How long will a 12V battery power a 60in TV?

DuffMan · November 8, 2015

Need to operate a 60 inch lcd TV in a remote location w/o power - The TV draws 150 Watts at 120 Volts.

I want to make up a battery box with a 12 V AGM auto battery with a 12 V to 120 V inverter mounted on top.

Can I get 10 hrs of operation of the TV off that battery setup? (Any idea on approximately how long it will actually operate?) Trying to find the Amp Hr rating of various batteries has been a challenge.

oldjohnt · November 8, 2015

Lets do the math

150 watts @ 120 volts means the TV draws 150/120 = 1.25 amps @ 120 volts

1.25 amps at 120 volts fed from an inverter means you will draw "APPROXIMATELY" 12.5 amps from your battery when the TV is running. (ONLY an approximation the answer depends on inverter and its efficiency and exact voltages)

Okay THE ANSWER DEPENDS ON HOW MANY AMP HOURS OF ENERGY YOUR BATTERY CAN SUPPLY

If you had say a 12 volt battery rated at 100 Amp Hours (NOT a cheap battery mind you) and lets say you wouldn't want to draw it down over 50% max that means you could use it to supply 50 Amp Hours of energy.

At 12.5 amps for FOUR HOURS of operation that's 50 Amp hours before TV use would have drawn 1/2 of the batterys (100 AH rated) stored energy

If you want to run the TV 10 HOURS and its drawing 12.5 amps from your battery that's 125 Amp Hours and if you dont want to expend over 1/2 battery energy storage capacity you would need 250 AMP HOURS OF ENERGY STORAGE.

BEFORE ANYONE HAS A CALF 1) These are ONLY rough short easy answer approximations, if I had all the exact specs, I could provide an accurate answer. 2) I don't advise drawing a battery down over 30% and dont advise drawing them down to 50%. 3) I would take a look at true deep cycle 6 volt golf cart type of batteries in series versus automotive or semi deep cycle so called RV/Marine Batteries.

Given the TV draws approximately 12.5 amps of DC from your batteries, its now an easy calculation to see how many amp hours of energy storage is required to run the TV for X amount of hours and again I would not draw the batteries down anywhere near 50% of their capacity (20 to 30 is my preference)

John T

DavidMc · November 8, 2015

John T has done the essential math.

You need at least a pair ( two six-volt batteries to make 12 volts ) of something at least this big: http://www.interstatebatteries.com/p/golf-car/5-0-7-0-volts/interstate-batteries-u2200-gc2-xhd-utl?dsNav=N~2147384911-2147384722-2147384903

Is this a one-time instance that you need this ?

OR . . . will you be doing this many times ?

( In my opinion, you could squeak by on the above if it is just for one time ; otherwise invest in something more robust. )

Jim Gell · November 8, 2015

Without having looked at any consumption ratings, it MAY be more economical to purchase a more efficient LED TV to replace the LCD TV than buying higher capacity batteries. If it were me, I would look into that option before I spent a lot on batteries.

Jim

On Edit: I retract my suggestion. After looking at 60 inch TV specs, it appears you not going to find one that uses much less than 150 watts.

oldjohnt · November 8, 2015

PS The battery David Mc posted is rated at 232 Amp Hrs, so two of those in series could supply 8 hours of TV viewing at 12.5 amps (100 Amp Hrs.), which is a reasonable draw down discharge of a 232 Amp Hr rated battery bank, so you could watch that TV for 8 hours if you had two of those batteries in series (or more if you don't mind exceeding 100 Amp Hrs which is nearly half their rating)???????????? I have four six volt 230 Amp Hr rated batteries in series/parallel which gives me 460 Amp Hrs of energy storage and that more then meets my modest energy needs as I have 400 watts of solar to recharge the next morning. Some gents here who require more energy may have 600 or 800 or 1000 plus solar watts and 6 or 8 or even more batteries, so if you choose two you're certainly not out of line.

John T

DuffMan · November 9, 2015

Thanks guys. Looks like a couple 6V Golf Cart Batteries will be required. Have to rig up on a dolly for easy transport.

Tom_M · November 13, 2015

Is the 150 watts an actual measured reading or what is printed on the label on the TV?. If it's from the label, that would be the maximum rating. My TV uses much less power then what is specified.

mohamer · November 18, 2015

You might look for a TV that runs off of 12 volts, that way you don't have the loss of an inverter to deal with.

Also check the voltage specs on the inverter, the battery may not be able to provide the current and voltage for as long as you need.

oldjohnt · November 19, 2015

My TV uses much less power then what is specified.

Tom M, good point, the only way to measure actual consumption is an ammeter of one of those KW meters. Its true the actual draw may be less.

John T

skp51443 · November 19, 2015

For around $20 I don't know how anyone can resist having one of the Kill-A-Watt meters, they are very neat little tools. They have fancier ones that do more for not too much more but the 4400 will do the job.

http://smile.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_1

If you are looking at an LED illuminated LCD the power draw can vary with total screen illumination so a snow covered scene will use more power than a dark night scene so check a couple different channels to get a variety of test scenes. The power will also vary with your TV settings, the brighter the screen the more power is going to be used.