COB LED Battery power illumination drop off

PROBLEM:

24 SMD COB LED has too much illumination drop off over 3 hours. Currently powered by four 3V button batteries.

PREFERRED SOLUTION:

Get this battery powered LED to perform more consistently over a few hours.

THE STORY:

I’m working on a little project at home for a custom show car I built. I’m trying to get my interior lights to work independently with a small power source.

I have a few COB LED’s placed inside the car and can not run wiring without destroying my interior.

I thought I designed a perfect fix using four 3volt button batteries ran in series. The small batteries allow me to hide the power source without running more permanent wiring. It only needs to last a couple hours for the final judging.

Currently, they are lasting much longer then needed but the drop off is very dramatic. From over 100 LUX when first switched on, to 30 LUX after 10 minutes, 17 after 20 minutes, 15 after 30 minutes, then it starts to stabilize and remain around 13 LUX with very little drop off.

These lights do not need to be over 30 LUX. They are only decorative lights but the drop off can’t be so drastic that a judge can notice the difference over a 20 minute period.

QUESTION:

What are my options to get a more stable output with much less drop off in ilumination?

Easiest would be to change to a battery with a higher current capacity; AA would be best but even AAA should last much longer. CR2032 really aren’t designed for supplying much current over time. What current do the LEDs draw?

Running off the car’s battery would make them last much longer but make sure you don’t drain the battery far enough to make starting difficult.

/mike