Magic Extreme X8 LifePO4 upgrade

[shirley_hkg]

https://www.wheelchairdriver.com/board/ ... 77#p206077

New-in-Box PowerLab_8 v2

[emilevirus]

Well, the cell I ordered from US was undercharged compared to the others :/ I've been charging everyday for the past month ~8h a day and it's still out of balance. I should've charged them all individually before putting it together. I didn't think the difference was gonna be that huge. Getting better tho. Now it's at 3.34v while others sit at 3.6v.

[shirley_hkg]

That's cooking the high cells.

Charge the low one individually, with ZXD (alligator clips), or PL8.

[emilevirus]

I'd have to take the whole chair apart again. Ugh..

[shirley_hkg]

Just access the two terminals.

Via the balance leads is also feasible.

[Burgerman]

OR...

Set on PL8.

Discharge for a few hours at max power.

Charge at 3.45V per cell and set balance to start at 3.40 volts. Then it wont hurt the battery sitting at top voltage for many hours.

Once they all appear charged, THEN reset the charge voltage to 3.550 per cell or 3.600V. Set balance to start at 3.50V. And let it /charge/balance

[emilevirus]

Finallyy! I woke up this morning and it was fully balanced.

[Burgerman]

Next time...
Best not to hold any lithium cell at 3.600V for long periods. You do that while it balances normally a few mins each charge, plus 15 to 30 mins.
Thats a nessassary evil in order to balance and charge. This voltage is above the cells normal full voltage.
When charged you should stop.
Then the battery can relax a little and drops to a lower 3.4x volts after a bit where it is more happy. At 3.6V its like a man that breathed in a full lungful and is holding his breath about to burst!

Even this is a little evil though and if you are not going to use it any time soon best to lower its charge a little. Maybe take out 10% by Ah. If going to store for weeks to months, take out about 1/3rd of its capacity or so.

[White Lightnin']

How can the battery cells be fastened together in order to prevent vibrations from movement of the chair causing the connectors to break loose from the cells?

[emilevirus]

How can the battery cells be fastened together in order to prevent vibrations from movement of the chair causing the connectors to break loose from the cells?

Mine came with lock nuts, no problem so far.

[shirley_hkg]

Duct tape.

I add small bits of double-side adhesive tape between cells too.

Only use flexi inter-connects, eg. short wire with lugs.