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12V LED to Battery Power? Answered


I'm just getting my own cab company started in my medium sized town, and to begin I'll be using my personal vehicle - thus, I'm using items I can remove so I don't get harrassed on my days off, such as magnetic decals and a magnetic top light.

My question is this: Is there a way to convert a 12V, 96 LED light over to battery power? The toppers use a direct cable to a car charger port, but I hate having that cord just hanging out in my cab. It is tacky and unprofessional - at the same time, I very much do not want to punch holes in the top of my car and wire it to my dome light.

I have found several rechargeable, compact 12V batteries online, but I've no idea how I'd hook them up. I'm smart enough to know that I can't just wire it directly to the device - the battery would last minutes at most. I think I'd need some kind of transformer, perhaps?

Any suggestions?

And here's the battery I would use:

Voltage: 12
Lead Acid Type: General Purpose
Capacity: .8AH
Chemistry: Lead Acid
Lead Acid Design: AGM
Product Category: Sealed Lead Acid
Terminal Type: WL, Wire Leads
Weight: 0.8 lbs
Length: 3.78 in
Width: 0.98 in
Height: 2.4 in


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3 years ago

Assuming the LED's are not too power hungry and work with 20mA you still need between 1 - 2A to power them.
In theory your 8AH battery should work for around 3-8 hours with the LED's.
Problem is that you do not want to deeply discharge it, so you should add a battery shut off relay that you can set to 10.5V or so.
Connecting is straight forward:
From battery positive onto a fuse with 3A, from the fuse to a switch or directly to positive (red) on the LED strip.
Negative from the LED strip (black) goes back onto the negative terminal of the battery and then there shall be light.


Reply 3 years ago

Thanks for the reply!
The only things I'm having trouble following is attaching the fuse.

Do you know of any instructables that follow a similar premise? Or, a link to the device in particular? I'm sure I could extrapolate how to do it if it's simple as you say.

And is there a way to extend that life to 10-12 hours, such as installing a second battery?


Reply 3 years ago

Well, the fuse goes simply between positive of the battery and the connection to the positive of the LED.