I am hoping that if you are looking at this you have your hands on some Tesla 21700 cells. If not, you can get 21700 cells from Queen Battery. They are 4000 mah cells at 3.7 volts for 14.8 watt hours per cell.
This is a Fencepost Power Wall design. The Cap fits over a chunk of 5″ plastic fencepost tube.
The Bloc holds 50 21700 cells. At 14.8 watt hours a cell, that is 740 watt hours. Put 15 in series for a 60 volt 11.1 KWH Power Wall. Double the cells with a “DoubleDangler” for a 22.2KWH Power Wall. An Active Balancer is attached to the cap, so a BMS is optional. Attach any number of Blocs in series and the balancers will move the power from the high voltage Blocs to the low voltage Blocs, 24/7 balancing the battery at the top, the middle the bottom….
Included is a Cap for a 5″ Fencepost tube with a voltage gauge and an Active Balancer as shown. The 32P1S BatteryBloc for 26800 cells is included. A screw on bottom cap is included.
Not included is the 5″ Fencepost. You can get this at Lowes or Home Depot. Figure about eleven inches for each parallel group. You can sit these on a shelf either upright or flat. You can hang them from the wall as well using Super Strut.
Cut the strut into 4″ lengths and bolt to the back top of the fencepost tube. Attach a length of SuperStrut to the wall studs, and hang the Blocs from it. Bolt the Blocs together in series.
Here is a back-of-the-envelope calculation of the costs for a 60 volt, 15S50P Power Wall making 11.1 KW.
(15) 21700 Power Wall Caps and Blocs $990.
(750) 21700 cells from QB $2295 delivered.
Fencepost tube: $52.00
Super Strut: $20.00
So that is $3357, round to $3400 for a 11.1kwh repairable & rebuildable PowerWall with active balancing. ($306 a kwh)