Anything special about a battery for a 12V sump backup?

[sixdogs]

I'm putting in a 12V backup sump pump and there is zero mention of the battery in the manual. Seems that the biggest I could find would be the one to get. I figured to get a huge AGM battery and call it good. Then I got to thinking that there are Red Top and Yellow Top Optimas that would take a discharge better and other types of batteries as well.
Anyone know anything about this?

 

[Looking4new]

First hand knowledge I have none of, but I would think that a deep cycle battery would be what you are looking for.

 

[KYErik]

I have a 12v backup sump pump on top of my 120 volt AC sump pump in my basement. I use a regular car battery in a plastic box with integrated battery tender. The first battery lasted about 9 years before developing an internal short (which caused the charger to flutter back and forth between charging and full about 3 times per second).

If you have lots of power outages (you expect it to draw on the battery a fair amount) or a finished basement (with lots to lose if it floods), then a large deep cycle would probably be best. My battery got a workout when my ac sump pump locked up about 3 years ago. I just had to replace the battery this year.

 

[Deere Dude]

Get a good deep cycle battery.

 

[dickfoster]

I'm putting in a 12V backup sump pump and there is zero mention of the battery in the manual. Seems that the biggest I could find would be the one to get. I figured to get a huge AGM battery and call it good. Then I got to thinking that there are Red Top and Yellow Top Optimas that would take a discharge better and other types of batteries as well.
Anyone know anything about this?

Yeah get a good deep cycle type since it will be discharged a lot. Forget all that Optima color coding nonsense and get a US made Odyssey if you're gonna spring for an AGM. They are all duty, all purpose batteries including deep cycle and starting which I think Optima says are their blue tops or otherwise a marine battery for deep cycle.

 

[buickanddeere]

As previously stated, deep cycle. Nobody has ever installed too large of a backup or too large of a starting battery either .
Does the home have a transfer switch to connect a generator and run the 120V sump pump before the 12V backup system runs down?

 

[sixdogs]

OK, deep cycle marine battery it will be. Yes, I have a generator and a partial gravity drain but want to be sure I can handle the five minutes after a power outage if we are getting more water than the drain can handle. In five minutes I can hook up the generator.

The power rarely goes out and I figure if I install this it will never go out and if I don't install it, it will be out all the time. Just insurance.

 

[RNeumann]

Depending on the setup the pump "system" may or may not charge the backup. Some systems, like the UPS on a computer, charge the battery while others do not. With a proper AUTOMATIC charger you can maintain a battery in this situation for years. The thing will hardly ever see anything other than full charge and won't get moved or bumped. If you have "x" money to spend on batteries don't spend it on battery technology that isn't needed. I'll take twice the amp hours of conventional lead acids over half the amp hours of an AGM. Go down to your basement every few months, look at the pump and inspect the battery fluid and connections. Everything should be good for years.

I'd sleep better knowing I had a week of battery backup than high priced technology that only lasted 3-4 days.

And as stated by others you want deep cycle.

 

[dmccarty]

I have been reading up on batteries for boats. Not start batteries but the type and capacity of batteries one needs to live on a boat where your power is stored in batteries and one might have 1,000-2,000 Amp Hours of 12 volt batteries. Reading what electricians that deal with these batteries have to say, there are many companies selling deep cycle batteries but few companies that make them. There is no regulation on batteries and companies will just slap a label on a battery that says it is marine deep cycle when in fact it is not.

Lead acid batteries have a limited lifetime which is reduced when a decent amount of power is taken from the battery. The battery lifetime, i.e., number of cycles the battery can go through, is also reduced if the battery is not fully charged before it is cycled down again. For instance, using 50% or more of the power stored in the battery will greatly reduce the life of the battery compared to only using 30% of the power in the battery. As power is drawn out of the battery, voltage decreases and around 50ish% of the battery capacity it the voltage might be under 12 volts.

Rolls is one of the well respected battery OEMs and here is the spec sheet on a small 85 AH battery.

http://www.rollsbattery.com/wp-content/uploads/batteries/12FS85.pdf



If the battery is only drawn down 10%, it has a lifetime of about 1,800ish cycles. If 30% of the power is used the number of cycles is about 1,300ish. But using 50% of the battery's energy drops the the lifetime of the battery to 1,000 cycles. If 90% of the energy in the battery is used, the number of cycles is about 300-400.

For a sump pump battery that is only used during a power outage this might be a who cares.

With the above in mind, check how many Amp Hours the pump will use and figure/guess how long the pump will run. Then buy a battery that has at least double the number of Amp Hours if price permits. More Amp Hours is better if the money makes sense.

It is also critical the battery is fully charged before the next draw down cycle and the battery should be charged correctly.

I would just use an AGM battery so one would not have to worry about the battery's water level.

If flooding was a real risk when the power was out, one could buy batteries with larger Amp Hour capacity and/or connected them together to produce much larger capacity.

Later,
Dan

 

[PILOON]

Regardless of battery U install I'd suggest U install an intelligent 1-2 amp charger, that way U will be assured maximum performance when needed.
Said charger will also lengthen the life of your battery.