So i found a simular safety box to the Peli 1200 that i use for my current battery, this one has roughly the same base measurments but is a bit taller that allows me to stack two big clumps on top of eachoter, since i’ve starting to grow a bit tired of my petite 12s9p 30Q pack i bought this box and then realised i had to spend another 700$ on the cells, i already spent 15$ on the box so naturally i already stepped through the line of no retreat…
So after blowing another big hole in my wallet on e-skate related stuff i’m now sitting here with 200x Samsung 35E cells, 192 of those are going in to that box one way or another in the hopes of finally exterminate that range anxiety.
So to the subject. I perfectly well know how to build the packs themself, i however would need some advice on what configuration would be the safest since i’m starting to worry about my initial plan for the packs. That plan is to build 2x 12s8p packs, each with their own BMS (wired for charge only) and wire them up in parallel to get a 12s16p pack. The reason why i’m so keen on this idea is because that could allow me to remove one pack when i want to save weight or to power another board with. The idea is also to wire the charge ports in parallel so that i can charge both at one time with a single charger. At first i didn’t think of the potential risks that this might bring, such as
- Voltage differential that leads to high current transfer between the packs
- one BMS cancelling the charge current which leads to the previous mensioned issue (could be eliminated by disconnecting the discharge parallel connection during charging of course).
All the cells are at this point of course brand new and perfectly balanced to eachoter, however if i would end up using one pack more than the other and they are on different life cycles one could potentially have lower capacity than the other leading to a voltage differential during use.
So at this point i have two other ideas, those are either to feed each VESC with it’s own battery (would rather like to avoid this) and the other is to build 2x 6s16p packs wired in series, as stated i’m really liking the idea of 2x 12s8p in order to have some flexibillity. so the main question that i’d like some input on is how safe it would be to use 2x 12s8p with their own BMS’s or if i’m better of with one of the other options. I’m sure someone here has tried this previously, i know people use LIPOS in parallel with no issues.
Cheers - Jens