Thanks for the advice. I am using the Apex Smart BMS and app im using it with is the Xiaoxiang BMS, whcih apparently contains: “Balance wiring harness…”. I cant see anything specific in teh app that says ‘set to balance’, or anything similar sounding, are you famililar with this app by any chance?
EDIT: Jusrt seen this option here, guessing I need to set the balance mode to static to follow your suggestions?
I apprecaite the offer of help, but im in the UK, so am going to go with Mooch’s advice and charge it and try and set it to balance in the BMS and just leave it. Btw, is there anything in my BMS settings that need tweaking? (I posted them above).
Looks good to me, the current used to balance is usually very small so be prepared to watch it for a few days. Im not familiar with the spec on that bms so I don’t know if it has active balancing or resistive balancing, maybe someone with direct experience can chime in. If it is resistive the bms may need to discharge all high cells in order to bring the low group up so it may get warm… but never hot. Remember to charge it in a fire safe, and preferably environmentally controlled place. And don’t leave it unattended, only charge it when your home, safety safety bla bla bla. Good luck, hope it recovers for you
I got P42As from them for $4.50 a cell a couple of months ago. I prefer that deal. You usually have to buy pretty big bulk to get close to that deal though. I don’t have the experience to know how true it is, but people around here seem to think Samsungs start having issues pretty quickly sometimes.
Regarding cutting your own nickel. I bought a 30mm x 0.2mm roll which covers the tops of a double stack, but I then need another piece attached for the bend tab. Do i then weld another piece of nickel on to make the tab? What joule setting is required for this since it would be 2 pieces of 0.2mm nickel welded together? Is this how this is supposed to be done.
I couldn’t find any 50mm wide so I could just have 1 solid piece of nickel instead of doing this.
Every welding setup is different, but generally nickel-to-nickel takes more beans than nickel to cells (cell cans are steel). You should experiment till you get good strong results.
The general rule of thumb used around here is that each weld is good for ~5 amps, so the usual six welds (three pairs) per cell connection is good for ~30A. It should be pretty safe to extrapolate that out to the full pack design current.
Hee, In trying to charge my battery pack, but it doesn’t charge to 42V (10S). It stops around 40V and the charger will go green-red-green-red as you can see in the video. What should I do?
Could that be? It’s the first time I charged that battery I do have a BMS (unfortunately not a smart one) and when I made the battery al the groups had the same voltage…
If it happens at around 40V, the pack is not fully charged, but one p-group is hitting the voltage cutoff.
How it goes:
All p-groups are below 4.2v
Plug in charger, light is red
Charger voltage is applied and voltage on each p-group goes up a little.
Highest p-group hits voltage cutoff, charging voltage is disengaged, light is green.
With voltage disconnected, all p-group voltages go to the resting voltage and decrease a little bit.
All p-groups are below 4.2v
The charging hysteresis being too narrow causes this loop.
Had the exact same behavior on the small Daly BMS and a worn out battery.
It wouldn’t really happen on a brand new pack, yours might have a bad spot weld.
You’ll have to probe the voltage on each p-group at the JST connector.
I suggest a BMS that provides feedback on p-group voltages.
