Creative uses for spare SLA batteries

One of my UPS backup units had a circuitry failure, leaving me with (2) sealed lead acid 6V 12ah batteries like the ones pictured below:

All my other UPS units use a single 12V battery, so these can't be saved and used in those. My home alarm system uses a 12V SLA for backup, but the control panel case won't accommodate these either... no room.

From doing some reverse research, these batteries are often used in those emergency backup lights in commercial buildings and also in a Streamlight Litebox flashlight.. and that seems to be it.

Not sure what to do with them. I could try selling them but the used marketplaces have been pretty desserted with people having less disposable income this year. Also doubt there's much demand for these on craigslist.

Don't want to throw them away since they have quite a bit of life left.

Anyone have any ideas how I could repurpose these?
Jupiter, Florida
I always keep one of them around with a 12v cigarette lighter (female) outlet soldered on to the terminals. It's a great way to test things that plug into a cig lighter outlet. Such as configuring a dash-cam. You can also use a USB car charger to charge your phone this way.
Pittsburgh,PA U.S.A.
If you can't find a use for them, stop by any remote control model airplane field and someone there will want them. Two of them can be used as a 12 Volt battery to run the field charger for electric powered remote control model airplanes, or to power the hand held starter motor for gas powered remote control model airplanes.
I had a Schumacher jumper pack 20 years ago which had a 12 amp hour battery inside of it, the UB12120, though it had more significant terminals for passing 50+ amps to assist a depleted engine starting battery.

Two 6v batteries is a 12v battery, in two pieces.

If you do find a use for it, how will you recharge it/them?

Ideally such AGM batteries in deep cycle use need to be brought to 14.5 to 14.9v with upto that 3.6 amp maximum amperage available that they list on teh sides. Hold at 14.5. to 14.9v until amps taper to 0.06 amps, or until amps stop tapering at constant voltage, and start rising.

If held too long at 14.5v they begin to overcharge and will heat up. thermal runaway is a possibility especially with an older battery.

If one only brings and holds them at 13.8v, if they are new they will reach true full charge eventually, but when older they will not.

Most chargers designed to charge these small AGMS are just single voltage wall warts, usually 13.6 to 13.8v, usually less than one amp maximum output and well less than one amp when the terminal voltage is above 13.2v.

Its adequate for an Ok lifespan in very rare deep cycle duty, very inadequate for long life in regular deep cycle usage.

My neighbors have toy cars for their kids which take small 12v AGM batteries, and their chargers take forever, as they are just 1 amp and 13.8v single voltage. The kids learned to take me the dead battery when they want to use them soon. I greatly exceed their 'recommended maximum charge rate' until battery gets to about 105f, then back off target voltage and thus amperage.
Usually by this time there is more than enough juice for them to play with the cars until bored.

I've taken the batteries overnight for a true full charge. That final 20% of charge on such abused batteries usually takes about 10 hours, but I can get them to 80% charged in less than an hour.

These small asian made AGMS can be remarkably tolerant of abuse, and can last a respectable lifespan when they are recharged promptly and fully by a charger capable of doing so. I do not classify a single voltage wall wart in that category.

What one can do with such a battery is buy a 12v computer fan stuck in a parked car's open window to help keep interior cooler when parked.

the Noctua NF-f12 moves 53 cubic feet per minute and draws 0.05 amps @12vDC.
every 20 hours it will consume 1 amp hour from the battery.

Your batteries wired in series store, when new and fully charged, 12 amp hours of capacity.
Western S.C.
Various versions of those things are used for numerous applications, from wheelchairs to gates. I'm using a 12-volt, 35 ah one in my Prius. It's still functioning ok after 5½ years, cost a lot less than replacement 12-volts the dealers sell, and (after minor modification) is just as safe.
Katy, Republic of Texas
I have 8 of these from work:
2020-10-19 14.44.09.jpg
2020-10-19 14.46.27.jpg
2020-10-19 14.45.40.jpg

These were from medical equipment that has the batteries replaced based on time, so they are just fine. These 4 have been sitting on the floor in a box for a year and still are charged. The other 4 were just removed a month ago and are sitting @ 12.95v.
I had put 2 of them in older UPS units that needed new batteries. These were bigger than what came out, so I had to modify them a little to fit:
2020-10-19 14.33.55.jpg

I still have 6 left, one will be used for another UPS, the others, I am thinking of making a battery backup for my CPAP that has an option to run off 12v.


Staff member
New Jersey
2 x 6v batteries in series will act exactly like a single 12v. I’d run them in an alarm or other backup where the battery isn’t quite as integrated.