hi fellas this is my first post i am wishing to build an IR Illuminator for ghost hunting i want to make it from 3 5w high power ir led and wire it in a parallel led array so each led gets same power i worked out if i run them of a 3.7 volt battery i would need to add a 2.7 ohm resistor to each led so not to over power the led thing is i am only getting around one and half hours continuous use so what would i need to do to run same set up of two 3.7 battery's any help please fellas ?
Sounds like you know what you are doing... you scared me when you said parallel LEDs, but you are actually using a resistor on each one. Thanks! That gets missed by a LOT of people.
As far as running with two batteries, simply connect the two batteries in parallel and your light should last twice as long!
*Special Note : When you connect two unbalanced batteries in Parallel, you run the risk of causing current to flow between batteries. Never connect a fully charged battery in parallel with a used battery!
The battery with the higher voltage will actually cause current to flow backwards through the battery with a lower voltage. So either connect them when they are both freshly charged, or when they are dead. You can always use a multi-meter to confirm the voltage is the same prior to connecting them.
