My project is a very simple 12V emergency lighting system. The deep cycle battery is 12V 18Ah SLA, (charged by a Pulse Tech Battery Maintenance System 100X010.) Lights are LED strip (5m, 3528 - 300 lights). Wire is 18AWG lamp wire. Inline 1A fuses, and a SPST switch for each circuit, (one for kitchen and one for livingroom.) The schematic is attached. (I hope.) Neither circuit is longer than 20 ft. from the battery. Livingroom draws 583mA, kitchen 594mA. My first (only) test was 27 hours with both circuits on. (SWEET!) Not sure how close to battery depletion I was, but it did take almost half a day to recharge to full.

Battery is enclosed in a plastic Group Size 24 Battery Box (larger than necessary, but also encloses the fuses, stores my charger, and I drilled holes into the front for the switches), and the lights are stuck inside a length of vinyl "J" channel, providing a nice sort-of-indirect lighting effect along the top of my walls. (Tried unsuccessfully to take a good pic of it. Maybe I'll see if my son can GIMP them to looking better.)

Pretty cheap, pretty effective, though I may want more light in my livingroom eventually.

I have a question about a LED driver circuit. Though I don't seem to need one for it to work, would such a circuit benefit me as far as battery or LED life is concerned? If not, maybe i'll move this to 'Finished Projects'.

Thanks in advance.

 

You wouldn't be able to use a driver without using different strips. These are apparently designed to work when directly connected to 12V. The purpose of a driver is to supply the proper current to LEDs when the power supply is not already matched to them. For instance if you wanted to use a 6V battery with your system, you would need some driver circuitry to make that happen.

Your strips may simply use current limiting resistors internally. That is an efficiency loss that might be avoided with a fancier, constant current driver design. But I doubt it would be worth re-engineering those strips.

 

Thank you for the super quick response, wayneh. I was hoping that was the case. And, yes, there is in fact, (upon closer inspection) a resistor for every 3 LEDs on this strip.

It's just an overgrown flashlight, but my wife & I love it. It was just a project that I wanted to do, and we are using it from dusk to bed-time to see if we can save some $ on electricity. If I can get some pics that accurately show the light levels in these two rooms, I'll post.

Thanks again.