Another alternative is a water powered backup pump. They use the municipal drinking water supply to syphon the sump water out. I have one and it pumps just as fast as my electric pump. No need to worry over a battery running down.
Liberty Pumps SJ10 1-1/2-Inch Discharge SumpJet Water Powered Back-Up Pump - 1.5 Inch, Gray https://www.amazon.ca/dp/B0013H94MO/ref=cm_sw_r_cp_api_glt_i_2VD37DAZN48TRB8QRVCK?_encoding=UTF8&psc=1
No problem. Here is an example of a water powered backup sump. They're basically a standalone system that ties into the same drain as your electric sump, you just set the float to a higher level on your backup sump so that if the primary isn't working, the secondary will kick in as the water level continues to rise. I would also look into installing a check valve directly after each sump just as an extra level of security. Good luck!
If you have adequate city pressure you could do a water powered back up. I’ve been looking into one too.
Liberty Pumps SJ10 SumpJet Water Powered Back-Up Pump, Gray https://www.amazon.com/dp/B0013H94MO/ref=cm_sw_r_cp_api_glt_fabc_XE76RKJH4FA6W0V04T48
I have a backup Sump that runs on the city water. This way if my electric sump doesn't kick in this thing will. Its cheaper than a Battery backup and will last longer (assuming the city water keeps pumping.)
Fyi this is not the one I ended up with, I can't find the one I got. But this one is very highly rated. In any event, do your research for the one that's best for you. I actually hired a plumber to do the job through Amazon installation. It was.... ok.
Liberty Pumps SJ10 1-1/2-Inch Discharge SumpJet Water Powered Back-Up Pump https://www.amazon.com/dp/B0013H94MO
Used to work in the pump industry and as people mentioned, a gas generator is the way to go. The sump pumps with 12 backups aren't really any good. A generator does have a drawback though, they either have to be automatic or you have to be home to fire them up.
A great safety net is to get one of the water power backup ones and plum it in. No power needed in a pinch.
https://www.amazon.com/Liberty-Pumps-SJ10-Discharge-SumpJet/dp/B0013H94MO
https://plumbingonline.ca/products/liberty-pumps-sj10 https://www.amazon.ca/Liberty-Pumps-SJ10-Discharge-SumpJet/dp/B0013H94MO?th=1 looks cheapest on Amazon. Little more than a ups but this is never going dead.