400 watt inverter in Entertainment Center

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Feb 9, 2006
I recently installed a 400 watt inverter (cigarette lighter plugin) into my entertainment center to run my TV and DVD player at night without using my generator.  The TV and DVD player power up fine with AC power or generator on, but will not power up the TV or DVD without it.  So I have had to turn my inverter on, power up my TV and DVD, and then shut my generator down. It works fine all evening and only uses 1/4 of my battery power.  Will a 500 watt inverter correct this problem? Or do I need to check something else ???


Moderator Emeritus
Mar 3, 2005
Elkhart Lake, WI for the summer. Work at Road Amer
Almost sounds like the inverter is shutting down because the input voltage is too low; 10.5 volts or so, and with the genset running, the input is up to 12.6 or beyond. Maybe the starting load from your tv/dvd is too much (drawing the voltage down too low), but without knowing brand/model t.v., etc. it's only a guess. Measure your input voltage with a vom. Try plugging a 250W heat lamp all by itself into the inverter and see what happens, then post back with results and details of your setup. 


Jan 13, 2005
Did you use a long 12V extension cord? If so, this could result in the problem that Karl mentioned. Either use larger wires between the battery and the inverter, or locate the inverter closer to the battery and use an AC extensionn cord from the inverter to the entertainment center.

Gary RV_Wizard

Site Team
Feb 2, 2005
At our Silver Springs FL home
A Karl has said, the problem is almost surely that the initial power draw from turning on the tv is large enough to overload the inverter.  It's possible a larger inverter will help, but I am more inclined to think it is a 12V input problem.  When the tv/dvd powers on, the initial surge causes the inverter to suck a lot of amps from the battery and the input voltage drops. That in turn causes the output (AC) voltage drop and the tv desn't complete its power on cycle.  The inverter might even shut itself off if the input voltage drops low enough (typically around 11 VDC).

There are a couple of likely causes for this problem. First of all, standard cigaraette lighter outlets are often underpowered, with wiring that is too small a diameter and too long a distance to the batteries. This can be correced by running a large gauge wire (12 gauge will handle the max that a lighter plug can deliver) as direct as possible to the batery itself or the 12V distribution (fuse) panel.)  The other likely cause is poor batteries or a corroded connection to the batteries. The initial battery voltage may be low or their condition may be poor enough that they cannot sustain their voltage when any load is applied. [Batteries sometimes show a good voltage at rest but "die" under any sort of load]. 

How old are the batteries? Have you checked the water in the cells lately?  With your genset and shore power off, put some 12V lights on in the rig for 40 minutes or so, then check the DC voltage at the lighter plug or fuse panel. If less than about 12.5 volts, I'd say your batteries are in poor condition.


Well-known member
Mar 9, 2005
West Melbourne, FL
I just installed a Xantrex RS400 400Watt sine-wave inverter and found the same problems. It was definitely the 12Volt wiring. I tried everything that I could think of with no positive results until.? My MH has a 3/0 cable running from the battery to the front of the body. I mounted the inverter on top of the diesel generator(which is located in the front) and connected to the big 3/0 cable with #6 wire. I used a marine cutoff switch and a 60Amp fuse. I run the 120V from the inverter to the entertainment 120V supply line. It seems to work fine now.


John From Detroit

Well-known member
Apr 12, 2005
Davison Michigan
Somewhere in the owner's manual for your 400 Watt inverter it should mention that cigg-lighter plugs are suggested only for under 200 watt loads.  (many are fused at 10 amps, tha'ts 120 watts)  You need to hard wire it to the load center with heavy guage wire for best results,  as someone else suggested

I tried an older 400 watt inverter and it would not take the load, A new one would have... this was age of hardware issue though, ti's wore out.

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