Minimal mAh capacity before you throw away cells ?

E

educa

New member
Joined
Aug 2, 2020
Messages
1
Hi there,

This is my first post on this forum. I currently have around 200 pieces 18650 cells and am currently busy testing them all with Liitokala Lii500 tester.

I have cells from laptop battery packs and also cells from e-bikes

When I do capacity checks, I find cells with 2000+mAh but also cells with for example only 600mAh

What do you guys do with these lower capacity cells? From what mAh capacity level do you consider them usable ? Or are some cells project and lower capacity cells in other projects? Wondering.....
 
Minimum 75%-80% of original capacity for powerwall, Ebike, mobile powerwall, minimum 2000mAh
minimum 60% of original capacity, non critical loads, usb powerbanks, other projects

Later floyd
 
I ditch all below 2Ah in general. No use having them here when i have so many above it.
 
Whether or not low capacity cells are of any use depends highly on your context, e.g. if you have many low drain devices such as clocks, scales, keyboards, doorbells, meters (e.g. for volt/amp/temp) then even low capacity cells may still be of use, since they may have much better capacity than smaller (e.g. button) cells they replace, and they also may have lower self-discharge (e.g. vs. standard NiMh). I'm assuming that some of those devices you may have convertedto use Li-ion.

Btw, I have replaced all of my 9V batteries with (EBL) 600mAh Li-ion 9V batteries, e.g. in all of my multimeters. They've been working fine for over 4 years now. I'll probably never need to buy a 9V alkaline again. Good riddance!
 
Low capacity cells could be used in things like torches, toys, solar yard lights, etc. Things where it's not critical if they just flat out stop functioning.
 
80% of new is a good qualifier. Judging cells by capacity really depends on how easy it is for you to get cells and whether it's worth it to you to use more of the lower capacity cells or hold out for better ones.
 
I don't use anything below 2000mah don't even look at how degraded the cells are - probally should but thats SO much extra time researching each cell
 
2000mAh? Wauw .... :s

I definitely need to look for a better source of batteries. :(
Mine are all below 2000, only 10% make it.
 
hbpowerwall said:
I don't use anything below 2000mah don't even look at how degraded the cells are - probally should but thats SO much extra time researching each cell
Click to expand...

exact same thing here.
I just have a few other applications for 18650 cells besides the powerwall like solar lamps and portable speaker system - and therefor I am using good ones.

All cells below 2.000mAh go to eBay to refinance the project (correct: they've gone. eBay.de forbids selling single 18650 cells since this week, just allows whole akkupacks which are non-defective)

All below 500mAh is going to the recycling company.
 
hbpowerwall said:
I don't use anything below 2000mah don't even look at how degraded the cells are - probally should but thats SO much extra time researching each cell
Click to expand...


Good point in term of efficiency... I will use below 1800 to replace a UPS Battery :)
 
I'm hoping to use Samsung 30Qs exclusively in my Powerwall. I have a good source for these atm. Excepting duds of course (which only accounts for around 5~10%), most of them are testing at, at least 95% SOC. I think this is because they are still fairly recent to market, so I'm getting packs that fail early in their life leaving good cells. Like any cells, the longer they are on the market, the more you get that have failed later and therefore have reduced SOC.

I will stil use 20Q and 25R for other projects such as UPS and camping packs, and of course 18650ing devices that never had them. I just converted a Bluepoint screwdriver. It had 3 x 2/3 subC NiMh that were dead. A single 21700 fit with room to spare. In the charging base, I used a 12v PSU board and a TP5100, connecting to the original charge pins. Works a treat!
 
My source cells were all 1900 or 2000 when brand new, I know many people wouldn't touch those, but I have a source for a LOT of them, and all for free. I don't have a source for other capacities, let alone free. So I'm using these ones. I realize that means any pack I build will have to be physically larger for the same capacity, but it's a tradeoff I'm willing to make given my source of cells.
 
The question is how much they degraded basically. Tht factor is more important than the actuall capacity.

Ie

SOH > Capacity difference between cells in a pack > Factual capacity per cell.
 
You must log in or register to reply here.
Back
Top