Forum Discussion

memilanuk's avatar
memilanuk
Explorer II
Jul 01, 2018

Tracking down amp draw

So... in another thread over in the 'Travel Trailer' forum about running 15k BTU A/C units on gen sets, I'd mentioned that we tried it last weekend on a Champion 3100, and it worked - barely - with the A/C in our '18 Keystone Cougar 28RLSWE.

It was a struggle to get the gen set working to begin with, because when I started the generator with (I thought) everything in the trailer off, it promptly gave a flashing red 'Overload/Trouble' light and no output. Had to shut the unit off, un-plug the cable to the trailer, and then get the generator back up and running, with econo mode off, and *then* plug in the shore power cable to the trailer... which seemed more than slightly odd, as that wasn't the case on the *last* trailer ('13 Salem T21RBS).

To add to the mystery/irritation, once we got it running, the only way to start the A/C without tripping the generator was to start the fan first, separately... then after a minute or two, start the A/C. Done that way, the generator would load up and purr away. Never dropped into econo mode, and it was enough of a PITA to do things in the right sequence that the wife just suffered thru the heat rather than start the A/C while I was away. Luckily, she likes it warm!

The second night we moved to a site with water and power (temps were projected to be considerably warmer the next day). After everything was setup and the A/C running, I checked the new PI EMS-PT30X and it showed 117v, 60H, and 21A... which by my math works out to about 2450 watts... which seemed a little high for just the A/C running.

Now, that we're home, I have some time to do some sleuthing before we
go out on our two-week summer road trip. Turns out, there *were* two other potential culprits. One, even though the control panel says 'DSI Gas Water Heater', there is a little tiny rocker switch inside the access panel - pretty sure its actually gas/electric. Good to know; kinda wish the dealer had *mentioned* that during the walk-thru...

That said, it was in the 'OFF' position. So that wasn't it.

Went to plug in the trailer to a 30 amp outlet that we have on the far corner of the house - I'd picked up a 30' extension cord just so I could reach it. Good thing I plugged the new PI EMS-PT30X in first - it showed a reversed hot and neutral wire. Add that to the fix-it list. Plugged the trailer into a regular 15 amp GFCI outlet instead - so no testing the A/C. Went inside, turned the fridge to 'auto', went out and checked the EMS... showed 9A, just sitting there No A/C, no fan, no microwave, nothing plugged in.

Turned the fridge back off... load dropped to 5-6 A. Okay, so the fridge accounted for 3-4 A, double-checked that the water heater is still 'OFF'... checked the breaker panel. Not much there, other than A/C, microwave, converter, GFCI, and 'WH' (sheesh :S ).

Turned off the converter, and immediately the interior LED lights dimmed slightly. Not a lot; you might not notice if you weren't right there at the time. Checked the EMS... load is down to 0-1A. Hmmm...

Turned the converter back on, and checked the battery on the control panel - shows 'F'ull (very technical and accurate, I know). Checked it both with the converter on and off, same reading.

Turned the battery disconnect switch off, and checked the EMS again (with the breaker for the converter at the main panel closed in). Back to 0 amps.

So for some reason the converter is sucking up 5 amps of power just trying to shove voltage into an already charged battery...

At some point I'm going to have to dig out my multimeter and see what the actual battery voltage is both while being charged, and just sitting. These are *supposed* to be two brand-new 12 volt batteries...

Any thoughts about where else to look next? Is that normal current draw for a stock/OEM converter / charge controller? Would the 9A of load (converter + fridge) be enough to cause an overload fault on the Champion 3100 during startup? To be honest, if I (or the wife) have to strip the breakers on the main panel just to start the generator, or else monkey around with plugging in the cable after starting the unit... I'm not going to be real happy. Options?

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,190 PostsLatest Activity: Jan 23, 2025