I am building my first powerwall for a friend. It is a 14S24P using Boston Power Swing 5300 cells and the Batrium BMS system.
Here is how I am building the packs for this small powerwall. Since this is for a home application for safety I wanted to fuse at the cell level. I actually went with 6.3A fuses. They should blow about 13A or a dead short and as such provide what I want ....which is protection against a dead short or some other catastrophe ....and not impede current in normal use. This is going to be a 14S24P powerwall with Boston Power Swing 5300's, all new batteries and the Batrium BMS. It is meant to be able to be moved around if need be and for all individual parallel packs to be able to be removed in case of any problems with that pack. Additionally if I want to expand it I can just add packs in parallel at the bottom of it and not have to invest in more Batrium longmons. Regular continuous current has been analyzed to be 60 amps with possible spikes of 150 amps so this configuration should handle it with no problem.
I fabricated brackets out of steel and then wrapped them with silicone tape to prevent shorting with the Batrium Longmons that will be mounted on the top of the batteries with ziptie holders. This is so the packs can be mounted vertically on a wall. I am also building a box for all of them and the batrium. The box is painted with intumescent paint which is supposed to form a foam barrier and be at the very least a fire retardant in case something like that might happen. There is 1/4" ABS plastic in between each pack. I think I may cover the front of the box with 1/4" acrylic and have ventilation ports on the sides of the boxes and probably hook up some fans but I really don't expect this pwall to be experiencing significant heat issues as the normal load will only be about 60 amps. The intumescent paint is by Firetect and you can check it out here: https://www.firetect.com/
The packs are spot welded to the batteries on the positive side with 1.5MM pure nickel which is then soldered to the busbars. The negative side has the 6.3 amp fuses soldered to the battery as well as the busbar. I tried a setup where I spot welded nickel tabs to the negative side of the battery then soldered the fuses to it and the busbar but it was just too messy for my taste so I went with just soldering on the negative side. My spot welder is the Kweld and good welds can be accomplished at as little as 15 joules with it.
I want to implement a shunt trip breaker with this powerwall but still need to either buy the expansion board ....or figure out how all that works with just the mosfets on the Watchmon4.
That's it for now .....comments are always welcome.
Richard
Here is how I am building the packs for this small powerwall. Since this is for a home application for safety I wanted to fuse at the cell level. I actually went with 6.3A fuses. They should blow about 13A or a dead short and as such provide what I want ....which is protection against a dead short or some other catastrophe ....and not impede current in normal use. This is going to be a 14S24P powerwall with Boston Power Swing 5300's, all new batteries and the Batrium BMS. It is meant to be able to be moved around if need be and for all individual parallel packs to be able to be removed in case of any problems with that pack. Additionally if I want to expand it I can just add packs in parallel at the bottom of it and not have to invest in more Batrium longmons. Regular continuous current has been analyzed to be 60 amps with possible spikes of 150 amps so this configuration should handle it with no problem.
I fabricated brackets out of steel and then wrapped them with silicone tape to prevent shorting with the Batrium Longmons that will be mounted on the top of the batteries with ziptie holders. This is so the packs can be mounted vertically on a wall. I am also building a box for all of them and the batrium. The box is painted with intumescent paint which is supposed to form a foam barrier and be at the very least a fire retardant in case something like that might happen. There is 1/4" ABS plastic in between each pack. I think I may cover the front of the box with 1/4" acrylic and have ventilation ports on the sides of the boxes and probably hook up some fans but I really don't expect this pwall to be experiencing significant heat issues as the normal load will only be about 60 amps. The intumescent paint is by Firetect and you can check it out here: https://www.firetect.com/
The packs are spot welded to the batteries on the positive side with 1.5MM pure nickel which is then soldered to the busbars. The negative side has the 6.3 amp fuses soldered to the battery as well as the busbar. I tried a setup where I spot welded nickel tabs to the negative side of the battery then soldered the fuses to it and the busbar but it was just too messy for my taste so I went with just soldering on the negative side. My spot welder is the Kweld and good welds can be accomplished at as little as 15 joules with it.
I want to implement a shunt trip breaker with this powerwall but still need to either buy the expansion board ....or figure out how all that works with just the mosfets on the Watchmon4.
That's it for now .....comments are always welcome.
Richard