What "5.0 kWh Usable" Means on an Enphase IQ Battery 5P: Reserves, Round Trip, One Unit per Circuit and 6,000 Cycles
Summary
Enphase lists the IQ Battery 5P's total and usable capacity as the same 5.0 kWh, and then qualifies it: the usable figure includes a 2% safety-critical limit held back for a long outage and a further 3% kept for the battery's own electronics at night. Getting 5.0 kWh out takes more than 5.0 kWh in: the data sheet gives 90% AC round-trip efficiency and 96% DC. Each unit delivers 3.84 kVA continuously, peaks at 7.68 kVA for three seconds, and must sit alone on a 20 A branch circuit. The warranty runs 15 years or 6,000 cycles to more than 60% capacity, which is about 1.1 cycles a day over the full term.
The capacity lines, read with the footnote
| Line | Figure | Qualification |
|---|---|---|
| Total capacity | 5.0 kWh | |
| Usable capacity | 5.0 kWh | includes a 2% safety-critical limit for a long-duration grid outage; a further 3% is maintained for battery electronics at night |
| AC round-trip efficiency | 90% | about 5.6 kWh of AC in for 5.0 kWh out |
| DC round-trip efficiency | 96% |
Our 5.6 kWh figure is simple division; Enphase publishes a separate technical brief on usable capacity that the data sheet points to.
Power, per unit
| At 240 V | At 208 V | |
|---|---|---|
| Continuous | 3.84 kVA | 3.33 kVA |
| Peak | 7.68 kVA for 3 seconds; 6.14 kW for 10 seconds (product page) | |
| Rated output current | 16 A | |
| Peak output current | 32 A (3 s), 25.6 A (10 s) | |
| Motor start | up to 48 A LRA | |
| Circuit | one unit per 20 A branch circuit, single-phase |
Six grid-forming microinverters are built in, which is why the unit is rated in kVA and why backup needs the IQ System Controller 3 or 3G. Our guide on starting an air conditioner compares the 48 A LRA figure with Powerwall 3's.
Weight, temperature and placement
Lifting weight is 66.3 kg (146.1 lb) and installed weight 78.9 kg (174 lb). The ambient range is −20 °C to 50 °C, or to 55 °C depending on the line of the sheet, with full performance while charging between 15 °C and 45 °C and while discharging between 0 °C and 50 °C. Enphase's placement guidance names a non-habitable indoor space such as a two-car garage or an outdoor location within the range.
6,000 cycles over 15 years
6,000 cycles divided by 15 years is 400 a year, about 1.1 a day. A battery that cycles once daily for self-consumption uses the cycle allowance at roughly the pace the years run out, so the two limits arrive together; one that mostly waits for outages reaches 15 years with most cycles unused. The warranty threshold is more than 60% of capacity, lower than the 70% and 80% end points on the portable units in our other guides.
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Sources
We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.