The Solar Power Expert Blog

Sump Pump Battery Backup Systems

by Chris - June 7th, 2011.
Filed under: Projects. Tagged as: , , , , .

My wife thought a sump pump battery backup system was a comfort appliance. I agree with her, but thankfully we don’t live in a flood plane. If we did, I’d call it necessary.

Flooding is often associated with storms and high winds, all of which contribute to power outages. In extreme circumstances you need to focus on your family and the immediate situation – not whether your belongings will be safe in the basement. A good sump pump battery backup system will store enough power to keep your basement dry for several hours to several days until you can return to address the situation. These are also sometimes referred to as 12 volt sump pump hi & dry systems.

Complete Battery Backup Systems

Many people do not consider themselves to be technically savvy. If that describes you, then you would probably be most interested in a complete sump pump battery backup package. The Basement Watchdog system has been on the market for a while and has plenty of good customer reviews if you look around the net. Note: purchase of the system does not include a battery!

However, you can also find a few negative reviews too. The ones I read all had one thing in common: the pump not working when they needed it most. It is incredibly important to regularly (every 1 to 3 months) check your sump pump system to make sure it’s working. This is true weather it is a complete system like the Basement Watchdog or a DIY setup. Many people put these pump systems in place and then never think about them. That’s the ideal, but it’s never a good idea to rely on a neglected machine, no matter how simple.

DIY Sump Pump Battery Backup

One reason I’m an avid do-it-yourselfer is because I don’t mind maintaining machines that I build myself. If I made it, it doesn’t take me any time to fix it or maintain it. This particular project can also be made quite a bit cheaper as a DIY system and makes an excellent solar project.

The best electrical solar powered projects are ones that are used infrequently and have plenty of time to recharge. This describes a sump pump battery backup system perfectly. They need a large battery that is charged and maintained with a small trickle charge. Because the system uses standard 12v deep-cycle batteries, you can always hook the system up to a battery charger and generator in the event of an emergency lasting several days. The solar panel does not need to be capable of running the pump directly.

In putting my system together I started with the pump. I found this sump pump with a tethered float switch that pumps 30 gallons per minute and only uses 1/4 horsepower (186 Watts). The tethered float switch is easy to access for testing the pump. Plus, it can get all the way down to 1/8″ of water on the floor.

The pump is designed to work with 120V AC, which means the system could be plugged into the wall power or a generator without any need of a battery charger. However, since it runs on AC we’ll need an inverter like this 200W Power Inverter. It’s rated for surges of 500 watts and continuous output of 200 watts, which should just cover the 186 watts of our pump. Be sure this inverter will be mounted high and dry!

The system needs a big battery. Something that is capable of powering a pump for a long time. Why don’t we use a battery specially formulated for a sump pump battery backup system like this sump pump standby battery! This is the same battery used in the Basement Watchdog system. It’s a 12 volt, deep-cycle battery designed to for pumps similar to the one we’re using in power, and they carry it at a decent price! Of course, any deep-cycle battery above 45 AH would do. We have a page on solar power batteries at Costco and Wal-Mart.

These three subcomponents make a complete system. You can leave the 12 volt battery on a trickle charger and your basement is now protected from flooding, even if it happens during a power outage! That is comforting. Just be sure to test your system regularly!

But how do you make it a solar project do you ask? Simple, instead of a trickle charger that you plug in to the wall, get this 15 Watt solar panel trickle charger by Goal Zero. It has a decent price per watt for a ruggedized panel. Mount it in a sunny spot (or window) and it should keep your battery charged just fine.

Goal Zero Boulder 15 Solar Panel

Price: $159.99
Price per watt: $10.67
Silicon Type: Monocrystallin
Operating Voltage: 14
Warranty: 1 year
Comments: Goal Zero makes great products. This ruggedized, portable solar panel is no different. Multiple panels can be linked together to create more power output.

4 Responses to Sump Pump Battery Backup Systems

  1. Hey, I came across your info and had a question. I recently replaced an old sump pump with a new 1/2 HP. We lost power to Hurricane Irene, but luckily it happened well after the rain stopped and saturation was already pumped out… but for the future, I want to add a battery backup… I’m not very handy, but I’m hoping to get some info and maybe have my neighbor (very handy) help me out and I think he wants to install a backup also.

    I’ve read that my 1/2 HP needs about 2100 watts surge and 1100w running, so I am thinking a deep cycle marine battery + 2500watt (for example) inverter.. but how do I make it so that the battery only powers the sump if the main AC power goes out? This is where I am stuck.

  2. Paul,

    You’re right on the money with using a 2500 watt inverter for the pump. What you’ll want to do to complete the system is install a 1-amp or 0.5 amp trickle charger or a solar trickle charger on the battery to keep it topped off. Then add a float switch to turn on the pump when the water level gets high. Because buying the two together is so expensive, I’m a fan of pumps with integrated float switches.

    Good luck!

    Chris Troutner

  3. Chris, I need help in finding a solar powered battery system for my Gould 1/2 HP grinder/sump pump. It only works when we use the water (bathroom, laundry) in the basement – no water problems. It has worked on it’s own (very rarely over the years), after a lot of rain falls (several inches). Those few times were single pumps and out of the blue. Otherwise we have no problems. I am looking for an alternative to a gas generator due to the many power outages our area has been having lately. If you could recommend something already put together, or how to go about putting something together on my own, I would greatly appreciate it.

    Thank you,

  4. Hey K,

    Your situation is exactly the kind of thing I described in this article. Any of the product recommendations above should work for you. You said your maceration pump is 1/2 HP, which is equal to 373 watts. A 400W or 500W rated inverter should be able to handle your pump just fine.

    You can get the Basement Watchdog system for a complete system. However, if you know someone handy with electronics, they can just get a Group 27 or Group 31 deep cycle battery, a 0.5 amp trickle charger, and an inverter and you’re all set.

    Make sure you test the system thoroughly once you convert it to battery power. Don’t just assume it will work when you need it. 😉

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