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Where to find a small form factor 12v Battery?

I am looking to build an LED light that can be powered directly by a 12v source or use an internal battery. I expect that the fixture form factor will be about 4" in length by 2" to 2.5" in width and no more than 3/4" in depth. Internally, it needs to fit two LED units (each draws 0.1-0.2amps and only one would be on at a time) that are 1"x1"x5/8" each, the inside component of a single pole double throw waterproof switch and the remaining space for batteries. I would like to fit the maximum amount of available capacity as possible in as small a space as possible. I am looking for battery suggestions - small form factor, 12v, preferably available via a regular source (i.e. don't have to be special ordered from China), low self-discharge rate, ability to withstand temperature extremes (specifically 120F-140F degree heat). I'll consider wiring up batteries in parallel and serial to get the charge depth and the proper voltage. Any thoughts? I looked at A23 12v batteries and 2CR-1/3N 6v batteries (wire in serial) but I'd like to find something with more available capacity. Also, I'd prefer a non-toxic battery, but will consider lithium, and the ability to be recharged would be a big bonus. I'm guessing there's nothing out there that would give me enough life to be happy, but I thought I'd ask.

Thanks!

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StojanK17 months ago

Very nice idea. I already made plans to improve it a little bit, with rechargeable batteries. Will let you know when I finish it :)

chemy6 years ago
Look at the following website that has many cells.
battery
TSC6 years ago
Here look at this!
kricketone6 years ago
I have 30 of these great 12 volt batterys NP2-12 2.0 AH google these.
cid23236 years ago
computer backup batteries, motorcycle, jet ski, quads, kids electric riding toys, riding lawn mowers. all use 12v DC batteries....the amps will vary...
Most better electronic stores have varying size batteries. Also check some of the online places like jameco or etc. I bought an 8 cell battery holder from frys.
airsofter16 years ago
Amazon, Ebay... Just google it and you'll be on your way.
awz1236 years ago
Ebay...
Johenix6 years ago
My coice: 8 AA cells in series, in a plastic holder, 1.25" (3 cm) square, 4.5" (11.5 cm) long with 9v connector snaps. It would fit in a small grated parmasan or romano cheese container.
Second choice: 8 AA cells in series, in plastic holder, 1.25" (3 cm) x 2.5" (6.5 cm) x 2.5" (6 cm) with 9v snaps.
Dr.Bill6 years ago
Look into wheelchair Gell Cells.
Butt loads of capacity.
Beats the Energizer Rabbittttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt .............................
account3r26 years ago
23a are really small and a23 are kinda small...
janw6 years ago
use one of these types:

V23GA, 23A, GP23A, MN21, L1028, A23, LRV08, AG23, R23A, VR22, V23A, K23A, E23A

dimentions: 28mm long, diameter 10,4mm
75437199-batterij-accu-type-a23-mn21-lr23a-gp23-v23ga.jpg
seandogue janw6 years ago
Impressive. I was about to suggest that he stack hearing aid batteries. I presume that these are made the same way, although "pre-wrapped"...very nice.
Why don't you use a Lithium halide battery..
nevdull6 years ago
Using a Maxim 734 you can get 120mA @ 12V from a 4.75V supply.
nevdull nevdull6 years ago
abadfart6 years ago
what about a motorcycle battery
thepaul936 years ago
Two nine volt batteries connected in series, then connected to a 12 v regulator.
Closer6 years ago
Very small 12 volt batteries are used in some Remote Car Starters. I have seen them at some dollar stores but most car dealers or Remote Car Starter installers will have them available or know where to get them. Also, some 9v batteries are comprised of 6 little 1.5 v batteries (AAAA size?) If you took two apart, you would have enough to make quiet a strong 12 v source.
junits156 years ago
12v camera battery :P
warengadia6 years ago
i use a 4, 3v lithium battery for my motor fan
jeff-o6 years ago
So, these are LED modules (I assume) originally designed for use in a car? Chances are, they'll have a built-in current limiting resistor that allows you to connect the module directly to the car's electrical system. It's also horribly inefficient. Are you able to open these lights and swap out the resistor? If so, then you can choose a value that will allow you to use the lights with, say, three AA batteries.
kcls (author)  jeff-o6 years ago
Thanks Jeff. The modules are actually designed primarily for replacing G4 halogens on boats. They accept from 10-32vDC. I'd prefer not to modify the units at all. I've done a lot of research on a lot of different modules and have settled on these due to their brightness, warmness and diffusion. At 0.2A per hour I would need 4.8AH of capacity at 12v to have the light stay on for 24 hours. 24 hours is the minimum amount of time I would consider. So... small form factor and 4.8AH just doesn't seem realistic.
jeff-o kcls6 years ago
Hmmm. Well, I use an 11.1V, 7200mAh lithium battery for my bike lights. The battery is the size of a water bottle. Would that be small enough? I got it at batteryspace.com.
Allowing for some losses, 2.8ah aa x 6 might fit. I'd look haresistd to find the limiting resistors if they're fitted, because they are bound to waste energy. A boost,current controlled psu is buildable, if you want to try it, but I'm guessing these things are really ~8v
If you had a switching PSU, you could use a lower voltage battery and boost it to the LEDs, saving a lot of space, like 4 AA NiMh batteries
kcls (author)  steveastrouk6 years ago
Any ideas where to find a tiny PSU that will boost to 12v from 6v?
Taost kcls6 years ago
Ever heard of a joule thief device?
Energycraft6 years ago
Thanks
rickharris6 years ago
Smal form lead acid batteries are made for the alarm industry. Other than that your going to be making up a pack of cells of you chosen size.