Voltage Drop in Charging Circuit - Hi-Lo camper travel trailer forum

techjak2005 · 07-26-2019, 11:19 AM

I replaced my converter and installed a new 12 V fuse block. Everything that was working (bath fan seems to be toast) before is still working.

I left the converter plugged in overnight to check the three-stage charging and didn't think to check voltage at the battery till this morning. It appears that I have a voltage drop in this circuit. I used the existing wires and think that may be the issue, as there are a number of splices in both leads.

I read 13.2 V at the converter/charger and 12.6 V at the battery. Seems to me I should read closer to 13.2? I used 8 gauge wire from the converter to the 12 V fuse block and used the existing wires from the fuse block to the battery. The + lead appears to be 8 gauge, but the - lead appears to be 10 gauge. Would this cause this line loss?

Also, when I push the battery button on the monitor panel, all I get is a "fair" battery condition.

JackandJanet · 07-26-2019, 06:11 PM

Yes, you SHOULD have virtually identical voltages at both the converter output and the battery terminals.

With your meter, see where the drop is. What is the voltage just after the fuse block?

You MAY have a faulty ground side too. With electrical power disconnected, you could check that side for high resistance with the ohm meter. You will probably need to use a LONG jumper wire to reach both ends with your meter probes. I had to do something like that to locate a break caused by a rat chewing a stop light wire a couple years ago.

I DO think 10 gauge is big enough though. The charging Amps from the converter is not that high.

- Jack

RichR · 07-27-2019, 08:07 AM

I agree with Jack, the grounding could be the problem. I've seen where others have had that problem. The points of attachment may be open to the ravages of the weather and corrosion.

techjak2005 · 08-02-2019, 06:47 PM

Thanks for the suggestions. Yes, when I rang out the wires, I found that I had the wrong wire connected to the negative terminal on the fuse block ... so everything was working but the charge voltage was actually going through the negative lead for the lights. I realized that I got the wires mixed up when I did the install. I still have some line loss, but within acceptable limits for 10 Gauge wire. If/when I decide to do the solar mod, I will probably replace both wires from the fuse panel to the battery with 6 or 8 gauge to reduce this loss. Thanks again.