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Author Topic: small inverter wiring  (Read 201 times)

japanders

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small inverter wiring
« on: May 04, 2019, 01:00:44 PM »
Hi all! I've looked around and can't find a thread on this topic. I've got a new battery to put in the trailer next week and would like to get a small (400-600W) inverter to run a few odds and ends. I'm not sure what's the best way to wire it up.

One thing I wondered about was hooking it up to the panel where the 12V comes in. Our panel is in the kitchen, which is where we want the inverter outlet available. Is there some kind of bus bar on the back of the panel that I could attach to? Or will it be best to hook up directly to the battery?

It's a travel trailer with the battery outside on the A-frame, so there's not really a spot near the battery to mount an inverter like there would be in a fifth wheel.

Thanks in advance!
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Isaac-1

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Re: small inverter wiring
« Reply #1 on: May 04, 2019, 01:52:44 PM »
You need large wire to power an inverter, anything bigger than 75-100 watts will likely need dedicated large wiring to the battery, a 400-600 watt inverter will likely need wiring in the same size range was runs from your starting battery to your engine.
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Gary RV_Wizard

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Re: small inverter wiring
« Reply #2 on: May 04, 2019, 03:44:27 PM »
Locate the inverter as close to the battery as possible, to shorten the cable to the battery. That allows a smaller cable and less power loss. Then run a 120v extension cord to the places you need power.
Gary
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Lou Schneider

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Re: small inverter wiring
« Reply #3 on: May 04, 2019, 05:24:53 PM »
12 volt wiring is 100 times more sensitive to voltage loss than 120 volt wiring, so use 12 volt wires that are as large and as short as practical.  You want to locate the inverter as close to the battery a you can but not in the same compartment due to battery gasses.  Then extend the 120 volts to where you need it.

The power panel in the kitchen may or may not work, depending on the size and length of the wires between it and the batteries.  600 watts is about 50 amps on the 12 volt size, so you'll need wiring capable of handling that much current (#8 or better) and not lose significant voltage along it's length.

If you put the inverter some distance from the batteries, i.e. in the kitchen, the voltage loss along those long 12 volt wires can make the inverter shut down from low voltage when you put a load on it, even if there's plenty of charge in the batteries.
« Last Edit: May 04, 2019, 05:35:08 PM by Lou Schneider »

John From Detroit

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Re: small inverter wiring
« Reply #4 on: May 04, 2019, 05:34:05 PM »
The brest place for an inverter is a compartment NEXT to where ther batteries hide. NOT in the damer 'Air space" but next to it.. That way you need only a short heavy cable (For a small. say 400 watt you can likely get by with starter cable up to around 3 feet) THen run 120 volt wire to where you want to ue the power.. IN YOUR CASE if it's not too hard to move plugs I would suggest you simply add outlets.. A different design or color (Orange works for me or surface mount) to "Set them off" from the Regular "Shore power" wiring..

For bigger (1KW or larger) a sub panel (2nd breaker box) and a transfer switch (often built into the inverter) is better.
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japanders

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Re: small inverter wiring
« Reply #5 on: May 04, 2019, 07:20:45 PM »
Sounds like I just need to find a way to get a short run from the trailer tongue to my storage compartment for the inverter and then pull 120v wire inside. I can manage that.

Any recommendations on type of inverter, brand, features, etc? Weíve got a 105AH battery and donít plan to run anything heavy like a coffee maker or instant pot or anything like that. Iím thinking about 400-600 would be plenty. Not sure if I need pure sine or not.

I may look into a bigger system in the future, but Iíd like to do something simple so I can learn and do it myself. We canít fit more or bigger batteries on this trailer right now.
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Gizmo100

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Re: small inverter wiring
« Reply #6 on: May 04, 2019, 08:00:40 PM »
I mounted my inverter in the pass though storage area. ran the cables to the batteries though the floor. I connected a 100 amp cutoff/ breaker. I believe ours is 1000 watts.

As far as using it.........

I shut off all the 120 volt breakers. Then I use a adapter to plug my RV plug (30 Amp) into the inverter. I then turn on the Main breaker and one other breaker that power the TV outlets and the bedroom outlets. It will also power the refrigerator but I keep it on gas to conserve the power from the batteries.

NOTE...
If you choose this method it's important to make sure you shut off the breaker to the converter. It will kill your battery. The other breakers are to make sure my wife doesn't try to turn them on and kill the batteries or blow a fuse.
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Gary RV_Wizard

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Re: small inverter wiring
« Reply #7 on: May 05, 2019, 07:12:01 AM »
Quote
Any recommendations on type of inverter, brand, features, etc?
Modern tech has made inverters a commodity, so you can pretty much choose based on price.  I'd probably avoid the cheapest models simply on suspicion they may have cut too many corners on it, but no need to go for the higher priced traditional top brands (like Xantrex and Magnum) either. 

Pure sine doesn't cost all that much more nowadays, so that would be my choice.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL