Replacing DC TV with AC TV

[scotta]

I have disconnected the dc jack connected those wires to a 400 w 2 socket inverter in the bedroom. The inverter reads 12 volts in , o power out and 115 volts power. When I plug in the TV the inverter shuts off. What do think Ithe problem is? ANy help is much appreciated.

[jdalrymple]

Several ideas..

Does the TV draw more than 400 watts?

Wiring in the wall from the removed 12 volt receptacle may be insufficient to supply the inverter.

I would research the TV’s power requirements and it is rated under 400 watts, I would connect the inverter directly to a the battery and see what happens.

Best of luck,

[Jim Foster]

It sounds like your inverter is overloaded. Either the TV draws more than the inverter can supply, or the 12v wiring to the inverter is not sufficient, or both. The wiring to a 12v cigarette plug is usually 12 or 14 guage, 10 gauge at the most. None of this is heavy enough for a 12v DC to 120v AC inverter.

When I wired my inverter, I went to a parts house and got a cheap set of jumper cables, cut off the clips, added good connectors and went straight from the batteries to the inverter. It loves it.

[bibbs]

your 12 volt feed wires are too small 400 watts at 12 volts needs at least

#8 wire. I found out the same thing when I hooked up my 1000w espresso

maker,I had a 2000 watt inverter I needed to run 1/0.

12 volts @400 watts=33.3 amps round up to 40amps=#8wire size For a short

distance to the battery

bibbs

[scotta]

Originally Posted by jdalrymple

Several ideas..

Does the TV draw more than 400 watts?

Wiring in the wall from the removed 12 volt receptacle may be insufficient to supply the inverter.

I would research the TV’s power requirements and it is rated under 400 watts, I would connect the inverter directly to a the battery and see what happens.

Best of luck,

TV draws 80 watts. How do run a heavier wire all the way to the battery as others have suggested?

[scotta]

Originally Posted by bibbs

your 12 volt feed wires are too small 400 watts at 12 volts needs at least

#8 wire. I found out the same thing when I hooked up my 1000w espresso

maker,I had a 2000 watt inverter I needed to run 1/0.

12 volts @400 watts=33.3 amps round up to 40amps=#8wire size For a short

distance to the battery

bibbs

If the TV only draws 80 watts; would I be better off with a smaller inverter, say 150 watts? Would the existing wiring operate the inverter or would I still need to run larger gauge wire all the way to the battery? I could order another TV that is AC/DC but they cost much more than the straight AC TV I bought on sale over the holidays. I have no idea on how to run wire to the battery.

[bryanl]

The 400 watt inverter should do just fine and might be more efficient at 80 watts than a smaller one.

If voltage drop to the inverter is the problem, you can check by temporarily connecting the inverter directly to the battery and then plug in the TV or a similar load. If that works then you should connect a 12v load of about 7 amps to your 12v source in the bedroom and see what kind of voltage drop you have. 7 amps is like a couple of lighting fixtures using the 1183 incandescent 12v bulbs or an auto headlight.

If you can get 7 or 8 amps out of the bedroom 12v source without dropping below 11.5 v you should be OK - check the inverter manual for its low battery cutoff voltage. That is usually 10.5v or so.

If you are suffering voltage drops on the 12v line in the bedroom and AC/DC tv isn't really going to help. That drop represents a power loss that will happen either way. A 1v drop on an 80 watt load is going to represent almost 7 watts power loss. This is why it is always better to have the inverter close to the battery and run 110v lines to the load as that 80 watt load will then represent only 3/4 of an amp rather than 7 amps and the power loss is related to the square of the current.

It is also worth noting that a DVD movie is an easy way to run a battery down. Most TV's, even LCD's, will use more than 100 watts and a solid 10 amp drain on a battery runs them down in a hurry.

[scotta]

Originally Posted by Leipper

The 400 watt inverter should do just fine and might be more efficient at 80 watts than a smaller one.

If voltage drop to the inverter is the problem, you can check by temporarily connecting the inverter directly to the battery and then plug in the TV or a similar load. If that works then you should connect a 12v load of about 7 amps to your 12v source in the bedroom and see what kind of voltage drop you have. 7 amps is like a couple of lighting fixtures using the 1183 incandescent 12v bulbs or an auto headlight.

If you can get 7 or 8 amps out of the bedroom 12v source without dropping below 11.5 v you should be OK - check the inverter manual for its low battery cutoff voltage. That is usually 10.5v or so.

If you are suffering voltage drops on the 12v line in the bedroom and AC/DC tv isn't really going to help. That drop represents a power loss that will happen either way. A 1v drop on an 80 watt load is going to represent almost 7 watts power loss. This is why it is always better to have the inverter close to the battery and run 110v lines to the load as that 80 watt load will then represent only 3/4 of an amp rather than 7 amps and the power loss is related to the square of the current.

It is also worth noting that a DVD movie is an easy way to run a battery down. Most TV's, even LCD's, will use more than 100 watts and a solid 10 amp drain on a battery runs them down in a hurry.

The lights in the bedroom are connected to the same switch as the power to the TV. So I am trying to power the TV and the overhead fluorescent light as well as the two reading lights on either side of the headboard. In reading your post it makes me think this may be the problem. I am really ignorant when it comes to electricity or any mechanical stuff. I admire people like you who have those skills. I do know contract Law if I can ever help you though :-)