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BJCSF2014 · 01-18-2016, 04:03 PM

I think this must have been asked before and seems so basic, yet I haven't been able to find the answer anywhere.

I bought a small inverter from Costco to watch TV and charge mobile devices with for the rare times I'm not hooked up to shore power. It worked great this weekend except I had to jump start the RV 24 hours later. Very simply, I wrongly assumed that I was drawing power from the coach batteries instead of the chassis battery and monitored my "AUX" voltage and ignored my "MAIN" voltage.

If I don't use the inverter, I need to run the generator in order to have power to the 120 outlets and thus watch TV. If I use the inverter, I would have to start the engine to charge the chassis battery each morning. It's not the worst thing in the world but I get the feeling there is something simple I'm missing whether it's a step or a part. Newbie question?

vsheetz · 01-18-2016, 04:51 PM

Sounds like, if I am following correctly, you have the inverter connected to the chassis/engine battery. The inverter should be connected to the house batteries.

BJCSF2014 · 01-18-2016, 04:57 PM

Quote:

Originally Posted by vsheetz

Sounds like, if I am following correctly, you have the inverter connected to the chassis/engine battery. The inverter should be connected to the house batteries.

That's a huge clue. I bought a cheap inverter that plugs in one of the 12V cigarette lighter type plugs. I guess that should have tipped me off that it would be from the chassis battery.

Mr_D · 01-18-2016, 05:10 PM

Quote:

Originally Posted by BJCSF2014

Is there such a thing as a single dedicated connection to all the 120 outlets in the RV?

Yes, not cheap though. A PSW with a charger and inverter combo plus install and wiring could go into $3,000 or more.

twinboat · 01-18-2016, 05:26 PM

Quote:

Originally Posted by BJCSF2014

That's a huge clue. I bought a cheap inverter that plugs in one of the 12V cigarette lighter type plugs. I guess that should have tipped me off that it would be from the chassis battery.

Check for other lighter plugs. I have a few that run off the house batteries.

BJCSF2014 · 01-18-2016, 05:39 PM

Quote:

Originally Posted by twinboat

Check for other lighter plugs. I have a few that run off the house batteries.

I do have other plugs. One near the passenger seat, one where the bedroom TV would go and one under the counter in the bedroom. This sounds very promising. We mostly watch TV in the front so I never installed a TV in the bedroom (we bought used and it came without). Hopefully the one by the passenger seat is the ticket.

TQ60 · 01-18-2016, 07:10 PM

Check for voltage in plug with battery off.

If dead then turn battery on to confirm.

Verify engine battery is off via no start condition when power present at plug.

However...Most plugs have small wire as they no longer are for cig lighters so the ability to operate an inverter us not usually there.

The plugs are lesser sized and quality so inverter current for constant time can melt the plug.

Locate a power buss and wire inverter to that bus with a switch and fuse.

Also consider a tv that uses a wall wart or adaptor that outputs 12 VDC as those can run directly off the battery and can be plugged into the cig lighter with an adaptor cord.

twinboat · 01-18-2016, 08:13 PM

A 20 inch flat screen may draw 75 watts.

That's only 6 amps @ 12 volts. Add 10% for the inverter and it's still less then 7 amps.

The cigar lighter plugs can easily handle that without melting.

Buying a new TV that can be modified for 12 volt use only eliminates the small losses thru the inverter.

I think you will be fine, doing what your doing, as long as you find a cigar plug hooked to the house batteries.

vsheetz · 01-18-2016, 09:33 PM

Yes, you likely have other 12vdc power outlets that are off the house batteries. The one(s) in the dash are likely off the chassis battery. If none are close enough to the TV maybe an extension cable can be utilized. Or some rewiring to get one where it's needed.

BJCSF2014 · 01-19-2016, 10:02 AM

Thanks for the info everyone. I have a greater understanding of RV electrical now. Since I have a 12v outlet where the bedroom TV goes, I'm assuming there is one behind my front TV as well. Thanks again.