Greetings everyone,
Joined here yesterday and super excited to be part of this community.
I have just started my project and I am not quite sure how to set up my packs because I have a somewhat different situation with my cells.
So:
So here is my actual question,
Should I just start building with the hoverboard cells, create packs with identical cells? Im thinking 14 packs of like 115cells (14s115p) - 170cells in parallel (170 if im getting another 40 of the hoverboard packs)? That would still total a pack capacity of 12kWh (correct me if im wrong). As these cells are essentially close to identical in terms of capacity, cycles and specs Im thinking I might be able to not bother with a bms, but let me know what you think please These packs should last virtually forever, compared to laptop cells atleast.
Then as I get more and more good laptop cells I can expand and build packs that only consist of laptop cells and create another 14 packs that I can hook up in parallel again under the hoverboard packs. How should I setup these packs? mix and match high and low capacities like some are recommending or do what HBpowerwall is doing and build packs that consist of only certain capacity cells?
OR
Should I build packs with a combination of laptop cells and the hoverboard cells, mixing and matching the packs as I go, create larger packs of lets say 160p-200p. Kind of would make sense im thinking but then again im mixing relatively new cells with old ones where I dont know the lifespan of. I might create tons of extra work if I have to start exchanging old cells in the packs.
Thanks for the help everyone, any suggestions would be welcome.
J
Joined here yesterday and super excited to be part of this community.
I have just started my project and I am not quite sure how to set up my packs because I have a somewhat different situation with my cells.
So:
- I have 1600 cells that are all from hoverboards. It was 80x 36v 4.4aH packs. The cells are Samsung ICR18650-22P, all produced November 2015 and all in working order. Every pack measured between 32-41V, with about 50 being at36V so I lets just say I was real happy when I got these. I am in the process of taking these apart. I am testing only 2 cells from each pack at the moment to see their capacities (is this enough? dont know why they would be very different...?), my BT-C3100 is measuring most at 2250-2400mAh at the moment, subtract roughy 13% from these figures due to the inaccuracy and Im left with cells between 2000 and 2100mAh. Pretty perfect if you ask me.
- Secondly I have about 1400 cells from laptop batteries. I am testing these but as you all know this process takes a lot longer.
So here is my actual question,
Should I just start building with the hoverboard cells, create packs with identical cells? Im thinking 14 packs of like 115cells (14s115p) - 170cells in parallel (170 if im getting another 40 of the hoverboard packs)? That would still total a pack capacity of 12kWh (correct me if im wrong). As these cells are essentially close to identical in terms of capacity, cycles and specs Im thinking I might be able to not bother with a bms, but let me know what you think please These packs should last virtually forever, compared to laptop cells atleast.
Then as I get more and more good laptop cells I can expand and build packs that only consist of laptop cells and create another 14 packs that I can hook up in parallel again under the hoverboard packs. How should I setup these packs? mix and match high and low capacities like some are recommending or do what HBpowerwall is doing and build packs that consist of only certain capacity cells?
OR
Should I build packs with a combination of laptop cells and the hoverboard cells, mixing and matching the packs as I go, create larger packs of lets say 160p-200p. Kind of would make sense im thinking but then again im mixing relatively new cells with old ones where I dont know the lifespan of. I might create tons of extra work if I have to start exchanging old cells in the packs.
Thanks for the help everyone, any suggestions would be welcome.
J