18650 cells holder 7s5p or 5s7p 35 cells

thingiverse

Human: 35 Cell Holder for a DIY Powerwall with Solar Controller. Use a 5x7, 5p7s or 7p5s configuration to make your own power wall battery. With 2000mAh cells, you will achieve a 24V, 250Wh battery in the 7s5p setup. Four of these batteries put together equal one kilowatt-hour of energy. WARNING: It is highly recommended to use a BMS (battery management system) with 18650 cells because they are not stable when overcharged. Don't risk it if you don't know what you're doing. The standard version has 19mm holes, but for better fitment, print it at 101% (19,2mm). The scaled file is available in the files section. UPDATE V1.0 May 17th, 2019: I've made some improvements and now release v1.0, the first fully usable version. I added holes to hold busbars with zipties and four bigger holes for M5x70 screws that compress the pack. Since I don't have any M5x70 screws at the moment, I'm using long zipties as shown in the pictures. It works well. Print it between 98% and 102% to find the correct fit. You can test this with the V1.0 test part, a 2x3 cells holder that lets you check cell fit before printing the big part. Another version is coming soon when I make my second pack with two little holes instead of one for busbar placement between rows. Stay tuned! Join Jehu Garcia's Facebook group if interested in DIY Powerwalls: https://www.facebook.com/groups/jehusDiYPowerwalls/