Battery Help

[llatimer]

I need to build a battery pack. I need about 15 volts and 3 amps of output. Size needs to be as small as possible as I don't have too much room to work with. Any sort of ideas will be very much appreciated. I'm using a battery pack that plugs into the wall right now. I think the output is about 45 watts if that helps. However, I won't be able to plug it into the wall later on.

Thank you in advance.

 

[EEbyChoice]

You need 15 volts and 3 amps, but for how long? This will determine in large part how large your battery pack needs to be. You need to figure out the desired amp hour rating of your application. 15 amps @ 3 volts is 45 watts. If it needs to run for an hour, then you need a 3 amp hour capacity and so on.

 

[llatimer]

It uses a intermittent solenoid so the power needed is not constant, but let's assume I need it to run for about 3 hours.
thanks again for the help.

 

[IRstuff]

Two laptop batteries will give you about 12AHz

TTFN

 

[llatimer]

Do I have any other option? Even if I have to build it myself. Something a little smaller and possibly less expensive?

thanks.

 

[IRstuff]

You could try a conventional sealed battery ala Yuasa.

Your options are limited by the amount of eneryg required. 135 Whr @70 Whr/kg means that you'll need a minimum of 2 kg of conventional battery electrolyte.

TTFN

 

[IRstuff]

cross-posted at thread658-114183

TTFN