Powering a strip LED 13v 240ma with 2 9volts how to question:

I apologize in advance if I posted in the wrong place as I am new here.

I have a 12 series LED light that requires 13v at 240ma and would like to power it with 2 9v batteries.

What would be the best configuration to make this work? I was thinking of putting the batteries in a series and using whatever to drop the voltage and amperes to provide a longer life for the light.

Sorry if this is a stupid question for you genuises out there!

Thanks,

Two 9V batteries will run your LEDs for less than 1.6 hours. If you really want to be replacing batteries that often, connect them in series, and connect a 20Ω 2W resistor between the +18V and the positive input to the LED strip.

How about 4 9v?

I am working with limited space but can accommodate 4 9volts in a series.

If I can pull a burn time of 3 hours per session before needing to replace the batteries, I would be fine with that.

Thank you very much for the help!

jscott70 said:

I am working with limited space but can accommodate 4 9volts in a series.

If I can pull a burn time of 3 hours per session before needing to replace the batteries, I would be fine with that.

Thank you very much for the help!

Click to expand...

Make two sets of two-in-series. (+- +-)
Connect the two strings in parallel (+ to + and - to -)
use the 20Ω resistor as described before.

Use 10 AAA cells.

The voltage will be 15V when new and 10V when old, the lights should be able to work from both extremes of voltage.

10 AAA's

According to the Mfr. of the light anything under 13 requires a heatsink. Am trying to avoid a complicated system but if there is a better power source option, I am game.

Thanks,