Community Forums

kennyb79 · 03-25-2012, 08:49 AM

I'm a newbie to the motorhome...but not to camping. I just bought a new to me 94 coachmen 29 footer. I'm still pretty confused as to how the power inverter/shore power/and generator power all work and what can be run.

I'm all set with the concept if its plugged into shore power everything will work. but when I'm traveling down the road, I was told that the generator needs to run for the roof A/C and microwave to run. He also told me that he had a TV and DVD player plugged in and they ran the generator for those as well.

my question is what appliances can I plug in and run going down the raod without running the generator. Won't a TV and dvd player work off the inverter? can I run a coffepot as I'm driving or is that to much of a draw?

Thanks for your help....

RJay · 03-25-2012, 09:01 AM

The answer to your question depends on the size, number and type of batteries you have powering the appliances. The size of your inverter will also be a limitation to how many appliances you can run at the same time.

Your batteries are rated in amp/hours. And they shouldn't be depleted less than 50% before recharging as batter life will be lost.

If you know the amperage draw of the appliances divide that into half the amp/hour capacity of your batteries and that will tell you how many hours you can safely operate the appliance. For multiple appliances run at the same time just add the appliance amps together and divide to half the battery capacity.

garym114 · 03-25-2012, 09:15 AM

You probably do not have an inverter if you were told the TV and DVD player requires generator power. An inverter operates from battery power and produces 120v AC.
The only power you have going down the road without the generator is 12v DC.
You have a converter that takes 120v AC and makes 12v DC to operate 12v loads, lights, heater blower. The refer, water heater and AC thermostat need 12v to operate. The converter also charges the batteries.
You can add a small inverter to operate small AC loads like TV and DVD. It would take a large inverter and more batteries to operate the microwave and coffee maker when you do not have 120v AC power.

Aguyfromcalg · 03-25-2012, 09:25 AM

Hi and welcome:
You will need to run your generator to use your roof A/C unless you are plugged into shore power. When you are traveling the chassis and house batteries should be charging by your motors alternator so you should be able to use whichever plugs are powered by your inverter.
When camping I would monitor the house battery level to not deplete them
It won't be a bad idea to play with the systems while you are home to know what each does.
I hope this helps.

BFlinn181 · 03-25-2012, 09:26 AM

Most electrical devices have the watts listed. To convert watts to amps, divide the watts by the voltage. (110) A coffee maker listed as 1200 watts: 1200/110 = 10.9 amps. If you do this for the devices in your RV, you can see how much of a draw each item is.

Do not try to use an inverter at near capacity, it will shorten its life. Most inverters will list 2 ratings, a continuous wattage and a surge wattage. Don't exceed the continuous rating.

To operate the roof AC on the road, its power requirements will demand the generator, an inverter/battery bank will not handle the load.

kennyb79 · 03-25-2012, 09:46 AM

so I've been playing with things a little. If I'm plugged into shore power, I can hear my converter humming, and my microwave lights up (I didn't try the A/C) however nothing else works unless I turn on my battery disconnect switch...then all my lights come on. Also, when I turn my fridge to auto, the LP light illuminates, not the electric light.

I'm sure after a while this will all be old hat to me...right now its just confusing.

RLKBOB · 03-25-2012, 06:13 PM

I just bought a 1995 Coachmen 29 footer in Dec. Learned a lot over the last couple months. The lights are all 12 Volt DC thats why the disconnect needs to be on for them to work. As stated unless somebody added one you don't have an inverter so you can only power 120 volt AC loads if you're on shore power or the Gen is running.
I'm in the process of upgrading my Battery system from one series 24 battery to (3) series 27's, adding an 1800 watt inverter and solar. This site has been a great source of info.

kennyb79 · 03-26-2012, 08:36 AM

I agree, this site is full of people that want to share their knowledeg. I guess I was confusing converter with inverter. I have a couple of inverters I used to use in my conversion van to run the TV's I guess I'll just do the same now. Mine is a 94 coachmen 29 footer so were pretty similar RLKBOB

seanoliveira · 03-27-2012, 08:13 AM

Hey guys. I guess I'm in a similar boat as well. I just purchased my first RV, a 1993 Gulf Stream Ultra 29". I'm also a little newbie to the fine nuances of the RV electrical system but it's great to learn from those who've been there. I'm actually still in the process of trying to find my battery disconnect switch. Getting some fresh belts on the engine so the search will have to wait until they're done with her. Good Luck with your Rv'ssss

RLKBOB · 03-27-2012, 08:14 PM

My battery disconnect switch is right inside the house door on the left side near the electric step switch.

eurosteve · 03-28-2012, 03:37 AM

Hi - another nooby here. You stated - "The lights are all 12 Volt DC thats why the disconnect needs to be on for them to work." So, if you're plugged in with the shore line and you want to use the 12v lights in the coach, you need to flip the battery disconnect switch. Can you explain what the battery disconnect switch does? Does this mean that the battery won't be charging while on shore power?

RLKBOB · 03-28-2012, 10:18 AM

In that case you will still be charging the battery from shore power through the converter. The battery disconnect just shuts off most DC loads to keep from draining the battery(ies). I assume most people only use this when the MH wont be used for a while. The only DC load I've found that still works with the battery disconnect open(disconnected) is the elec entry step b/c it comes directly off the battery and doesn't go through the DC fuse panel(at least that's how it is on mine).

EricGT · 04-12-2012, 07:14 AM

This was new to me the first time I rented an RV. I could not figure out why the coffee pot wouldn't work while driving down the road.
I don't have a battery disconnect on my RV.
But the easiest way to explain my set up is that everything will work when the RV is plugged in. If you want heat or to use the stove you must also have the propane tank valve open. You will need at least 30 amp service to run the a/c.
Some water heaters work on electric and/or propane. I believe most fridges also give you the option.

When driving down the road, it is the same as boondocking. The only thing that will work is heat, lights, water pump, and whatever is running through an inverter. We have our stereo, t.v., DVD player, security system plugged into an inverter. That way they are always powered so long as the batteries have a charge.

If you want to use any electrical outlets, microwave, a/c the generator must be running if not plugged in.

That is how my Rogue works at least.