[LAU] [OT] Building a battery powered PA

[Jörn Nettingsmeier]

On 05/27/2010 06:36 PM, Bob van der Poel wrote:
>> A friend of mine was talking about how he would like to be able to busk with
>> his keyboard, and I said I would look into the possibility of building him a
>> battery powered PA for it. Does anyone have any suggestions for good ways of
>> going about this? We would like to keep the cost as low as possible.
>>
>
> How about an off-the-shelf UPS? Don't know how big you'd need, would
> depend on the gig time, etc. There is probably a way to calculate that
> :)
>
> The consumer UPS units I've see all have lead-acid (sealed) batteries
> and are quite reliable.

not really recommendable for a permanent setup. with an ups and standard 
mains equipment, you will waste battery (and carry dead weight) twice: 
in the inverter that generates grid voltage from the battery, and in the 
PSUs of your gear that will re-transform the precious grid voltage back 
into low-voltage DC. throw out the middle man.

the nice thing about car equipment (as a previous poster has suggested) 
is that all the gear is standardized to work at 12 volts dc. many car 
radios have line ins these days (for file players etc.). it's easy to 
hook up a small mixer here - you should be able to find a cheap one by 
the Brand That Shalt Not Be Named or one of the other manufacturers they 
steal their designs from - i've seen a few that take 12v dc.