Author Options:

12 2.4V lights in parallel, how do I wire it to a wall wart? Answered

I have twelve 2.4V flashlight bulbs in some lovely ceramic fixtures that I have wired in parallel with quite a bit of 26 gauge solid wire (6" between each bulb and about 7' to the power supply). Despite them wanting 2.4Vs, 3Vs supplied with 2C batteries makes them only dim. I want to hook them up to a wall wart but I have had no success. 5V and 3V wall warts do nothing.

I tried two others that worked for a while then burned out:

AC Adapter
INPUT: 120V ~ 60Hz 11w
OUTPUT: 7.5VDC ===900mA
MODEL: SCP48-75099

AC Adapter
INPUT: 120V AC 60Hz 15w

I just got rejected from a juried show because it died as the jurors were looking at it.


ditto with everyone else - your current requirements are much higher than the supplies you are using.

the reason things are so dim is the voltage is "sagging" with your batteries / supplies not able to handle the current load.

I would wire 6 strings of 2 in series wired in parallel.

this would give it a voltage requirement of 4.8v (close enough to 5v).

you can pickup a "5v 4amp" (I would search for that exact phrase) power supply on ebay for about $10.

assuming the bulbs are 1 watt each - that should handle it.

alternately - a computer power supply (check google for how to jumper the "enable" wires) has a 5v output that could handle about 10x what you need.

Parallel is your problem.
Run the lot in series and you want ~30V. Or 4 strings of 3x at 7.5V, 3 strings of 4x at 9V (better). But I think you'd need a heavier supply, such as a computer PSU supplying 12V to 2 strings of 5x plus one string of 2x off the 5V output.


Those lights all together may well draw 3-4 amps. You need to find the power rating of the lamps and get a transformer rated atleast that high.

Agreed. Boosting the voltage and running them in series might alleviate the amperage draw issue, but if the transformer can only supply a few watts you're in trouble.

Say they're 1w bulbs - that's 2.4v 410mA
To run them all in parallel you need 2.4v @ 5 amps


7 years ago

Another possibility would be to break them up into groups of maybe 4 lights each and power each group separately.