YES another Invertor Question

[Shadowman]

I've spent hours reading about inverters from all of you, and seems like there is a wealth of knowledge and an endless number of issues related to each persons desires. I'm hoping I can explain my circumstances and see if its possible.

What I would Like to do:
In the front of our Class A we have the overhead which houses a TV (120)and an older VCR (12V). I've recently upgraded the TV so we have jacks in the front to plug in a DVD player when we stop. What I would like to do is remove the older VCR (12V) and replace it with a modern DVD player, and in the same area (overhead) install a 400 Watt inverter to power the TV and DVD to avoid running the generator late at night and annoying people.

So my question is this: Can I get a 400 watt inverter that will plug into the 12V plug used for the current VCR (which is in the overhead) and plug the TV and new DVD into the inverter.  I'm trying to avoid running wire to the battery with it being in the overhead, it would be a challenge to run and hide it.  The second question is, by having the inverter in the cabinet in the overhead, will that cause it to overheat, do these things need some sort of cooling space?  I'm willing to try anything, but I'm one of those people that if my power goes out, the DVD is blinking 12:00 for the next year and a half. 

Thanks for all the advice, you all have saved me great pain with all the advice.

 

[Ned]

A 400W inverter will draw over 35A at full load so check the fuse for that outlet and be sure it's large enough.  I would suspect it's probably 20A, not large enough for a 400W load but will handle a 200W load.  If not, you will have to run new wires from the battery to power the inverter.  This circuit will also need to be fused appropriately.  There will be heat generated but whether you need additional cooling will depend on the installation.  We leave the cabinet doors open on our satellite receiver and home theater when in use to allow for air to circulate, but if it's a tight fit, you may need to add a fan to aid in cooling.

Check the actual power requirements of the RV and DVD player and see what size inverter you really need.  400W seems like a lot for just those 2 devices.

 

[Gary RV_Wizard]

I agree with Ned - the existing outlet will be nowhere near enough for a 400W inverter. You might get by with a smaller one, maybe 250-300W, but it would be best to run new 12V power to the overhead in any case.  A 20A outlet (if it is even that big?) would provide at most 240-250 watts of power and power loss do to inefficiency would make it a bit less, mabe 200-220.

 

[Shadowman]

Gentlemen, thanks as always.

What would I look for on the TV to tell how many watts I will need. I looked on the TV's sticker on the back and it only talks about 6.5 amps. Could that be converted to watts?  Sorry for the ignorance, but this is really out of my area of expertise, but I'm learning.

What to look for????

Thanks,

 

[woodartist]

The 6.5 amps is for the 120 vac? In general, without getting into complex math., the power = Voltage times the current. or, P=EI. AC is different than DC, but to keep things simple the equation will be in the ball park. So, P=120 X 6.5=780 watts. Actually it is less, but again it gives you a rough idea. You can solve the equation for other variables......

 

[Ned]

6.5A at 120VAC seems too high for just a television.  Our 23" LCD TV draws 110W or about 1A at 120VAC in operation.  6.5A would be about right for a small 12V television, however, and that would be 78W.

 

[Gary RV_Wizard]

Yeah, Ned it right on.  6.5A is far too much for a 120V TV, unless it is an old vacuum tube model!  I would guess it would be in the range of 2.0-3.0 amps or 240-360 watts.  But if it is a small 12V tv, then 6.5A is about right.

An LCD tv like Ned's draws hardly any power and any tv with a CRT will draw somewhat more, but not anywhere near 6.5A.

 

[John From Detroit]

Gentlemen, thanks as always.

What would I look for on the TV to tell how many watts I will need. I looked on the TV's sticker on the back and it only talks about 6.5 amps. Could that be converted to watts?  Sorry for the ignorance, but this is really out of my area of expertise, but I'm learning.

What to look for????

Thanks,

6.5 amps is 780 watts, A tube type color televison of reasonable size is about 300 watts.  That must be the start up current on the de-guass coil (They can draw some serious current when they first kick in) Others have given more reasonable figures

 

[Karl]

Shadowman,

The label indicates the average current consumption at the stated voltage. Unless you have a really ancient t.v. set, I'm guessing it's rated for 6.5 amperes at 12 volts, or 78 watts. That amperage at 120 volts (6.5 X 120= 780) sounds about right for a 1960's RCA 21" color t.v, and I'm guessing that's not what you have!

The 12 volt power you have now is probably 15 or 20 amperes maximum (180-240 watts). Check your fuse panel. You should be able to power an inverter in the range of 200 watts without any problem, and that should be adequate for a 17-19" t.v. and dvd player. As was said before (and I paraphrase) when it comes to wire and fuse sizes, bigger is better. If you have any doubts about your present wiring being able to handle the power draw, pull some new wire (not always easy) and increase the fuse size. DON'T just replace the fuse with a larger size - you run the risk of an electrical fire!   

 

[woodartist]

My advice would be to get it done right and go to a professional. It isn't worth burning up the equipment..or worse the rig. That way you can have someone actually see the set up, and maybe even give you some free advice. When it comes to electronics and power, it isn't worth the risk. In one of my previous lives I made some decent money correcting the errors FYI