My son and I are designing a 3D printed body for his pinewood derby car.
We want to add some colored LED lights. I found some lights that I think will work well, from a mechanical fit and looks perspective. I need a battery that will power the lights for about 3 hours.
Weight is a concern, but shouldn't be a problem. The car can only weigh 5oz maximum. Tungsten weights are typically added because you want the car as close to 5oz without going over. Ideally the weight is compact and distributed properly. So I can possibly use the battery as weight, but I'd like to keep it as light as possible because I can use tungsten strategically to distribute the weight better.
The LEDs I'm looking at have a forward voltage of 3.0-3.6v and a current of 20mA.
I need to have 6 of them. So if I'm not mistaken (and I might be) I would need 360mAh of battery (20mA x 6LED x 3hours = 360mAh). It appears I could use a coin type battery for this. I see some coin batteries at 1000mAh capacity for 3.6v.
Does this seem like a possible solution? I'm assuming I could wire the LEDs parallel to the battery and would not need any resistors at 3.6v.
I'm open to any ideas and considering a rechargeable battery. If there is an off the shelf charging PCB (I can make an inline charger unit or integrate a small PCB into the body.)
Not asking for battery weight analysis, etc. We are in preliminary design and just want to figure out what is practical/possible.