Home batteries, on their own datasheets
A battery does not make your array produce more. It moves production from the middle of the day, when the house is empty and the export price is low, to the evening, when it is neither. Everything below is about how much it can move and at what loss.
Two systems are covered here in full. Both are lithium iron phosphate, both are rated for outdoor installation, and each one only works behind its own manufacturer's inverter - which is usually the constraint that decides the choice.
The systems
Side by side
The full specification of both, from their manufacturers' datasheets. Usable capacity is the figure to compare, not total: the difference is reserve the battery keeps to protect its own life.
| Specification | Enphase IQ Battery 5P | SolarEdge Home Battery |
|---|---|---|
| Total capacity | 5.12 kWh | 10 kWh |
| Usable capacity | 5.12 kWh | 9.7 kWh |
| Continuous power | 3.84 kW | 5 kW |
| Peak power | 7.68 kW | 7.5 kW |
| Round-trip efficiency | 89% | 94.5% |
| Chemistry | LFP (Lithium Iron Phosphate) | LFP (Lithium Iron Phosphate) |
| Coupling | AC-coupled | DC-coupled |
| Requires | Enphase IQ microinverters | SolarEdge Home Hub inverter |
| Product warranty | 15 years | 10 years |
| Warranted cycles | 4,000 | not specified |
| Maximum units | 4 | 3 |
| Weight | 54 kg | 104 kg |
| Dimensions | 595 x 305 x 280 mm | 730 x 440 x 220 mm |
| Ingress protection | IP55 | IP55 |
| Whole-home backup | Yes | Yes |
Manufacturer figures. Round-trip efficiency is measured at the battery terminals and does not include the inverter losses either side of it, so the number a system delivers is lower than the number on the cell.
How to read these figures
Total capacity is what the cells hold; usable is what the system will give you. The gap is a deliberate reserve that stops a deep discharge shortening the battery's life, and it is the figure a quote should be built on.
A DC-coupled battery charges straight off the array, which is why its round-trip efficiency is higher. An AC-coupled one converts twice and loses a few points, but it does not care what produced the electricity - and it can be added to an array that is already built.
Peak power is a few seconds of motor start-up. Continuous power is what the battery will actually hold, and it is what decides whether the house runs on it or only the fridge does.