Need Help about Battery Pack Setup

[BretMan]

Hello Everyone,
I recently bought for hurricane emergency use here in Miami, a 7" LCD portable TV. It comes with a home power connection and 12v DC IN via a male plug for female vehicle cigarette lighter sockets. The internal battery is a Lithium Polymer 1800mAh which after we tested it, it lasted about 2 hrs.

To extend the watching time of the TV I want to have the option of plugging it into a battery pack. This needs to be simple so my elderly dad can use it so I'm thinking an easy way is of a pack that holds a set of D size batteries, connected to a 12v socket. So I have these questions since I'm an electrical novice:

1- What do I need to set a pack like that up? Is it just a matter of getting a battery holder and inserting 12 D batteries in it?
2- How long will 12 batteries last and is there a formula to calculate this?
3- If I go with a pack with more batteries, how do I make the connections to have 12v or does it not matter?
4- I also though about getting computer backup power box like those from APC and plugging in this AC/DC adapter:

http://www.meritline.com/car-charge...&hq_e=el&hq_m=1985142&hq_l=88&hq_v=c61b927e65

Will this work and if so how do I calculate how long one of those will last to power just this TV? I wonder if the rechargeability of it will make it more economical in the long run.

Thank you.

Bret

Miami,FL USA

 

[VEBill]

Purchase one of those inexpensive rechargeable portable lead-acid 12 power packs. They're typically about $30-40. They often have built-in booster cables, and cigarette lighter sockets.

A larger unit should outlast 8 (not 12) D-cells.

 

[BretMan]

Thanks for the suggestion. I searched for them but I'm not sure which you mean:

http://www.thinkawesome.com/200w-rechargeable-batteries.htm

http://www.zbattery.com/B-B-12V-7-5...9d3daa580b2bb53b.e3eSchmSbxaRe34Pa38Ta38Lbxj0

If it's the black one with the 2 flat terminals, is all I need to do is to connect a female socket with a couple wires to it? How do I recharge it - trickle charger like for a car battery? How do I calculate how long it will last before buying?

Bret

Miami,FL USA

 

[DRWeig]

Not quite, Bret ---

I think VE1BLL was referring to self-contained 12 VDC power sources. Stick the following term into Google:

Duralast jump starter

There are all sorts of capacities, other brands, etc... This is something you keep charged up from your house electricity, then it'll provide 12V for your TV via the automotive 12V lighter socket.

Good on ya,

Goober Dave

 

[BretMan]

Thanks Goober Dave,
Well, I'm not finding the Duralast one but there are others I saw around $70 +. All depends on the power and that's what I'm still stick on. How do I calculate how long it will last?

The Battery in the TV w/ 1800 mAh I'm guessing = 1.8 Amps which lasted 2 hrs. So if I divide the 1800 by 900, I get 2 or 2hrs, so that works out right. A sample "Duralast" says it's 200 Watt & 400 Amp. So 400 = 400,000 mAh /900 = 444 hrs. the TV can run on it - that's doesn't look right at all - or is it?

Bret

Miami,FL USA

 

[IRstuff]

I think you're misreading the specification. The 400 A is most likely the cold cranking amperage (CCA), which is it's rated starting current for a car starter motor. It cannot sustain that level for more than a few minutes. The 200 is mostly likely the "reserve capacity" which is the discharge time for a 25 A load and represents 200 minutes. Which should imply that the battery will last about 5000 minutes at your load, or about 80 hours.

TTFN

FAQ731-376

 

[VEBill]

They're normally available at stores like "Mall*Wart" and Costco. $80 should be a huge, top of the line version, if the pricing is fair.