Voltage Drop between battery and 12 volt outlets

[kdhook46]

I have a 2006 2720 which I bought a year ago. Almost like new. Six trips last summer. Two so far this year but it's time to dry camp. Even if I can force a plug from my inverter into the two 12 volt outlets, the inverter doesn't work. Works great if I'm plugged into juice at the campground but not when disconnected. Replaced one of the outlets so it's easier to insert the plug. Batteries are reading 12.65 at the battery but the voltage at both 12 volt outlets is 1.5 volts lower. Any ideas?

[gonzo628]

bad ground?

[Larryjb]

Are you using the same meter to measure the battery and 12V outlet voltages?

[tentcamper]

I would clean the ground connection at the frame from battery to frame and from converter to frame. also replace the glass fuse with a blade type fuse if you have a glass fuse.

[rickst29]

The most likely source of voltage drop (by far!) is the cylinder-type battery fuse internal spring having rusted over time, and turned into a significant "resistor". A nice waterproof blade fuse (or a waterproof automotive "circuit breaker") would be a good replacement.

[BrucePerens]

How much are you trying to pull from the inverter? At 10 amps, number 18 copper wire, two conductors, would drop 1 volt in 15 feet. You actually have a greater length than that (possibly thicker than number 18, I don't know what gauge Trailmanor uses) because there is a run from the battery to the converter, and from the converter back to the DC jacks.

This is why I ran 2/0 welding cable from the batteries to where I have the ham radio. That's a bit of overkill, but it works.

[rickst29]

Bruce mad a great point. But, the 12-volt outlets have another problem: The assemblies contain small fuses which limit the maximum power (to about 80W, IIRC). To get more power into an inverter, you need to hard-wire as Bruce has done, or you need to replace the Wineguard outlet plates with bigger-wired, bigger-fused "socket adapters". (I did that to all of mine, they were also "too tight" before I replaced them.)

I feel that it's a "bad idea" to push more than 10A through on of those spring-loaded sockets - and most brands of cars and trucks agree, marking them at '120W Maximum', with 10A fuses.

[scrubjaysnest]

When we had our 2720SL I upgraded to 10 AWG wire for the 12 volt outlets. Problem gone for running the inverter.

[kdhook46]

Thanks for the various ideas. As I mentioned, the inverter wouldn't work because of low voltage which is now solved. I decided to simply put new fuses in and see what happened. Voila! Everything is now fine. The old fuses still looked good but perhaps there may have been some corrosion buildup over 10 years. Everything is now fine. And the new 12 volt outlets I picked up from Amazon work great. It's easy to now insert the 12 volt plugs. Thanks again.

[Padgett]

My inverter is in the underbed compartment, 24" of #4 from the GC2s. Have to remember you need to multiply the device current by 12 to get the DC current needed.

My inverter is 1kw continuous so I designed the system for 100A.

See here.