Castaway Camper
New Member
- Joined
- Sep 15, 2021
- Messages
- 18
Just completed this build for my off grid camp along the James River in Virgina. I checked in with a few recommended prismatic cell vendors that I found on this forum and decided to go with SQO (Shenzhen Qishou Technology) as seen on "Off Grid Garage" videos. The total price delivered including Pay Pal fee came to $2,650. One of the main reasons I selected this supplier is that Amy Peng of SQO stated that these 304Ah EVE cells were only a week away from US warehouse in California, I'm not terribly patient. Ordered on 12-13-21- received on 12-27-22. All cells looked visually in top condition, they were packaged 2 to the box, with the "pool noodle" type foam, 1" around the perimeter 3" thick top and bottom. The cardboard was double thick and very well taped, just a couple dings on the packaging.
The BMS used is the 16S 100amp model from Overkill Solar, I also ordered some 2 gauge wire for the positive and negative leads, along with appropriate lugs to fit over the welded 6MM welded studs that the cells came with.
Wood working is one of my hobbies, so building a plywood box came as the easy option for housing this 215 pound beast. I used 3/4 finished cabinet plywood for the carcass and hardwood for the corners and lid/base trim, painted with aerosol Rust-O-Leum "Hammer finish" gray. It took a couple tries but I got the box perfectly sized to fit the cells snugly into place, having to apply slight pressure to push the last cell into place for each column. I selected this configuration because of specific space constraints, I modified a couple bus bars to join two locations where the cells are attached edge to edge, also made up a jumper with the #2 cable about 14" long to complete the entire series connections
The BMS from Overkill Solar is mounted to a bridge board using pocket screws on the edge for easy removal if needed, balance leads were cut to length and terminated with 1/4" shrink wrap insulated ring terminals. With this BMS there are three included temperature sensors. I was able to snake them down into the corners where 4 cells come together (just enough space to do so), they are spread out as evenly as possible. Two 1/2" holes were drilled in the box for main positive/negative leads to exit. With shrink insulation on the #2 cable at penetration it provided a very snug fit. The main positive and negative are terminated using 175 amp Anderson connectors hydraulically crimped on.
I took a chance and skipped the top balancing procedure as some have told me that with better cell suppliers the chances of receiving them balanced is getting better and better. So hooked up my cheap power supply and charging through the BMS with about 5 amps at 54.4 volts. This morning the voltage is 53.82 with a cell delta of 0.004 volts, I programed the BMS to start balancing earlier in the voltage range and with a finer delta of 0.007 volts (this programming will be returned to default once this initial balancing is complete). I'm not saying I'm home free yet as I realize the voltage can spread quickly as I near top SOC. We shall see... Anyway, I wanted to thank this forum for all the information I gained to even make this possible for me to do!
The BMS used is the 16S 100amp model from Overkill Solar, I also ordered some 2 gauge wire for the positive and negative leads, along with appropriate lugs to fit over the welded 6MM welded studs that the cells came with.
Wood working is one of my hobbies, so building a plywood box came as the easy option for housing this 215 pound beast. I used 3/4 finished cabinet plywood for the carcass and hardwood for the corners and lid/base trim, painted with aerosol Rust-O-Leum "Hammer finish" gray. It took a couple tries but I got the box perfectly sized to fit the cells snugly into place, having to apply slight pressure to push the last cell into place for each column. I selected this configuration because of specific space constraints, I modified a couple bus bars to join two locations where the cells are attached edge to edge, also made up a jumper with the #2 cable about 14" long to complete the entire series connections
The BMS from Overkill Solar is mounted to a bridge board using pocket screws on the edge for easy removal if needed, balance leads were cut to length and terminated with 1/4" shrink wrap insulated ring terminals. With this BMS there are three included temperature sensors. I was able to snake them down into the corners where 4 cells come together (just enough space to do so), they are spread out as evenly as possible. Two 1/2" holes were drilled in the box for main positive/negative leads to exit. With shrink insulation on the #2 cable at penetration it provided a very snug fit. The main positive and negative are terminated using 175 amp Anderson connectors hydraulically crimped on.
I took a chance and skipped the top balancing procedure as some have told me that with better cell suppliers the chances of receiving them balanced is getting better and better. So hooked up my cheap power supply and charging through the BMS with about 5 amps at 54.4 volts. This morning the voltage is 53.82 with a cell delta of 0.004 volts, I programed the BMS to start balancing earlier in the voltage range and with a finer delta of 0.007 volts (this programming will be returned to default once this initial balancing is complete). I'm not saying I'm home free yet as I realize the voltage can spread quickly as I near top SOC. We shall see... Anyway, I wanted to thank this forum for all the information I gained to even make this possible for me to do!