Rv Only Runs AC and Outlets from Generator not Battery


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Old 07-21-22, 12:01 PM
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Rv Only Runs AC and Outlets from Generator not Battery

Hi,
I have a Terry Resort 2007 fifth wheel and I hooked up a couple 100w solar panels to the 12v deep cycle 100aH battery which is fine to charge the battery, however - the outlets and AC only run when the RV plugged into a generator.
Is this by design because the battery cannot output enough power for the outlets? If so, is it possible to hook the solar up a different way to sidestep this limitation?
Thank you.
EDIT: Also, if the RV cannot fully run off the battery, then how do other people set theirs up? Is it that you need a series of batteries wired together?
 
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Old 07-21-22, 12:45 PM
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Your solar panels and batteries are DC. The air conditioner and outlets are AC. Two different systems. An RV's batteries and DC system is designed to provide lights and power some convenience features like fans and a TV. The outlets and AC are on a separate system either powered by the generator or when hooked up to shore power.

How do other people do it... They run a generator when consuming a lot of power like running air conditioning. Most people RVing off grid and without a generator do not use air conditioning.
 
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Old 07-21-22, 12:46 PM
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Welcome to the forums.

You would need a 12vdc to 120vac inverter.
An inverter requires a lot of DC power to run large AC loads.
You would not be able to run the A/C off an inverter.

The amount of battery power required is dependent on what you want to run.
Typically a fifth wheel doesn't have much spare room for batteries so you'll be limited to which AC devices you can run.
 
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Old 07-21-22, 02:28 PM
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Thanks for the replies, I was suspecting it was something like this. I have been trying to find a manual or something that would show me a diagram of how the electrical is set up in the RV but didn't find anything for this model.

I do have spare room in the front storage compartment that is right next to where the battery is currently, so adding more batteries would not be too difficult. When you say a lot of DC power, do you mean 4-5 batteries strung together?

The A/C is not such a big deal, and the heater does run (since it runs off the propane) so that would be more important anyway. However, I would definitely like to have the outlets working at a minimum. Would an inverter solve this problem? Are there are good guides on where this would be installed and how to wire it all in?
 
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Old 07-21-22, 06:57 PM
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You'd probably want a 1000w inverter. The link below is a search page illustrating the hundreds of available models. Like anything else.... you get what you pay for. I haven't purchased one for installation in years so I'm not sure who the good guys are right now. I can check. I would anticipate spending at least $200 on a decent inverter. Some companies I've used are Heart and TrippLite.

If you have the room.... you can get the best bang for the buck using two 6v golf cart batteries. These batteries are run in series to create 12v and because they are in series they will charge and discharge fairly evenly. The inverter will draw upwards of around +90amps @12vdc with a high AC load.

With a large amperage supply bank..... charging becomes an issue.
Your solar panel with good sun will deliver about 9ah.
6v golf cart batteries
1000w inverter search
 
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Old 07-21-22, 10:25 PM
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would suggest 12 volt lifepo4 batteries they are more expensive but when you factor in lifespan not that much more not to mention much lighter.
 
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Old 07-22-22, 04:14 AM
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Many RV's have marginal running gear (tongue, suspension, frame...) so there isn't much weight margin. Some "lightweight" models are near the vehicles maximum weight when empty and the manufacturers state that even the holding and water tanks must be empty when towing the trailer. So, before adding several hundred pounds of batteries I would look up your trailer's capacities and weight limit and decide how you want to use your weight budget. You might decide that traveling with full tanks might be more important than extra battery capacity.

Like Alan73 mentioned. There are lightweight lithium batteries. They are considerably lighter than lead batteries and they can be charged much faster. The fast charge is a big benefit if you charge off a generator since you can cut your gen run time by about 75%. Instead of running your generator for 4 hours a day to top off the house batteries you might do it with only an hour of generator time. The drawback is the expense. You will need a new charger compatible with lithium batteries ($) and then the batteries are VERY expensive.

When shopping for an inverter I would pick a full sine wave model. They are more expensive but they tend to be higher quality than inexpensive modified sine wave models and have higher efficiency. There are some devices that don't work at all or work poorly when powered by a chopped sine wave but with a pure sine wave inverter you're assured that whatever you plug into the outlet will work.
 
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Old 07-22-22, 08:40 AM
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Thanks for the recommendations, much appreciated.

I have a 100ah lead acid battery and I think it might be enough for now, I could always upgrade later. The two solar panels are wired through a 75v|15A charge controller so they can charge the battery ok throughout the course of a day.

As far as installing the inverter, this has to get wired into the fuse box/circuit breaker? This is about the limit of my electrical knowledge (which is very limited as is). I do have a plug in the RV for shore power (I think 30A) so I read something about needing a transfer switch and wire the shore power and inverter through the switch so that only one gets used at a time. Still looking around on YouTube for a straightforward guide

In the meantime, I actually found a cheap 400w inverter in my house that I had gotten for my car years ago and I'm thinking about just having it hook up to the battery and run an extension cord for now, just to have some working outlets.

Thanks again for all the replies.
 
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Old 07-22-22, 10:08 AM
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You will need to figure out how you want to wire your trailer. One option is to run new wires in the trailer for some outlets fed by the inverter. The existing outlets would remain the way they are now, only powered when hooked up to shore power. Since they are two totally separate systems they can both be powered at the same time.

Another method would be to install a transfer switch. This would allow your inverter to feel all the existing 120 VAC wiring and you wouldn't have to pull new wires. A way to simplify that is to install an outlet on the output of your inverter. Then plug your shore power cord into the inverter socket. Then if you you want to run on shore power you unplug the cord from the inverter socket and plug into shore power. Basically the cord and socket is a poor man's transfer switch. Since you can't plug your shore power into two places at once it protects you against accidentally powering the trailer with both (which could end badly and expensively).
 
 

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