Get one of the boat pumps that looks like a bicycle pump, and attach a hose that will reach outside from the lowest area of the basement (where water would gather in the event power fails and the sump pump doesn’t work).
I use a shop vacuum, but it requires electricity.
I ended up going with the marine battery option as well as a secondary sump pump (in case one of them failed). I never had aa problem with that basement flooding again.
I had this setup but with one marine battery and a trickle charger. The only difference is I had a DC pump so didn't need the inverter, just a transformer for the AC.
It worked great.
Lots of battery backup sump pump systems at Home Depot. Most of them include a new pump. I don’t know how powerful your current one is. You could get a complete 1/2 HP system for under $500 easily.
https://www.homedepot.com/b/Plumbing-Water-Pumps-Sump-Pump-Backup-Batteries/N-5yc1vZbqp7
I put in a battery powered backup sump pump that also issues an alert if triggered. Commercially available and good insurance.
My backup sump pump is water powered. It connects to the house water line. It uses about 1 gallon of water to pump 2 gallons from the crock. No backup battery to worry about with long power outages.
If you have city water and not a pump you could look into Water Powered Backup Sump Pump.
The battery backup plan is good, but you need to think about if you are away for an extended period and the batteries go dead. Maybe there’s a low probability of this happening, but it isn’t zero.
Could you have spare batteries on a trickle charger and on an A/B switch, then train a friendly neighbor to throw the switch?
We just put in a whole-house generator with an automatic transfer switch and some load shed modules. We don’t have a basement, so the flooding problem doesn’t exist. But I don’t want the house to freeze up if we are away for a few weeks in the winter. I also don’t want everything going dark and cold when we have family in for the Thanksgiving to Christmas period. It was expensive, but our area gets extended outages (7 - 10 days) every few years, always in the winter. I expect those will stop now that we’ve invested in the backup system!
Get a few marine/truck batteries, a charger, and a DC sump pump. Install the pump so it’s float is a little higher than your AC pump’s float. It will only come on if the A.C. fails.
A 12V backup system is worthwhile in case of pump failure though the battery won’t last long nor will the pump be high volume in case of big rain.
A smallish generator will keep your 120V pump system running for quite a while and you can rotate the power to other systems like fridge, TV’s or window A/C units if the rains let up.
Don’t run it indoors!
Pretty simple, not expensive. Don't know how long it lasts.
Why go AC/DC? This isn’t an Ivy League swimming pool. Just hook a car battery up to a nice 500gph bilge pump on a float switch (RULE makes a very reliable assortment - be sure to buy the separate float switch, not the integrated every-three-minutes kind,) and you’re good to go. Keep that battery charged with a little maintainer/trickle charger. The whole setup can sit right on a two-by-four, weighed down by the battery. As Kenny Bunk would say, Bob’s your uncle, Fanny’s your aunt.
Check the water pump options at Lehman’s: https://www.lehmans.com/category/shallow-well-pumps
Or off-grid electric well pumps at places like https://www.rpssolarpumps.com/
I’m sure one of them will have something that suits your situation.
My house sits at the bottom of a hill and I think it’s on a spring as well so my pumps are very active. I had my plumber install pumps with the AC charged battery back ups. I learned my lesson when we had a real nasty storm that knocked out the power for about twelve hours. We bailed just short of 500 gallons of water out of our two pits in that time frame. We kept track of the number of 5 gallon buckets that we dumped in the shower drain. That was a Friday night and the pumps were installed the following Tuesday.
That was the night that Offutt AFB got hit by a tornado that did about $30 million in damage to two of the E-4 planes that are based there. The base is about 13 miles straight east of my house. My neighbors and I were standing outside having a beer and saw this nasty looking greenish black cloud come blowing fast over the neighborhood and it was rotating fast. My neighbor said “looks like Bellevue (where Offutt is located) is going to get hit”. And it sure enough did.
Our power goes out frequently. We run it 24 hours a day when the power goes out. It typically stays out for a couple days. We have been using a 5kw generator from Costco for nearly 30 years. We have natural gas for heat, hot water, and our stove so it runs the whole house with almost no compromises. We also run the generator on natural gas. We paid $400 for it. There are still 5kw generators available for around $400. I doubt that they will last as long as ours has but you do not have to spend a fortune. A sump pump would be no problem at all for a 5kw generator.
Get a DC pump with a battery backup. Set he level of the DC pump such, hat it will start to kick in when the other one fails. At the same time provide a continuous trickle charge to the backup batterie(s) Just a thought.
Ecoflow Delta
Not sure your situation, but ideally you should be trying to stop the water from getting near the basement in the first place.
I had a corn field up hill of our house and it sucked up the rain water, the water seeped into the ground and then it hit an impervious underground layer that sent an underground river straight to my house.
We got out the backhoe and dug a trench until we hit water, then laid field tile and backfilled with gravel. I ended up sending all that water around the property.
The pipe just about never stopped flowing with water coming out the end. But my sump pump did not run again except only during really heavy downpours but that was still barely.
Obviously you may have a completely different situation but if you can interrupt the water before it gets to your house, that is the best thing to do.
I have had a Generac generator for over 10 years. I just have a ranch style house and bought a small single cylinder engine generator. It uses 1/2 the propane of the next bigger unit with a twin cylinder. That’s why I bought this model.
I can run it for TWICE the length of time as a twin or spend half the money.
It does everything we need it to do. We miss nothing we care about while on the generator. (We can do without the 230 volt air conditioner and the 230 volt dryer during the outage.)
Best $3500 bucks I ever spent. Installed it myself.
I don’t even have a sump pit. Dry unfinished basement.
Battery backups result in bad batteries in 2-3 years, even with zero usage. And they are only good for a limited time. This is your only sure-fire option, if you are on city water.
https://www.watercommander.com/articles/water-powered-backup-sump-pump-ultimate-guide