TV Amp Hours

[woodlodge]

How many amp hours would a TV use running strictly on battery on an overnight stay without hookups? Can I expect the batteries to carry this with a few lights also, or would I need to run the generator? I'm talking about pulling into a Wal-Mart in the evening and leaving next morning.

[wolfe10]

First, you need to determine how many amp-hrs of battery you have available. Are the batteries fully charged? Are they reasonably new or old with diminished capacity? For best battery life, do not discharge batteries below 50%. All together, this should give you an idea of how many amp-hrs you have available.

Next, you need to determine total load on the batteries. There are lots of other 12 VDC loads than just the TV: lights, refrigerator (even on propane), water pump, furnace, etc. And while you can determine the amp draw of the TV, if a 120 VAC TV, remember the draw from the inverter to run that load is not 100% efficient. A reasonable calculation for a 120 VAC appliance is to determine its power consumption in watts. As an example, let's say 3 amps/360 watts. Watts divided by 12 VDC gives you the amps of 12 VDC (assuming 100% inverter efficiency). So in our example 360 divided by 12= 30 amps @ 12 VDC. Figure 90% inverter efficiency to give you the final amp draw on your batteries. So, in our example, your batteries would provide 33 amps while powering the TV.

Brett

[pkendzor]

Brett is right on the money. If you don't know the AH capacity because of the age and you are not sure of your TV wattage or furnace fan draw you can always try this.

One day when you are parked without the engine or generator running even out shopping leave the TV on for an hour or two. When you come back check your battery indicator panel and see if you are still in the green.

On a cold night with the propane heat on we watch 2 or 3 hours of TV with the inverter with no problem. We have two 12V batteries about 2 years old.

I dont remember the Amp Hours.

Paul