Building your own home battery is relatively simple and will end up costing between 1/3 and 1/2 of what it normally costs to purchase a ready-assembled home battery.
Why Do I need a Home Battery?
1) If you have solar panels, these will produce free, clean, environmentally-friendly energy each day. However to continue to use this free power after the sun has set, or for periods when power use exceeds solar production, a home battery allows you to smooth out the peaks and troughs.
2)If you want to make money out by buying low-cost electricity at night (available in the UK for as little as 3.4p/kWh) and selling it back at between 12-25p/kWh. Even without PV, at 12p/kWh it is possible to totally offset the cost of your electric bill.
3)To provide a back-up power solution for use during power cuts. Even very recently, some areas of the UK have been subject to long power cuts – often in excess of 3days and sometimes as long as two weeks – due to severe weather or flooding. In these situations, having a backup means that you can continue to charge mobile phones/use the internet/keep fridges and freezers cold.
What is the lifespan of a Lithium home battery (Lifepo)?
Obviously, if you stress your battery by over-discharging or leaving it discharged for a prolonged period, you will shorten the lifespan. But a typical home battery cycled between 100% and 20% will last at least 6000cycles. With a well made battery cabinet, that maintains pressure on the sides of the cells, you could extend this to 8000 or even 12000cycles. Even at the lower end – ie 6000 cycles, that is equivalent to 16.5years of daily discharge!
What size battery do I need?
This is obviously down to your particular application, but as a rough guide, an average house uses 10kWh/day of electricity. If you heat your home with a heatpump, then you might use 30-60kWh/day during the winter. Decide whether you want to store enough power that you never need to buy peak rate electric, or whether you just want to reduce your peak-rate consumption. To avoid shortening your battery lifespan, you should aim to charge to 100% and discharge to no less than 20% – so batteries should be oversized by at least 20%.
Typically, until very recently, most houses were fitted with no more than 10kWh storage, due to the high cost of lithium batteries. However, with the advent of DIY batteries, the cost has plummeted, and many people are now fitting 16-64kWh systems
Cost-effective Home Batteries are now here!
10 Seconds to Midnight now provides cost-effective battery components and battery kits for DIY- assembly in the UK. Assembly is relatively straightforward and has the huge advantage that each individual component is relatively light – under 6kg, making it easy to carry inside and assemble pretty much anywhere. Compare this to a pre-assembled 16kWh battery which will weigh in at just under 100kg – not the sort of thing you want to carry in from the kerbside to it’s installed location!
Downloads
Assembly Instructions for our Battery Cases
Recommended JK BMS settings
LiFePO Cell Datasheets
Datasheet for CORNEX 314Ah Grade A LiFePO Cell
Datasheet for DESAY 314Ah Grade A LiFePO Cell
Datasheet for Trina 314Ah Grade A LiFePO Cell