Electrical issues: voltage drops when electric motors turn on
 

I'm having electrical issues, specifically with voltage dropping significantly (<10V, sometimes even lower) whenever any accessories with electric motors turn on (hatch or bolster motors, fridge). It's pretty annoying, whenever anyone hits the bolster buttons the radio and GPS shuts off :rolleyes:

I had the batteries load tested and the guy said 3 of the 4 were fine (2 banks of 2), so we took the bad one out. The voltage doesn't drop at the batteries, just at the dash. Could it be a corroded wire or connection somewhere?

How do you troubleshoot this stuff? I'm proficient with a multimeter.

Check all of your grounding points. If corroded will cause a drop. Also the wire from batteries/engine is possibly too small. I ran a bigger wire up to dash area and added a power tap to power the high draw items. Also use the multimeter at the volt gauge. I think you will find the drop is not as large as the gauge shows.

Another thing to check is your kill switch wiring size. I worked on a boat once that had the drop at dash and it was because of the thin wires of the kill switch.

I am amazed at the wiring in boats. They usually use a #12 from the engine harness to run everything off the dash, bilge blower-bilge pump-lights-hatch-gauges-radio....

I did the same, ran #8 straight from battery to run everything except gauges and ignition which is all the harness should do. I think I had 1v drop at dash with nothing running.

I'm also amazed with boat wiring, I had all sort of glitches until I broke out the solder and went to town for a few hours, I also ran a larger gauge wire as noted above.

I don't know how anyone can think clips and crimp connectors are worth a $hit, and if you use crimp connectors or wire end to a sensor, at least they could have done was use a proper crimp tool...which they usually don't...

Soldering has solved all of my problems, but did take me a long time. Oh yeah and use shrink wrap, GOOD wrap too...electrical tape is only a good solution in a bind...

Thinks got better for me immediately after I soldered in the ground wires to the fuse panel...