I want to make some lights with these strips. The working voltage is 12VDC but no where can I find what the voltage variance is. The goal is to power them with 18650 Li-ion cells in series, but 4 is too many and 3 not enough to keep 12 volts. I am not to worried about amp issues because I will only be using a small section of the strip. Anyone have any information that will help? I have searched but everyone is powering with the standard, heavy lead/acid batteries.