I live in Perth, Australia where the sun is always shining! I have a rooftop solar system with 6.5kW of panels feeding the house via a 5kW 3phase Fronius inverter. I export surplus power to the grid and get paid 7c/kWh for this, versus 30c/kwh for buying grid power.
My mate has recently installed a Tesla powerwall which means he can store power instead of exporting it. However, the cost of the power wall has increased dramatically (about AUD$16,000 plus installation) and hence it cannot be justified on economics.
I was wondering how easy it is to build my own powerwall. I have already have some experience having recently updated an electric motorcycle to 48V LiFePO4 power - increasing the range to about 150km per charge. I incorporated a 150A BMS.
I am pretty familiar with the battery and BMS side of things. I am thinking of using 16 x 3.2V x 205Ah LiFePo4 cells giving a maximum theoretical capacity of 10.5kWh. The charging side is presumably straight forward, I could hopefully use my existing 48V 25A charger for this purpose, giving a charge time of about 8 hours during the sunny part of the day 8.00-16.00.
I am also familiar with BMS functionality and battery protectors, etc.
I will also need a very large inverter. However, I notice that a Tesla powerwall only has a 5 kW inverter, which means that it is not able to power any where near as much as the grid can (3 phases x 240V x 23A each = 16.5kW). However, I guess it is possible to make do with about 5kW.
The other issue is how it would be connected to the house power and whether it would be allowed under the Australian regulations. Presumably I would have to disconnect from the grid and connect to the DIY powerwall instead?
Currently I have an old 48V 16 cell LifePO4 battery pack with a capacity of about 3kWh powering a 3000W inverter. It has a 100A BMS fitted. In power outages, I simply connect the TV, coffee machine, computer, etc to the inverter via an extension lead and power board. Simple!
Is it worth trying to build my own powerwall/
Cheers
My mate has recently installed a Tesla powerwall which means he can store power instead of exporting it. However, the cost of the power wall has increased dramatically (about AUD$16,000 plus installation) and hence it cannot be justified on economics.
I was wondering how easy it is to build my own powerwall. I have already have some experience having recently updated an electric motorcycle to 48V LiFePO4 power - increasing the range to about 150km per charge. I incorporated a 150A BMS.
I am pretty familiar with the battery and BMS side of things. I am thinking of using 16 x 3.2V x 205Ah LiFePo4 cells giving a maximum theoretical capacity of 10.5kWh. The charging side is presumably straight forward, I could hopefully use my existing 48V 25A charger for this purpose, giving a charge time of about 8 hours during the sunny part of the day 8.00-16.00.
I am also familiar with BMS functionality and battery protectors, etc.
I will also need a very large inverter. However, I notice that a Tesla powerwall only has a 5 kW inverter, which means that it is not able to power any where near as much as the grid can (3 phases x 240V x 23A each = 16.5kW). However, I guess it is possible to make do with about 5kW.
The other issue is how it would be connected to the house power and whether it would be allowed under the Australian regulations. Presumably I would have to disconnect from the grid and connect to the DIY powerwall instead?
Currently I have an old 48V 16 cell LifePO4 battery pack with a capacity of about 3kWh powering a 3000W inverter. It has a 100A BMS fitted. In power outages, I simply connect the TV, coffee machine, computer, etc to the inverter via an extension lead and power board. Simple!
Is it worth trying to build my own powerwall/
Cheers