thereabouts.

Loaded it up on my charger and it was a good thing I never leave the charger when testing batteries from old laptop packs. The Sanyos, all of them, heated fast and really hot to touch.

XXX-Man · 2018-08-02T22:17:00.000Z

Over 50% Sanyos I got overheat when charging, even if they test almost full capacity.

I don’t understand why this happens but since first one I don’t leave them alone when charging even if they were cold last time.

tatasal · 2018-08-02T22:27:24.000Z

@XXX-Man: Were your laptop Sanyos also in their usual OEM Red wrappers?

XXX-Man · 2018-08-03T00:03:38.000Z

Yes, they were.

Red and engraved (don’t know exact word) markings.