Can I run different voltage LEDs off a 9V battery? Answered
I have a small project that uses a 3 light LED list that runs off of 3 AAA (4.5V) batteries, but I also want to power a 12V LED string (for cars about 24" long) and I am uncertain the mA draw for either. This is for a follow-up to fine tune my son's 2014 Halloween costume.
I run the 12V string off of 10 LR-44 batteries and get about 3 hours use out of these, so I know the mAh draw is relatively small. I'd like to extend the use of the 24" string. The 3 LED light goes for days on the AAA's.
Because both lights are used for the same application, I wanted to see if I could join them together in a single power source and power off of 1-9V or 2-9V (in serial for a total of 18V) batteries. I think my preference would be the 18V with an in-line resistor, but I do not know which resistor to use.
Is this the correct approach?
What are other alternatives?