Confused about inverters

[VegasVanGuy]

I have a motorhome and I'm doing research on solar. Most of Bob Wells articles are on van conversions and the inverter has 110v outlets. So for a motorhome you already have 110v outlets, how do you wire it into that system?

 

[Optimistic Paranoid]

It's called a Transfer Switch.

Large commercial motorhomes frequently have THREE sources of ac power - a shore power connection, a built in generator, which often runs off the vehicle's fuel tank, and a large inverter.  The output of all three of them is wired to a switch - often an automatic switch that senses which source is active - and the output is then fed to the input of the circuit breaker panel.

For simpler rigs, you can buy an inexpensive manual switch that will do the same thing.  Here's one from the world of boats:

http://www.sterling-power-usa.com/sterlingpowerusamanualcrossoverswitch-1.aspx

Again, you would have two or three inputs, and one output going to the fuse box or circuit breakers.

 

[Almost There]

I have a motorhome and I'm doing research on solar. Most of Bob Wells articles are on van conversions and the inverter has 110v outlets. So for a motorhome you already have 110v outlets, how do you wire it into that system?

Unless you or the previous owner has ripped out the inverter, it's already there.

For solar you only need to be concerned initially with the solar panels, a charge controller, the wiring from the solar panels to the battery, etc., and probably a battery monitor if you don't already have one.

Depending on how much power you're wanting to store (and use), you may also need to figure out how to beef up the battery system. Most RV's are traditionally under powered with battery capacity since the manufacturer really expected you to spend most all your time in an RV park where you are hooked up to shore power or alternatively, running your generator as you are using electricity as opposed to generating it from solar and storing it for use later.

 

[VegasVanGuy]

Unless you or the previous owner has ripped out the inverter, it's already there.

For solar you only need to be concerned initially with the solar panels, a charge controller, the wiring from the solar panels to the battery, etc., and probably a battery monitor if you don't already have one.

Depending on how much power you're wanting to store (and use), you may also need to figure out how to beef up the battery system. Most RV's are traditionally under powered with battery capacity since the manufacturer really expected you to spend most all your time in an RV park where you are hooked up to shore power or alternatively, running your generator as you are using electricity as opposed to generating it from solar and storing it for use later.

Hmmm. I agree that I need to replace the battery system. The RV is only 22ft. The 110v sockets/microwave/AC only work when the generator is on or on shore power. This makes me think it has a switch but not an inverter. Thoughts?

 

[BradKW]

Hmmm. I agree that I need to replace the battery system. The RV is only 22ft. The 110v sockets/microwave/AC only work when the generator is on or on shore power. This makes me think it has a switch but not an inverter. Thoughts?

That sounds quite likely.

What is it you are hoping to power from your new solar/battery/inverter setup? If the RV was built with only shore and generator power in mind, it's also quite likely that the current 110v appliances may not be appropriate for the solar system you have in mind. Or, more accurately, the size of the solar system you're thinking about.

So it may be that the simplest approach would be setting up the solar independent of the existing 110v system, and running a power strip from the inverter to power the 1 or 2 items you prioritize. For example, expecting to power the AC unit probably isn't going to work out from a solar/inverter. That's in addition to any 12v items you have/upgrade/add. The more details you give, the more helpful the input you'll get...

 

[highdesertranger]

it sounds like you don't even have an invertor. what do you want to run off the invertor? might be better to just run an invertor separately and not through the existing outlets. highdesertranger

 

[ZoNiE]

You're going to need to separate the 110v outlets from the circuit breaker panel and put in an auto switch between them and the breaker panel so when the Genny or shore power are on they will power them and when not the inverter will.

 

[jester]

So it may be that the simplest approach would be setting up the solar independent of the existing 110v system, and running a power strip from the inverter to power the 1 or 2 items you prioritize. For example, expecting to power the AC unit probably isn't going to work out from a solar/inverter. That's in addition to any 12v items you have/upgrade/add. The more details you give, the more helpful the input you'll get...

I did just this.  So much simpler and I only plan to use it to recharge phone/computer/etc.  No microwave, no AC, no tv.

 

[VegasVanGuy]

Thanks to everyone for the info. I think my electric needs are pretty light. A couple fans, cell phone, tablet for reading ebooks, laptop for the occasional movie. I do have a fridge/freezer that runs off either electric or LPG. It has an auto setting. I plan on snowbirding in the Western US so AC/Heat won't be much of an issue. I am going to add the inverter separate from the existing 110v system just to keep things simple. I'll start another thread on the solar build because I'll have more questions and want more recommendations.

 

[highdesertranger]

sounds like a good plan. highdesertranger

 

[ccbreder]

How many items on 120V = how large K watts inverter = how many amp hour battery bank = How to charge depleted battery = how many solar panels.

 

[ZoNiE]

I'm not very familiar with RV systems but I'm of the KISS cult. I was helping a friend with his generator and asked where the transfer switch for toggling between shore power and the generator was. His answer was "You just change the cords out" and showed me inside the generator area was a male 30amp receptacle that fed the panel. If on shore power the female end of the cord was plugged in and if on the generator it was swapped for a cord from the generator. You can't get any simpler than that and if on an inverter just plug in that cord. Of course it would involve a minute or so of time to swap plugs. This system would allow inverter power to everything on the AC panel so the operator would be required to exercise some common sense as to what loads would be appropriate to run. A receptacle and three cord ends would certainly be simple and cheap while some kind of automatic switch would be more expensive and complicated to install.

You can always add the switch later if you desire.

Guy

My GMC motor home was setup that way and I thought it was crude but it makes sense and gives you a place to store the plug. I set up my travel trailer this way when I added a genset.

 

[blars]

Inverters are not standard on older or lower-end RVs. If you do put the inverter powering the existing wiring, make sure to turn off the converter and put the tringe on propane-only unless you have lots of solar and batteries.