Sump pumps are one of the most boring parts of home ownership. Until that one storm comes and suddenly they’re interesting.
After losing power one time this summer, I got paranoid and decided to build a battery backup. Home Depot had the basement watchdog systems, but they seemed high maintenance and I wanted something that would let me be lazier. I went with a LifePo4 battery system, that will (hopefully) get me 10 to 15 years. The battery charger has a float/storage mode so it can stay on 24/7. Doing some test runs, I think I can get about 400 cycles out of the battery before it hits 0%. I added some additional safety features (DC circuit breaker, GFCI with auto-on, Lithium fire extinguiser, etc), and added some battery powered lights and a basket of hand tools, so in the event the power goes out in the dead of night, something goes wrong, and I have to get my feet wet, everything is there ready to go.


Am I not understanding something, why not just a UPS?
A UPS with that capacity would likely be 5-10x the cost of what OP built.
Thanks for chiming in because yes - the answer is “money”.
Parting out the system as individual components saved me a ton of it. In addition, it will be easy to identify and replace problematic components if and when they fail (for a fraction of replacing a UPS that meets the power requirements).
How much did this cost you? Just trying to compare a my Ecoflow which I use for a network UPS. It’s got a capacity to run steady for an hour or two I think.
For the core backup system with the battery, inverter, ATS, charger, circuit breaker, etc. Right around $900 or so.
I’ve calculated it to do 400ish cycles. So if my pumps turn on every 5 minutes, it’ll go about 33 hours.
Sounds pretty good. I’d spend that much for that length of operating time