Let's go !

Hello everybody,
First please apologize for my poor English, I'm French.....
I just start to built my Powerwall.
I already colect around 850 cells, from laptop.
Some from bad laptop battery, some from old laptop.
about 140 battery pack collected for freein 3 days.
I will run a MPP MPI hybrid inverter, 5,5kw, DC battery 48V.
I will first built a "One block 48V 18650 battery " 14S15P, just for process building.
Yesterday I have recieved my first OPUS charger, today the result isn't so good.
Many cells have very low capacity. lower than 1ah.
My setup will be from solar panel (6 x 300w) and Pelton hydrogenerator around 800Wh 24/24 -8/12month)
I plan to built a14S80P and if it's working well, I will add another 14S80P.
This forum is very helpful for me.
thanks .

Welcome!

Generic numbers is that you get 40% of your cells that will be above 2Ah. So out of your 850 cells you will perhaps get somewhere around 340 cells at most.

This of course depends. In some batches i have had as low as 20% and in some above 80%

cristof said:

...
Some from bad laptop battery, some from old laptop.
about 140 battery pack collected for freein 3 days.
I will run a MPP MPI hybrid inverter, 5,5kw, DC battery 48V.
I will first built a "One block 48V 18650 battery " 14S15P, just for process building.
Yesterday I have recieved my first OPUS charger, today the result isn't so good.
Many cells have very low capacity. lower than 1ah.
...

Click to expand...

Hi!
Begin by just checking the cell voltages.
If it has about 2.5v or higher, it can go on the Opus.
If it has 0v and open circuit on continuity test, send it to the recyclers!
In between, if the cell can be recovered, it should get a VERY gentle charge - which is not one of the Opus skills. But it is what the very inexpensive TP4056 module does. If it comes up to normal voltage without heating, then you can test it on the Opus.
Voltage check to find some good cells first, and test them on the Opus. That should make you feel better before tackling the others!

I'm working on a 7S setup. My first string has cells over or near 2000mah (max is about 2400, but not a lot of those). 100p

I think my average is about 1800mah, and I'm happy to use 1800mah as I build more packs.

If I get enough cells in the 1400-1600mah range I might add a 140p string with those and see how it goes. A bit more space, but still over 200ah capacity in a 7s string. I'm curious about the longevity of such a string. I need more cells in that range before I try it though.

Any Pics of your 48V pack?