Figured I'd start a new thread since I have shifted focus from my initial plan to build a Golf Cart battery to building a small power wall. I'd like to have a clear game plan from the beginning and hopefully, a few members can offer some guidance.
My plan is to first build a ~ 13kWh power wall and then add solar, then hopefully expand the powerwall. Why that rating? Because that is about equivalent to a Tesla powerwall and I want to see how much a DIY version costs.
Here's what I'm thinking, so please feel free to comment on where I'm off track or whatever.
Cells: Planning on harvesting ~ 1400 cells from the ring packs from battery clearinghouse. These are ~3000 mAh each. I've harvested about 100 so far and only managed to destroy one cell in the process and the 33 that I've run through my opus and liitokala testers have all tested better than advertised. I haven't done a real IR check yet, as I'm waiting on my YR1035 to arrive still.
Inverter: I really like the review David Poz did on the Growatt SPF5000ES.
Sun: I live on the Texas Gulf coast and get 4.5+ avg hrs of direct sun daily. I've got two massive rooflines, one that faces south and the other facing west, so I have plenty of options for good sun.
What I don't quite understand at this point is what size to build the packs, especially to make the system scalable, as well as what to do about the BMS solution. For the golf cart battery I was originally planning, the big, expensive BMS setups didn't make sense, but it may make more sense for a power wall. I want safety to be the top concern so I want to use the cell level fusing strips that battery hookup sells.
I guess the packs need to be in 14s configuration but how many should be in parallel per pack is something I have no idea about the best approach. At the end of the day, I'm doing this because it's interesting to me so I want to learn along the way, I just don't want to make a bunch of expensive mistakes in the process
My plan is to first build a ~ 13kWh power wall and then add solar, then hopefully expand the powerwall. Why that rating? Because that is about equivalent to a Tesla powerwall and I want to see how much a DIY version costs.
Here's what I'm thinking, so please feel free to comment on where I'm off track or whatever.
Cells: Planning on harvesting ~ 1400 cells from the ring packs from battery clearinghouse. These are ~3000 mAh each. I've harvested about 100 so far and only managed to destroy one cell in the process and the 33 that I've run through my opus and liitokala testers have all tested better than advertised. I haven't done a real IR check yet, as I'm waiting on my YR1035 to arrive still.
Inverter: I really like the review David Poz did on the Growatt SPF5000ES.
Sun: I live on the Texas Gulf coast and get 4.5+ avg hrs of direct sun daily. I've got two massive rooflines, one that faces south and the other facing west, so I have plenty of options for good sun.
What I don't quite understand at this point is what size to build the packs, especially to make the system scalable, as well as what to do about the BMS solution. For the golf cart battery I was originally planning, the big, expensive BMS setups didn't make sense, but it may make more sense for a power wall. I want safety to be the top concern so I want to use the cell level fusing strips that battery hookup sells.
I guess the packs need to be in 14s configuration but how many should be in parallel per pack is something I have no idea about the best approach. At the end of the day, I'm doing this because it's interesting to me so I want to learn along the way, I just don't want to make a bunch of expensive mistakes in the process