Hi, I've just bought a used Chinese NB260 quad. It came with some electrical problems and the last owner has done a lot of messing with the wiring making it hard for me to see what is going on.

The problem is that the battery doesn't charge. I've replaced both battery and regulator but still have the same problem. I do think the original regulator was faulty as I reverse bias tested the diodes with my multimeter.

The new regulator passed the diode test. However, when turned off the battery voltage is 13.10. When I start the engine it DROPS to 11.7v. I have no electric devices running.

Could it be that the new regulator is connected the wrong way round? Would it make sense that voltage from the regulator would subtract from the original 13.1v from the battery rather than adding to it?

It is connected the same polarity as the old one. However, the old one seems to be broken (burned out due to being connected backward by previous owner possibly??).


If this is not the case, any suggestions on what could be causing the voltage to drop when I start the engine would be much appreciated.

Thanks for your input.

 

The battery is not charging. Since as you say the regulator is good then there is no power going INTO the regulator. Check the wires from the stator to the regulator which supply it with AC power.