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Home Battery Warranty And Degradation
Every battery loses some capacity as it ages. A warranty tells you how much loss the maker will tolerate before it steps in. The details are in the fine print, so this guide shows what to look for.
What Degradation Means
Capacity is the energy a battery can store. Over years of charging and discharging, a battery holds a bit less. A warranty that promises 70 percent retention at 10 years is saying the battery should still hold at least 70 percent of its original rated energy at the 10 year mark, under the stated conditions.
Examples From Published Warranties
- Tesla Powerwall 3: the US warranty lists 70 percent energy retention at 10 years, with unlimited cycles for solar self consumption, time based control, and backup use, and a throughput limit stated for other uses. The warranty also says Tesla may not be able to honor the full ten years if the unit stays offline for an extended period or is not registered. Source: Tesla Powerwall Limited Warranty (USA).
- Enphase IQ Battery 5P: a 15 year limited warranty, up to 6,000 cycles. Source: Enphase IQ Battery 5P listing.
- FranklinWH aPower 2: 15 years or 60 MWh of throughput, as announced by the maker. Source: FranklinWH aPower 2 announcement.
Terms To Look For
| Term | What It Means For You |
|---|---|
| Retention percentage | The share of original capacity the maker promises at the end of the term. |
| Cycle limit | A cap on full charge and discharge cycles. A heavy daily user can reach it sooner. |
| Throughput limit | A cap on total energy moved through the battery, shown in MWh. |
| Conditions | Requirements such as connectivity, temperature, installation by a certified installer, or limits on use. |
| Remedy | Repair, replacement, or refund, and who pays for labor. |
Practical Steps
- Get the actual warranty document, not a brochure summary.
- Check who pays for removal and reinstall labor if a unit is replaced.
- Ask what happens to the warranty if your installer goes out of business. See this guide for solar owners for how that plays out on the solar side.
- Keep your serial numbers, install date, and commissioning report in one folder.
- If you cycle the battery hard every day, compare cycle and throughput caps, not just years.
See Powerwall Versus Enphase Versus Franklin for spec comparisons and Home Battery Cost for pricing context.
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Use our checklist to compare installer quotes side by side. In Texas, see txhomebattery.com for local outage, utility, and incentive guides.
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