That darn 12v cable...

donn0128 wrote:
Even though the inverter may be rated for 200 watts, or about 18 amps, the cable is probably not large enough to support the load. In simple terms you are probably strangling the inverter.

I agree.

I had similar problem. I have a television rated for between 12 and 14 volts input. I decided to wire it in to the nearest 12 volt line It would work until something like the water pump came on.

I ended up installing a golf cart solenoid directly to the battery and the TV so that I could switch it off. I used the smaller 12 volt circuit as the signal power to the switch connected to the solenoid so that when the main 12 volt power was off so was the solenoid even if the switch was on. This provided direct 12 volt on a heavier cable to the solenoid and then I used 12 gauge cable to the TV. No more problems. I also connected a converter on a short cable to the solenoid so that I could connect the VCR/DVD player as well. The player runs on 110 through the converter and is switched at the solenoid as well. This prevents voltage drop to the converter as well.

Direct current (DC) systems are much more sensitive of cable runs and voltage drop through those runs than is Alternating Current (AC). That is one reason they are not practical for commercial power and why AC came out over DC



Just to give you another example.
I was having trouble with the towing lights on my pickup not glowing very brightly. LED bulbs did not work properly at all.

I tested the voltage at the light socket and found I had just over 9.5 volts with the engine off and just a little over ten with the RV engine on.

It was the run. The trailer light plug was wired in to the tail light harness on the RV. there was about ten feet of wire wrapped up in a ball tucked up under the rear of the RV. The wires still had to travel the length of the RV and go through the turn signal switch and everything else.

The running lights worked fine so I ended up cutting out the excess wire and re connecting everything. Then I tapped in to the turn signal/brake light wires along the frame and used them as signal to a pair of typical relays. I then ran a heavier gauge wire from the front of the RV that was fused directly to the fuse block.

I then connected the relays to the trailer light plug and the direct power line to the relays so that whenever the turn signal lines flash it opens and closes the relays. Whenever I use the turn signals on the RV I can hear the relays activate and deactivate but I now have nearly twelve volts at the light sockets I mounted in the toad's tail lights and the LEDs work perfectly. There is a slight delay when the turn signals flash leaving the lights on the RV to flash a split second before the trailer lights but that is fine.