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I have 2 EverReady 6 volt batteries model number 1209. I also have a 12 volt 1 amp screen that I need to power.

How can I power the screen with these batteries?

Wesley Lee
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user3536438
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  • The 1209 batteries aren't really rated for an amp current draw. Can be done for a short time. But that's pushing them. They'll drop immediately below the needed voltage. – jonk Sep 28 '16 at 04:57
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    Why do you expect some random stuff you have to work together? Just buy a car battery. – Dmitry Grigoryev Sep 28 '16 at 07:58

3 Answers3

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Unless your screen requires you to limit the current itself, it draw the amperage it needs, it's the volts you have to match yourself.

HilarieAK
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The obvious answer is that your hook them in series to give you 12 volts.

The more complicated answer has to deal with the question of the minimum voltage your screen will work at. This data sheet suggests that, if you need 10.5 volts or more, you simply will not be able to operate at all. If your screen is able to operate at 9 volts, it might last about 2 hours. So you need to find out the characteristics of your screen.

WhatRoughBeast
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  • i thought this would work pretty well at first... but i seem to not get any output or power directly from the series.... i think it needs 12 v dc exclusivly at 1 amp. – user3536438 Sep 28 '16 at 05:33
  • Right. The nominally 6 volt batteries will not put out 6 volts at 1 amp. Their actual voltage is too low to run the screen. – WhatRoughBeast Sep 28 '16 at 13:41
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You can use a boost regulator to get 12V from the 6.4-12V battery voltage (two batteries in series).

Many such regulators will drop very little voltage when the input voltage is similar to the desired output voltage. To get a reasonable fraction of the energy out of the batteries you need to keep the panel voltage near 12V even when the battery voltage has dropped to 800mV/cell (8 cells contained within two batteries).

I suggest you buy a module with a chip and other components already assembled, and capable of at least several Chinese amperes.

Chances are the panel actually draws less than the rated current, but this is still an expensive way to run an LCD panel.

Incidentally, contrary to your title, this will actually increase the current drawn from the batteries compared to the panel. Because, say, 0.8A at 12V is 9.6W and the batteries even nearing exhaustion at 6.5V must still supply 9.6W plus maybe 1-2W for the converter so the batteries will have to deliver 1.7A. Because of conservation of energy and thermodynamics and such like.

Spehro Pefhany
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  • interesting.... i thought voltage and capcacity was the issue.... not regulation..... How would you, (specifically because you seem to understand this pretty well), power the screen, from your experience and knowledge? if you know that the screen is built to run only on 1 amps and 12 volts dc input.... using specifically a portable meathod? – user3536438 Sep 28 '16 at 05:27
  • Rechargeable batteries, like those used in a laptop computer. For a one-off maybe an SLA (sealed lead-acid battery) if weight is not too much of an issue. With a regulator as suggested, and of course a charger. – Spehro Pefhany Sep 28 '16 at 05:31
  • I laughed at "Chinese amperes" – user253751 Sep 28 '16 at 21:50