Dim lights on DC current

I recently purchased a 2004 trailmanor (2720). I camped in it using AC at a campground for three days. Everything worked fine. I had a trailer brake controller installed on my truck, and paid an extra $10 for a curcuit that would charge my trailer batteries from my truck alternator when traveling. Since returning home I set it up running on DC to check everything out and become familiar with how everything works. (I am a novice to RV,s.) Last night I checked out my lights inside the camper. They are extremely dim. So dim that you couldn't possibly read by them. Also my am/fm receiver won't work, which was fine on AC. The camper has two new 12v batteries, which I assume should have a strong charge. My question is what should I be able to expect on DC? My truck dome light is bright just drawing off the battery. I would expect the same in my trailer. Could someone advise? Thanks.

Need a little more information.
You said you paid an extras $10 for a circuit to charge the battery while driving. I assume that what this was is a heavy duty wire from the fuse box back to the +12V pin on the connector on the TV. If it is anything else, you might want to change it. It is not clear, but I think you are saying you did this test with the TV connected to the TM. You don't say what your TV is which is important as some TV's have a circuit that disconnects the power from that 12V trailer circuit when the TV is not running. This prevents killing the TV battery while you stop to eat lunch. Try the same test with the TV running. If the lights are fine, then you have the protection circuit. That being said, there is still a problem if you have two new fully charged batteries and your lights are dim. Do you have a battery shut off switch? Is the fridge on DC? if none of these, use a meter to check the voltage of the batteries ( individually) when not connected to the TV. Unless the wire that the dealer added to charge the TM batteries is very heavy #10 or above, you probably will not get much charging if anything is on in the TM. Try these and let us know what you find.

My TV is a 2005 Silverado. I will test my batteries with my volt meter. You mentioned something that made me think. I did leave the TM connected to my truck when I returned home. It was connected overnight. Thanks for the reply.

[ShrimpBurrito]

Your batteries are dead or discharged. When you plug the TM into AC, the converter generates DC power the appliances run off of instead of the battery, so that's why the lights work great when you're plugged in.

I guarantee you that nothing your dealer did for $10 will allow you to significantly charge your TM's batteries. Could they charge it a little? Sure. Maybe. Should you expect them to get a full charge after your few hour drive home? Definitely not -- not even close. And you may not have even been getting any charge if you had your fridge on. In fact, it may have had a net discharge.

My guess your $10 was for a fuse or relay the dealer dropped in, which simply provided some power, as opposed to none. They definitely did not add any wires for that price.

You don't say what year your Silverado is, but many newer model vehicles have circuitry in them that prevents any power from being drawn from the TV battery through the towing harness. In such a case, leaving the TM connected to the TV overnight would not have any effect on the TV battery.

Have you tried leaving your TM plugged into AC for 24 hours, and then unplug and test the lights? That would be the first thing I would do.

Dave

[Barb&Tim]

In our 2003 GMC The trailer battery charging fuse(which had a dummy plug from the factory installed) in in the fuse panel under the hood and was labeled "Stud #1". To activate Trailer battery charging, I removed the dummy plug and replaced it with a 40a Maxifuse. I assume a 2005 chevy truck might be similar.

Tim

The guy who installed the controller said that all it was was basically a fuse for the $10. Just an add-on sale that they charge to make a few bucks I imagine. I tested the batteries and one read 9.6v on my multimeter. The other read 10v. I am currently charging both with battery chargers. My concern is that in 3 days of camping with an electrical hookup you would think that the batteries were fully charged. Such charging is automatic right? I don't have to flip a switch somewhere? Then, my truck alternator should have been able to keep them charged during my return home. I did have my frige and fan on. I will get the batteries charged. What I would like to know from other owners is what can I expect for electrical supply if I have no AC hookup available? Can I expect hours of readable light, as well as listening to the radio? Plus keeping the frige cold?

[Bill]

RBauer posted

What I would like to know from other owners is what can I expect for electrical supply if I have no AC hookup available? Can I expect hours of readable light, as well as listening to the radio? Plus keeping the frige cold?

If you have no AC hookup, and your tow vehicle engine is not running, then you MUST run your refrig on propane. If you run it on Battery (which is what it sounds like you did), it pulls A LOT of current, and will very quickly deplete your TM batteries.

While you are towing, you can in theory run the refrig on battery, and the tow vehicle's alternator will provide the power. This works with some tow vehicles, but does not work on others (such as my Ford 2002 and 2007 Explorers). The problem (if there is one) is that the wire size in the tow vehicles is too small. Some tow vehicles are not affected - I think PopBeavers has one of the good ones. I installed new and heavier wires in my first Explorer, and it cured the problem.

If you are plugged into AC power, at home or in a campground, then you can run the refrig any way you want. If you set it for AC or propane, then it runs directly on those fuels. If you set if for Battery operation, then the trailer's converter supplies the needed power, as ShrimpBurrito mentioned in his first paragraph.

Once you have chosen the power source for the refrig, you don't have to do anything else. No switches to set or throw or connect or disconnect.

Hope this helps.

Bill

[Barb&Tim]

Originally Posted by rbauer

Can I expect hours of readable light, as well as listening to the radio? Plus keeping the frige cold?

For light and radio it really depends on the condition of your batteries.

The fridge pulls way too many amps on DC to use on just your TM batteries -- use propane instead.

DC is only useful while towing assuming you have a good charging circuit coming from the TV.

Tim

I think we may have discovered the culprit. I did have my frige and fan on the DC setting overnight when I got home. Thanks to all for your input.

My TV is a 2005 Silverado. The wiring for the 12V connection to the TM is there it just needs a fuse/breaker. That being said. the gauge of the wire running from the batt to the connector is not large enough to do anything but add a trickle charge to the batteries if nothing else is running in the TM.
As far as I am concerned, Unless you add a separate high current voltage convertor to your TV, the DC setting on the fridge is useless. If you want it to run the fridge during a several hour trip to a campground where you will immediately connect to shore power, you might be OK. Otherwise IMHO useless.