1 pump for slurry pump

Simplest path to replacing a sump pump battery with LiFePO4.

Dave K. asked:

I have a sump pump with dual pumps. The main one runs directly from mains power (though a controller). A second one, connected to lead acid batteries runs directly from the batteries if the water level rises above a certain level exceeding the normal level. It's about time to replace the lead-acid batteries (5 years). These batteries are charged with a trickle charger as their use is very intermittent. This trickle charger puts out 13.5V, which I know is less than the ideal voltage for LiFePo4. I also realize this will not fully charge a LiFeP04 battery, but to change it requires opening the controller and making hardware changes. Since a single LiFePO4 battery would give me the same capacity as 2 lead-acid at lower cost. I'm looking for the best solution. My question: Is this safe (I think so) and an improvement on my current setup?

time2roll replied:

13.5 continuous will actually get the LFP up over 95% given enough time. I would connect as is and give it a test after a few weeks.

Dave K. followed up:

Thanks, that was my assumption, but wanted to confirm before going ahead. May get a small LFP charger just so I can top off the battery to make sure it's balanced.

French_guy shared:

I’m somehow in the same situation. I have 2 sump pumps: One is an AC pump (primary) and the second one is the backup pump, which is a 12V DC pump. The 12V DC pump was powered by 2 x 38Ah Yuasa AGM battery in parallel. So I installed a LiFePO4 12V/100Ah battery (Redodo). The battery is feeding the Wayne controller through a mini DC 25A breaker. I’m looking to install a maintainer that would keep the battery at ~13.2V. My plan would also be to use the backup pump to “exercise” the battery once in a while. I’m also looking to replace the Wayne controller that activate the pump with a float switch and a timer.

JLV03 added:

If the Wayne system still works, I don't know if I would mess with it. I burned up a Basement Watchdog controller when it kicked in and ran the battery empty. That's a bit of the beauty of these LiFePo4 battery replacements - typically they have a BMS that is not going to let the voltage go all the way down. They'll hit the bottom and shut off, not try to keep things going past the point of no return.

davros mentioned:

I am looking for a solution myself -I see Vevor have a couple of product, has anyone looked at them?

French_guy responded:

Following....I wonder how good such units are at charging and maintaining LiFePO4 batteries