Tesla Powerwall › Problems

Powerwall 2 holds far less energy than its rated 13.5 kWh

A Powerwall 2 holds far less energy than its rated 13.5 kWh, often after several years in service. This page covers how to measure what it really holds, what to check first, and the cause behind it.

What to check first

1. The Powerwall 2 warranty guarantees at least 70% of rated capacity for 10 years. Below that line, a warranty claim applies.
2. Check the degradation figure in a monitoring app such as Netzero, which pulls data from the Powerwalls and costs about $7 a month. A screenshot of it has supported a warranty claim, though Tesla checks the figure itself.
3. To measure it yourself: the day before good sun, set the reserve to zero and let the batteries drain to zero, then switch to backup-only and let them fill. The total the system reports is an independent measure of capacity.
4. Run two full discharge and recharge cycles and keep a record of both. Two cycles showing under 70% of rated capacity is the evidence to file with a claim.
5. Tesla goes by its own measurement. An owner's test came to about 63% of original capacity, but Tesla measured 74% and declined to act because that is above the 70% line.
6. If your figures show under 70%, file the warranty claim through your installer, and ask for escalation to Tesla Tier 2 if it is denied. Claims have taken from a couple of months to about a year.