Minimal mAh capacity before you throw away cells ?


SLS BATTERY AUCTIONS are now live at www.batteryhookup.com EV, Lithium, LifePo4, Inverters & More

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.....
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,500
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
 

daromer

Moderator
Joined
Oct 8, 2016
Messages
5,662
I ditch all below 2Ah in general. No use having them here when i have so many above it.
 

gauss163

Member
Joined
Jun 28, 2020
Messages
278
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!
 

Korishan

Moderator
Joined
Jan 7, 2017
Messages
7,005
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.
 

TinkerGear

New member
Joined
Aug 4, 2020
Messages
5
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.
 

hbpowerwall

Administrator
Joined
Oct 7, 2016
Messages
2,100
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
 

Bigfoot48

New member
Joined
Feb 12, 2019
Messages
12
2000mAh? Wauw .... :s

I definitely need to look for a better source of batteries. :(
Mine are all below 2000, only 10% make it.
 

Stefanseiner

Member
Joined
Apr 16, 2020
Messages
136
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

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.
 

507PowerWall

Member
Joined
Jun 6, 2020
Messages
103
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


Good point in term of efficiency... I will use below 1800 to replace a UPS Battery :)
 

Wayne's World

Member
Joined
Jan 28, 2020
Messages
86
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!
 

green1

New member
Joined
Sep 11, 2020
Messages
22
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.
 

daromer

Moderator
Joined
Oct 8, 2016
Messages
5,662
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.
 
Top