DC to AC power inverter

JCamper · 08-08-2013, 02:26 PM

Okay I apologize upfront if this is a redundant topic but I have searched and can't see a match thread to my specific issue.

The short of it... I want to be able to run 2 TV's off the DC 12 batteries on my 3150 BHD (only for a few hours). And also on occation be able to accommodate a CPAP all night.

I know that there are inverters out there that would be recommended, but my question is, is it possible to somehow hook up an inverter to the batteries and put the power back through the coach via the 110 AC outlets?

I want to avoid drilling and running wires everywhere if at all possible. The TV's are on opposite ends of the rig. And the one in the back has no existing DC plug.

Suggestions?

garbonz · 08-08-2013, 02:53 PM

Yes you can do that, by wiring the inverter into a switch that takes both the shore power and inverter power and chooses between them. HOWEVER, many don't do it this way because it puts ALL the 110 circuits on the inverter and you would have to switch everything else off every time you did this.

It can be done tho.

Lots of options and pros and cons to inverter hook ups. I don't have one yet for the TV but am thinking about it. My current plan is to put 2 specific outlets, one by the TV and one in the kitchen powered by an inverter located right by the battery. Maybe a winter project, if Santa is kind.

BarryD0706 · 08-08-2013, 02:55 PM

What is a CPAP?

12v TVs would be more efficient than the inverter route.

The problem with what you want to do it somehow preventing the various other 120v appliances in your RV from using power from the inverter. Things like refrigerator, microwave clock, CONVERTER. If you can address that, you can probably find a transfer switch somewhere to do what you want.

JCamper · 08-08-2013, 03:06 PM

Thanks for the responses so far.

Maybe a stupid question but would an adapter from my shore cord plugged into an inverter at the battery put the 12V to the AC outlets? Or am I dreaming/wishing?

BTW CPAP is a sleep apnea machine for the ol man.

JCamper · 08-08-2013, 03:09 PM

Quote:

Originally Posted by garbonz

Yes you can do that, by wiring the inverter into a switch that takes both the shore power and inverter power and chooses between them. HOWEVER, many don't do it this way because it puts ALL the 110 circuits on the inverter and you would have to switch everything else off every time you did this.

It can be done tho.

Lots of options and pros and cons to inverter hook ups. I don't have one yet for the TV but am thinking about it. My current plan is to put 2 specific outlets, one by the TV and one in the kitchen powered by an inverter located right by the battery. Maybe a winter project, if Santa is kind.

The TV's would only run at night for a couple of hours after the 10am all gen's off curfew. So I wouldn't be running anything else other than maybe a few lights in the coach. The CPAP would be an all night thing if possible. I think it only draws like 15 amps total

BarryD0706 · 08-08-2013, 03:09 PM

Quote:

Originally Posted by JCamper

...
Maybe a stupid question but would an adapter from my shore cord plugged into an inverter at the battery put the 12V to the AC outlets? Or am I dreaming/wishing?

Yes, if you can address the other problems I mentioned, that will work.

JCamper · 08-08-2013, 03:12 PM

Thanks BarryD0706 I think that would be an inexpensive easy route, I'll give it a shot.

BarryD0706 · 08-08-2013, 03:13 PM

15 amps AC is a lot (and a lot more than TVs). That would require a 2kw inverter and would draw 150 amps from your battery. You wouldn't be able to do that overnight without a much bigger battery system.

JCamper · 08-08-2013, 03:19 PM

My bad! 30 watts at 120 volts so actually 0.25 amps constant

wrapperman · 08-08-2013, 03:19 PM

Xantrex offers a transfer switch that will do what you want.
They are about 60 bucks.
You should use one of their inverters to make the job easy, but not necessary. I plan on doing just what you are talking about. I plan on installing my inverter/transfer switch next to the breaker panel inside the cabinet. Be sure you have enough air circulation around it. My coach batteries are about 7 feet from the breaker panel. I am going to disconnect the circuit running to the both TV's and connect it to the inverter. This setup is what Forrest River uses for the residential refridge.
If you have any questions feel free to ask.
I am going to do this so my wife can watch a little TV while going down the road and not having to run the generator.
One thing you may want to do is invest in better batteries. Mine came with 2 small 12 volt batteries that don't last but 4 hours running the refridge. Just do your homework on battery size needed.
Good luck

wrapperman · 08-08-2013, 03:28 PM

Just read your last post.
Running an inverter through your shore power cord will have issues because of your converter is hooked to the shore power after the transfer switch. Doing this would then be needing power for the transfer switch and the power converter and then you are trying to invert 12 volts to 120 volts while trying to charge the batteries and inverting power. One big loop and many problems you could encounter like a floating electrical charge somewhere. Not good for electronics.

RPAspey · 08-08-2013, 07:38 PM

cheapest way to do what you want to do, is to plug the shore power cord into the inverter. BUT, as others have pointed out, you will need to make sure any unneeded 120 volt devices are unplugged or it's breaker opened.

Some examples: the breaker for the converter MUST be turned off. The fridge must be on propane only (and the condensate heater off or disabled) The water heater's electric element must not be on (gas only). I'm sure there are other things I'm not thinking of.

KootenayWC · 08-08-2013, 08:57 PM

I hardwired a 1500w inverter into the new trailer we bought this spring . I bought an automatic transfer switch which just happened to be made by the same manufacturer as the power center, turned out it was designed to piggyback on the back of it! When dry camping I turn off the breakers for the A/C, water heater, microwave and converter. There's no breaker for the fridge so I just make sure its set to gas. I had to add a breaker for the converter, as it was getting power from the circuit supplying the 110v outlets. Now when dry camping we can turn on the inverter and watch TV, as well as all the 110v outlets are powered.

Steve

wrapperman · 08-08-2013, 09:26 PM

As I mentioned in my post earlier xantrex already offers a solution for 60 dollars. You wire it in to the inverter and it automatically switches the power from shore power to battery power inverter. No special wiring needed. Hook it up like Forrest river does for their residential refrigerators. Problem solved like a professional. No need to turn or switch anything off or on. Don't have to worry about any appliances or items on or off.
Search ebay or amazon for "xantrex transfer switch".

garbonz · 08-08-2013, 10:26 PM

Quote:

Originally Posted by wrapperman

As I mentioned in my post earlier xantrex already offers a solution for 60 dollars. You wire it in to the inverter and it automatically switches the power from shore power to battery power inverter. No special wiring needed. Hook it up like Forrest river does for their residential refrigerators. Problem solved like a professional. No need to turn or switch anything off or on. Don't have to worry about any appliances or items on or off.
Search ebay or amazon for "xantrex transfer switch".

Still need to switch the converter and other 110 volt loads off, or you will suck the battery dry.

KootenayWC · 08-08-2013, 10:32 PM

Quote:

Originally Posted by wrapperman

As I mentioned in my post earlier xantrex already offers a solution for 60 dollars. You wire it in to the inverter and it automatically switches the power from shore power to battery power inverter. No special wiring needed. Hook it up like Forrest river does for their residential refrigerators. Problem solved like a professional. No need to turn or switch anything off or on. Don't have to worry about any appliances or items on or off.
Search ebay or amazon for "xantrex transfer switch".

Not quite that simple. All any transfer switch -Xantrex or otherwise - does is switch from shore power to another power source (inverter or generator). It senses where the power is coming from and switches to that source. It still sends the power through the power center, thereby potentially powering the whole trailer. That's why you need to shut off breakers. The only way you don't have to worry about appliances or shutting off breakers is to add a sub-panel to separate out the circuits you don't want the inverter powering. You can be certain Forrest River is doing something slightly more involved than simply adding a $60 transfer switch.

**Herk7769** · 08-09-2013, 05:59 AM

Inverters are a huge demand on the battery. I would not install a 400 watt one without at least 150 AH of battery bank (12 12 volt OEM batteries); and even then only minimal television use.

There is much more expense to this modification than meets the eye.

SimchaSabre · 08-09-2013, 06:57 AM

I installed a 800W imverter right next to the battery than ran 12-3 to an recepticle that is only used for the inverter. We then use extension cords in the camper for the TV or fans which is mostely what we use it for. Not the best solution, but we don't use it all that often.

wrapperman · 08-09-2013, 06:58 AM

I may not have myself clear enough. I plan on disconnecting only the circuit running to the 2 TV's. I the panel box. This inverter would then only be running that dedicated circuit and nothing else. Forrest River has a dedicated line only for the refridge and nothing else. The xantrex transfer switch connects after the inverter to switch to inverter when shore power is turned off. If nothing is turned on for that circuit then the inverter would only draw its idling amps. I was assuming the gentleman had a dedicated circuit for just the TV's.
he still needs a strong battery pack.

JCamper · 08-09-2013, 11:03 AM

Thanks KootenayWC by chance where did you hard wire your inverter? I see another member on here went to the breaker panel, but mine is tight on space so looking for another option.
Also I still like the idea of killing the trailers converter at the breaker and just running shore cord to the inverter. I won't be running the water heater, fridge, or anything other than 2 TV's and possibly a light or two at most.

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