Hey guys-
Here’s a photo of me charging the first time…
Is there reason to be concerned by the discrepancy between Cel 10
And the others??
I guess my fear is that I was using a wide nickel
Tab- I’m fairly certain that all spot welds turned out ok- this is a 12s9p
Is that variability within normal limits?
How would I know if one of my cells failed to spot weld appropriately?
Thanks
P
Fudge- getting a little worried! Please help!
How many times have you cycled that battery? What cells are you using? Are they all the same cells form the same batch? Were they new cells or used cell? When you plug in your charger does [balancing] indicate that its balancing?
Hey skyart
12s9p 50e
It’s actively charging now
Same batch all new- all started from same amount of volts
Should I disconnect???
Is this the first time you are charging? You likely have some bad welds on the one pgroup that is charging faster
Indeed it is, yes
No, so once it gets to 4V/cell it will begin to balance and bleed energy from the highest voltage cell. If it gets low when you discharge it then you have a problem but I’d start by letting the BMS do it’s thing
Come cells have a different voltage (in theory you wanna check them all first so this doesn’t happen, but it’s probably okay), so you need to let the BMS try it’s best and go from therr
If a group charges and discharges faster it’s a sign that one of the cells isn’t making full contact so the capacity of the group is lower, in that case you want to extract the group the redo all the welds (I’d use a new piece of nickel and grind the nubs on the cell flat with a Dremel
Is it possible one of my welds isn’t solid though? And maybe that’s why it’s charging one faster than the other? Does that make sense?
This is likely the case, if they were all same voltage when you started, you probbaly have a bad weld on one or two of your cells in that pgourp. Recently had the se thing happen
As if it’s seeing all the packs as a 9 p and maybe one has a messed up weld and is charging rapidly bc it’s acting as an 8p?? Or would I experience other issues?
Exactly, if the connection isn’t good enough. That one group could infact be 8p. When I removed my group, I found cold welds on the negative side of one cell. They simply broke loose and my 5p was now a 4p
Hmm - ok- so you think take it apart and assess?
I think that would be best. I rode my board for a few cycles to make sure it wasn’t a weird balance issue. But this could be dangerous. If for some reason the loose cell starts making connection again you could damage it by over charging or over discharging it, depending on the state of charge of the rest of that group
This is one of the reasons I only build with smart a smart BMS, you can immediately trouble shoot your pack. And not have to wonder its good or not.
Ok- and just so I understand, cell 10
Would be 2 from my main negative ?
I think so. But use a voltage meter to confirm which group is the one with the higher voltage.
Smart-
Also, when I let It rest, it does this…
Gets closer to normal- ehh fuck it- I’ll take it apart and see thanks guys- the others look ok though?
The others look ok. Yeeah totally up to you, but I would take it apart
