How long does your Base battery last during an outage?
How long your Base battery lasts depends on four main factors:
How much power you use: This is the most important factor. A battery stores a fixed amount of energy when the grid is down, so running high-usage devices (like A/C or laundry machines) will shorten backup time, just like a bigger water hose will drain a bucket more quickly. Reducing your power usage will extend it. We deploy larger batteries than the typical market size so that your home can stay powered longer.
Battery charge at the start of an outage: Backup time depends on how charged your battery is when the power goes out, which can fluctuate due to our grid-balancing operations. You should always have at least 5 hours (if you have a single battery) or 10 hours (if you have two batteries) of backup at low energy usage during normal operations.
Additional generation sources: Base batteries integrate with solar panels or generators, which can extend your backup duration during an outage.
In the Base Power app, you can see your battery system's estimated backup duration.
The estimated duration is based on your real time energy usage. You will also be able to see how much backup time your battery would provide if you reduced electricity usage. If you have two batteries, the estimate will reflect both batteries combined.
The Base Power team believes that showing estimated duration at both current and low usage better prepares members for outages.
If you have push notifications on in the app, you'll get notified when your power goes out so you can monitor your battery status and usage. We always recommend turning off high-usage appliances to extend your backup time.
97% of outages in Texas are less than 2.5 hours long.
Here is a breakdown of how energy usage typically translates to backup duration for our single 39.2 kWh battery:
Low usage (750 W from fridge, freezer, lights): 22-36 hours
Average usage (1.5 kW from typical appliances, some A/C): 12-18 hours
High usage (4 kW from heavy appliances, more A/C): 4-6 hours
Very high usage (8 kW from heaviest appliances like electric heaters or dual A/C units): 2-3 hours
For our 25 kWh battery systems, these backup durations would be slightly lower:
Low usage: 15-24 hours. With two batteries, 30-48 hours.
Average usage: 8-12 hours. With two batteries, 16-24 hours.
High usage: 3-4 hours. With two batteries, 6-8 hours.
Very high usage: 1-2 hours. With two batteries, 2-4 hours.