Hi there, Hope anyone can help me on this, I am new on the camping world. I just bought a 97 Elkhorn TruckCamper (cabover), it was working good, but when I am not plugged to the wall the AC outlets, air conditioning and refrigerator does not work. When i plug it it all works. So I think there is something wrong with the wiring maybe? something is not letting the current from the battery flow to the AC outlets. A car mechanic told me that maybe it only works when you are plugged, but I imagine that the Camper has a built in DC/AC converter right?Hope anyone can give me some info on what to check. Also if you have a technician that know how to fix this things would be great. I am around LA and going south in a couple of days. I have found that the RV service centers are very expensive, but any recommendation on a cheap one would be nice. Thanks!!Peter

120 volt AC items require connection to shore power.The air will not operate!The refer needs to be set on "auto" this way it runs on 120 volts AC when available and switches to LP when no 120 volts AC is available.Most rigs have a built in "converter" that changes the 120 volts AC shore power to 12 volts DC.Information: An inverter converts 12 volts DC to 120 volts AC. Most rig especially campers do not have inverters.

A/C outlets are just that.. A/C. You must be plugged into shore power or a generator form them to work. Air conditioning, microwave, etc, also require A/C power from pole or generator to work. They are not 12 volt. Most fridges do work on gas/or A/C and some even work on 12 volts, but not for long. All 12 volts appliances, lights etc require a well charged 12 volt battery to operate. Is your battery well charged?

petervicich wrote:A car mechanic told me that maybe it only works when you are plugged, but I imagine that the Camper has a built in DC/AC converter right?Hi Peter,Your mechanic is correct. The camper has a AC to DC CONverter, which charges the camper battery (if it has its own battery.)To go from DC to AC, you need an INverter. A small one could plug into your cig lighter socket and let you run a TV, dvd, etc... To run the aircon without being plugged in you'll need a decent sized generator.

Here is a typical 30AMP Power configuration for the RV trailers that might help...Power inverters to operate your high wattage appliances like the Air Conditioner and/or the Microwave will require alot of battery capacity to operate the inverter.If you want to operate the high wattage items when off the power grid then the proper sized generator is probably the best bet but then you may into generator run time restrictions where you like to camp at. Always a double edged sword it seems.Roy Ken

Thanks everyone for all the info and the quik answer, awesome!I think got everything clear now, so there is nothing wrong with the camper. I have a brand new battery and the old one is still OK, so i am going to hook them up together and will get a 1000 wats inverter to plug it on the 2nd battery so I can run a toaster, blender, etc. without having to be plugged to shore power.

AC Not running unplugged | Good Sam Community

23 Replies

petervicich
Explorer
Jun 01, 2014
Just to let you know that i got a solar panel in Baja and now everything is working fine. Thanks for all the info.

I am now in Guatemala and heading south to Peru. If you want to follow the adventure you can do it here:

www.facebook.com/KeepMovingPeru
wa8yxm
Explorer III
Feb 17, 2014
Almot wrote:

Watts = volts * amps. If something is rated 800W 120V, it means it draws 7 amps at 120V.

took me 40 years to figure this out and I have a certificate that says I know something about electronics,, But that is very simply wrong.

Watts = Volts * amps * power factor in an A/C circuit
(You are correct in a DC circuit)

So if it says it is 800 watts at 120 volt it may well draw not 7 but 8, or 9 amps..

I have seen power factors in the line of .8 (80%) but I have heard of power factors as low as near zero.. (I know the technician who fixed it you see and actually saw the machine that suffered that)

The thing was drawing amps, and you could see the watts, but the motor did not turn at all... one condenser (Capacitor) from the technician's junk box and wood was sawed.
petervicich
Explorer
Feb 17, 2014
wolfe10 wrote:
westend wrote:
So...off to Peru in a couple of days?

By yourself or with a group?

Yes, wednesday or thursday I leave LA and head to San Diego and then to Baja. Just me and my car all the way to Peru but a friend is joining me from San Diego up to somewhere in mexico.
petervicich
Explorer
Feb 17, 2014
mena661 wrote:
petervicich wrote:

I have a brand new battery and the old one is still OK, so i am going to hook them up together and will get a 1000 wats inverter to plug it on the 2nd battery so I can run a toaster, blender, etc. without having to be plugged to shore power.
If you're not sure of the condition of the old battery, don't hook them together. If the old one is not in top condition it will prey on the new one.

Coo, thanks on the tips, I will get an isolation just in case.
fla-gypsy
Explorer
Feb 14, 2014
I think it's going to be a long trip
Almot
Explorer III
Feb 14, 2014
Dennis M M wrote:
Here's some good info to help you get an idea of how things work
The 12 Volt Side of Life

This is a good source to start. Though it's got outdated a little. 19" TV would draw not 120W, but 15 or 20W if you choose wisely. Back then - yes, there was no LED TVs. In essence, 2 batts will barely support you over a long weekend without any 120V devices other than electronics. TVs and laptops have come long way in energy saving.

That battery voltage chart everybody is copying and re-printing without a second thought, while it can be way off if you use AGM batts. Again, there wasn't many AGM users when that page was written.
Dennis_M_M
Explorer
Feb 14, 2014
Here's some good info to help you get an idea of how things work
The 12 Volt Side of Life
Almot
Explorer III
Feb 13, 2014
petervicich wrote:
I have a brand new battery and the old one is still OK, so i am going to hook them up together and will get a 1000 wats inverter to plug it on the 2nd battery so I can run a toaster, blender, etc. without having to be plugged to shore power.

Like others said, these devices draw so much current at 12V that your batteries will go flat in no time.

Watts = volts * amps. If something is rated 800W 120V, it means it draws 7 amps at 120V. At 12V it will draw 10 times more - 70 amps. It means that a fully charged 140 amp-hours battery bank will go down to 50% in ONE hour. With 2 such devices running half-hour each, the bank will discharge to 50% in HALF HOUR. As it's not recommended discharging battery below 50%, it means you will have very, very little use of your 120V devices. Better not use them at all when off-grid. Or learn to live with a generator - not something that I would prefer, but many people do. From my subjective point of view, it's better and easier not to use toaster, blender and other 120V devices for a few days, than having to run a genny. Toasted bread has zero nutritional value, and blender is merely a convenience and can be substituted with juices.

Our rigs are not designed for an offgrid camping. They look like they are, but they are not.

People that made their rigs sustainable off-grid, because they wanted or had to, applied some brains and a little money to it. You may ask on TC campers forum.
wolfe10
Explorer
Feb 13, 2014
westend wrote:
So...off to Peru in a couple of days?

By yourself or with a group?
MEXICOWANDERER
Explorer
Feb 13, 2014
It would take a battery the size of a Lexus to power a roof air and hotel loads overnight. And a solar panel field that would fit atop a 53' big rig box trailer to recharge the battery just for 12 hours of use overnight. I am going to tour a massive 304 panel co-generation field tomorrow. Three Siemens inverters with a 480 volt output from what I understand. From there it goes to a 120 KV transformer and into the grid. I'll try and get some images if allowed. CFE is pretty strict about that so I can only hope. It is fenced with concertina wire atop 3 meter cyclone and has 4 marines guarding it.