powering 24" LCD TV via V-mount battery?

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firehawk

Veteran
I'm trying to determine a way to power my 24" LCD TV or 22" monitor via V-mount battery (not both from same battery). I've been looking at some V-mount to AC adapters. If the TV is rated at 40 watts, how long would it run on a 95wh battery?
Do you have any suggestions on how to accomplish this?
 
It depends on how efficient the adapter is and how accurate the 40w and 95wh specs are, but if those numbers are good, about 2 hours.
 
Are your monitors truly AC powered, or do they have power supplies that plug into the outlet and then connect to the monitors? If the latter, check the label on the power spplies to see what the outputs are. They are definitely DC out and they may even be 12v. If so, then you can get a cable made that plug directly from the battery to the monitor. This circumventing of the transformer will save you about 20% efficieny in your use of power an will also be less expensive.
 
Good idea! Thank you.
One monitor just uses a straight standard AC 3 prong cord like computers and many devices use with no adpater but...
the other monitor uses an adapter cord that says "switching power supply. Input 100-240V ~50/60Hz 1.0A. Output 12V 2.5A" wall AC plug on one end and DV barrel tip on the other
 
The second one will run at least 2 hours on a 95WH battery. The label on the adapter says that it is rated 30W (12V x 2.5A = 30W). The monitor should be using less than that as the adapters are normally overrated, so in fact you might get over 3 hours.
 
firehawk said:
Good idea! Thank you.
One monitor just uses a straight standard AC 3 prong cord like computers and many devices use with no adpater but...
the other monitor uses an adapter cord that says "switching power supply. Input 100-240V ~50/60Hz 1.0A. Output 12V 2.5A" wall AC plug on one end and DV barrel tip on the other
Click to expand...

Bingo, so you only need to make a P-Tap to DC barrel connector cable. I would suggest getting a regulated cable like the ones several camera accessory makers offer so that even if the battery is kicking out a higher voltage you still feed 12v to the monitor. It's possible that the monitor uses the same connector as a camera -- you need to check what size it is. nd lastly you need to confirm which part is the positive lead and which is the ground so that you don't send reverse polarity into the monitor. The easiest way to do that is to stick a voltmeter onto the 12v out connector on your current power supply and see what it gives you. The power supply should also have a simple diagram on it, but it can't hurt to physically check.
 
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