Community Forums

GVJeeper · 08-31-2015, 10:12 AM

My only 12-volt socket in my TT is in the front which is the bedroom and near the house batteries. My entertainment center is over 30 feet away in the back. I want to plug an inverter into the socket for the TV, DVR,

etc. 30 feet away. How long of an extension cord (with a power strip on the end) can I run? I'm looking at a BESTEK® 2 AC Outlets 1000W Power Inverter on Amazon.

Gary RVRoamer · 08-31-2015, 10:44 AM

Plug the inverter into the nearest possible 12v source and keep the 12v cord short (and use a fat one). The extension from the inverter to the 120v units can be as long as you like. At the loads you are talking about, the power loss on the 120v side is negligible up to maybe 50 ft.

Be aware that the 12v socket probably cannot provide anywhere the power (amps) the inverter might demand. A 1000W inverter at full load needs about 90 amps from the batteries, and a typical 12 plug-in outlet can handle maybe 10-12 amps. Often they are fused for 10A. That enough for the inverter to power one device with about 100w power requirement, e.g. a modest sized tv. You will probably want to hard wire the inverter to the battery(s) with a heavy gauge battery cable.

Also be aware that the single small battery typical of many TT's is going to come up short trying to supply a large inverter. When the inverter sucks a lot of amps, the battery voltage soon falls and the inverter shuts down.

Dutch Star Don · 08-31-2015, 12:07 PM

If you want to do it right, skip the socket, they're wiring is usually very light weight and will either blow a fuse or cause other issues, especially running a 1000 watt inverter.

Instead, run one large #6 or #8 wire from your battery(s) to the rear of the coach along the frame rail and then bring it into the coach near your entertainment center. Run a short ground off of the frame near the back, giving you your two leads needed for the inverter.

tbbg II · 08-31-2015, 12:26 PM

Quote:

Originally Posted by Dutch Star Don

If you want to do it right, skip the socket, they're wiring is usually very light weight and will either blow a fuse or cause other issues, especially running a 1000 watt inverter.

Instead, run one large #6 or #8 wire from your battery(s) to the rear of the coach along the frame rail and then bring it into the coach near your entertainment center. Run a short ground off of the frame near the back, giving you your two leads needed for the inverter.

This is a bad idea (sorry, Don). It may work for the TV only, but the inveter can draw up to about 90 amps of DC. If you plugged in enough stuff to draw the 1000 watts it is capable of, you would need #1 or 1/0 wire to keep the voltage drop under 3% (to keep the wire from heating up). Some folks are comfortable with a 10% drop, but that would trip the inverter on voltage a lot quicker and the wire would get warm.

It may make more sense to wire the inverter to the batteries as close to the batteries as possible. Depending on the distance 6 gage would work (5 feet). I would never try to connect a device this big with a cigarette lighter connection. Then use a standard 120VAC extension cord. A 14g 50' cord would work.

Voltage drop is a function of amps and distance. 12VDC amps are some 10X the 120VAC amps for the same wattage.

twinboat · 08-31-2015, 12:31 PM

I just looked at some wire gauge charts. #6 or #8 will work for the TV stuff.

If your going to install a 1000 watt inverter and ever want to use it at full load, you should use #4 wire if close to the battery or #2 gauge wire if 10 or more feet away.

In any case putting the inverter close to the batteries and running the 120 volt power, long distances is best.

Dutch Star Don · 08-31-2015, 09:17 PM

"tbbgII"......I understand what you're saying, but did you read what he wanted to do. He was going to plug it into a cigarette lighter outlet. Those are wired with #16 or #18 wire. Yes, I would run a #1 or larger, but apparently he's buying some type of inverter that uses a cigarette plug. I don't know how they get 1000 watts out of a cigarette lighter.

I wasn't going to argue the value of what he was doing, just making a suggestion. I used 1/0 cable for 36" on my 600 watt inverter I ran for my residential refer.

vsheetz · 08-31-2015, 09:35 PM

Install the inverter near the batteries to keep the DC power run short. Use a smaller inverter, it will be more efficient. One with a remote on/off or auto power off sensing. Long AC run to the devices to be powered is ok. Power a switched power strip where all the devices are then plugged into it. This way you can stop phantom power draw.

Consider the Morningstar inverter.

IMHO.

GVJeeper · 08-31-2015, 10:56 PM

I think I'll go with a smaller inverter and wire it directly to the batteries (two 12-v) right there in the bedroom (only a couple feet to the batteries). Then use an extension cord to the entertainment center.

Thanks for all the answers (p.s. I'm a "she" and I drive a GMC 2500 pulling a 35ft Rockwood TT).

GVJeeper · 08-31-2015, 11:07 PM

I don't plan on loading it up...just run the wifi modem/router, 42" Visio smart TV, DirecTV DVR and my laptop. So what size inverter would you suggest and what wire gauge to the house batteries? If I go with a much smaller one can I still use the 12v cigarette lighter-type plug in the bedroom?

Again, I appreciate all your ideas and suggestions.

leeshearer · 09-01-2015, 06:09 AM

The best way to figure your power requirements is to look at the devices. They will tell you how much they draw. My 42" plasma tv at home draws 400 watts.

GVJeeper · 09-01-2015, 11:08 AM

My TV, DVR and wifi add up to just less than 200. My TV says 120v@1.3a so that's 156 watts...right? So...

if still use the 1000w inverter but only use 200watts, am I ok with the 12v socket do I still have to wire it directly to the batteries....safely?

I got the 1000w free so really don't want to buy a smaller one if I can still use it in my 12v socket....SAFELY.

twinboat · 09-01-2015, 11:55 AM

Set it up and try it. If the wiring is to small, you will get a low battery warning from the inverter as you turn things on.

Devide your watts by volts for amp draw.

You could also try other power outlets, that may be closer to the batteries if it warns of low voltage.

Gary RVRoamer · 09-01-2015, 09:30 PM

200 watts plus about 10% inverter power loss comes to 220 watts or about 18 amps from the batteries. I don't think any 12v "cigar lighter" socket is going to deliver that much, or at east not for very long. Or even have a fuse big enough for that much load. You need to hard wire. Or at least have good quality clip leads direct to the battery.

A typical 12v outlet is wired and fused for 10A. The better ones, e.g. the one in a Tesla, are 15A.

You can buy heavy duty 12v outlets rated for 20A, but you would have to wire it in yourself with a heavy gauge wire to the battery and a 20A fuse. Just as easy to hardwire the inverter itself unless you need for it to be portable.

GVJeeper · 09-02-2015, 10:32 AM

Thanks Gary. For me fire is a big issue so I'd want to be sure I wasn't overloading anything. I'll go for the hard wire.

I'm pretty handy but not sure what to do as the inverter has a 12v (cig-type) on it. How would I hard wire the inverter end? I can do the battery end but not sure how I would "replace" the 12v plug with a hard wired cable. Maybe I should just have someone do it for me.