battery power for fans
 

battery power for fans
i need to run different fans at room temperature for approx. 12 hours at a time and need them to be run by battery power (the smaller/lighter the better). can anyone advise me on what type of battery i need.
type of fans:
i)12v, 0.38a, 4.56w
ii) 12v, 1.1a, 13.2w
regards
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the lightest battery per watt-hour will be a nicad. i'm not sure about smallest size per watt-hour. they can be a nuisance, though,as anyone who hassome knows.
you will need to know the operating temperatures and duty cycle for these fans.
your power needs total 18 ah and although you haven't said this, in order to keep the battery small, it sounds like you'll run the fans till the battery is nearly flat. with this in mind i think you'll get better life and performance from a deep cycle gel-cel rated at 40-50% larger than the power needed. something like 25 ah would be about right.
the reason for the over size is to avoid discharging the battery to below 25% capacity which would greatly shorten the life of even a deep cycle and isn't good for any battery.