This is such a silly question that I would like to know your password so that I could post it under your name! Here goes: I plugged my new TT up to shore power (my garage) and disconected the battery to check for power. Checked the lights adn all was good. Reconnected the battery so that I could recharge it. I disconnected the 110v shore power a day later. The electric clock inside the TT would not work until I plugged the TT back in. Does the battery not have enough power to run outlets? Is it as simple as a 12v battery not being able to power a 110v outlet?
I told you it was a silly question! Quit laughing!
Out numbered 4:1
1999 F350 PSD 7.3L Dually
2008 Cedar Creek Silverback 35L4QB
Mak'n memories with the kids...and Bosco the Chocolate Lab
Having two different electrical systems on a vehicle/trailer can be complicated.
120 volt AC current (house current) is wired to run many things in your trailer. This includes outlets, A/C,and likely a converter which "converts" 120 volt AC to 12 volt DC/battery power.
To answer your clock question, you will need to find out of the clock runs on 12 volt DC or 120 volt AC. If on 12 volt DC, then either you have a connection problem, main battery switch off or a dead battery. Buy a good digital volt meter (which you will use for many things around your trailer). Check voltage at the battery. A fully charged 12 volt battery will read 12.8 volts DC. A 50% discharged battery (as low as you want to take it for good battery life) will read around 12.2 volts DC. Using the battery below 12 volts will really shorten its life.
Unless you have an inverter which takes 12 volts DC from a battery and makes 120 volts AC, you will not be able to run 120 volt AC (house current) items when not plugged into shorepower (unless you have a generator). And even with an inverter, large loads such as the A/C can not reasonably be run from an inverter.
It isn't a silly question as many folks just starting out don't know that there are two (yup, two) complete side-by-side electrical systems in an RV. You've identified them in your title. There is the 110V AC system and the other is the 12V DC system.
The AC system is powered by the extension cord that you plug in to shore power and your electric clock, microwave oven, air conditioner and other AC-only items run by this.
The DC system is powered by your batteries in your RV. It powers many of the lights, the water pump, and other systems.
When you plug in to shore power, there is an AC to DC converter which recharges your batteries (though not like a true battery charger) and supplies DC power to your DC items.
There does exist something called an "inverter" (not a standard part on an RV, but you can buy one or more of various ratings) which converts 12V DC to 110V AC (to run your electric clock, or the microwave, for example), but at the expense of running your batteries down more quickly than normal. A portable generator can also provide AC power when not plugged in to power your TV and microwave.
You need to identify which systems are DC powered and which are AC powered. There are also a number of books available that describe more on this topic. My favorite is "RV Electrical Systems: A Basic Guide to Troubleshooting, Repairing and Improvement" and is available from Amazon.com.
Hope this helps.
*This Message was edited on 30-Mar-03 08:58 PM by LLeopold*
2001 Dodge Ram 2500 Diesel Quad, SWB, 3.55:1, Rhino Lining
2000 25' Mallard M-23 5M 5th Wheel
Husky 15K w/EZ slider
Wen PowerPro 3500 Generator in a sound box
And I continue to tent camp!
RVs have three: The automotive (chassis) 12 volt system, the "house" 12 volt system, and the 110 volt system. The automotive electrical system has the prime function of providing a burst of 12 volt power which will start the engine. After that, the vehicle's alternator takes over and supplies all the electric current for other uses (lights, horn, stereo, etc). The coach has its own 12 volt system, but this one's based on deep cycle batteries -- these are designed to put out a relatively small amount of electricity for a longer period of time. How do the house batteries get recharged? When you run your RV, the alternator will recharge not only the chassis battery, but the deep cycle house batteries as well.
For maintenance, be sure to keep water level up inside the batteries. Use baking soda and water to keep battery terminals clean. Keep in mind even when you're not using the RV, there is still a small electrical drain going on. Incidentally, in a pinch you can use the house battery to start the engine if the chassis battery should go dead. Happily there's an "isolator" which keeps the chassis battery from discharging into the "house". So if you leave the lights on too long in the "house", you won't drain your chassis battery.
The 120 volt system comes on easily when you plug into the campground's hookups. Also, most RVs will automatically recharge the house batteries whenever you're plugged into shore power. Also, the "converter" will automatically transform some of the 120 volt power to 12 volt electricity so you can run all your DC appliances. Incidentally, an "inverter" does the reverse -- it will take 12 volt power from the battery and change it into 120 volt AC power. But it's really only for smaller electric loads. It can't be used, for example, to run an air conditioner. Keep in mind it does drain your battery if you use an inverter!
Chassis Electrical Systems
This is the vehicle electrical system. It includes the vehicle battery, charging system, ignition system, instrument panel and controls, and the headlights, taillights, turn signals, and other vehicle lights and accessories.
Chassis Bulbs And Fuses Replace bulbs with equivalent types as marked on the bulb.
Fuses for the chassis electrical system are located under the instrument panel on the left. Additional fuses may be located under the hood. Others may be found in the 12-volt power leads on the related equipment and accessories.
12-Volt Coach System
All 12-volt lighting fixtures, convenience outlets, 12-volt powered vents, freshwater pump, and 12-volt accessories are included in this system.
The 12-volt power is provided by special deep-cycle, high capacity coach storage batteries. Power is also provided by an AC/DC power converter for use when the motor home is plugged into a 120-volt power source. Battery charge is maintained by the motor home engine alternator, or by the converter.
NOTE. All living area radios and tape decks draw from the chassis or coach battery, and extended usage when not traveling may discharge them.