My Portable Battery System - 12volt, 400wrms

Hey guys.

I been running different concepts in my head for a few weeks and have finally come up with what i think is the best system for my goal.

brief:

1.portable for two persons.
2.efficient
3.high quality / Durable
4.comparable to Pro audio, while using Car audio amplification
5.at least 2hrs use at high output using a 110ah deep cycle SLA.
6.professional apearance
7.output to allow dancing around a camp fire for up to 20 people
8.upgradeable

the system will require a set of reletively large wheels on each cabinet, so it can be rolled on grass and moderate terrain like sand. i wanted hron loaded bass, but size was a issue. at the moment i am suing a pd158 for the LF. this will be replaced by a neo 'SB' 15" driver from PD.



anyone got any ideas on a better current limiting approach than using underated fuses and keeping the output just below when the fuse is likely to blow? also, cold someone tel me what they think theoperating times will be using a 110AH sealed lead acidbattery with a current draw of 40Amps and 80Amps respectively.

cheers, and any other comments will be taken on board!

rich

110 aH means amp hours. 110 amps for an hour or 1 amp for 110 hours. but i doubt those amplifers wouldconstantly draw 120 amps!

Instead of using fuses, perhaps investing in some MCBs ( en.wikipedia.org/wiki/Circuit_breaker ) would be a better idea. They're not expensive and if you mount several onto a DIN rail then you could wire them in parallel and only switch one on at a time for different max desired operating times. If a low current MCB consistently trips then just flip up the next on the scale. You could also add a no MCB bypass option with a defeat switch for those times when you just want it loud and don't care about battery life.

Also you could just build a current meter (12v led panel or old style VU perhaps) onto the back of the box and just monitor it by eye. This will give you an idea of how long the battery will last at a given level and won't just shut off the sound which could suck a bit depending on the application.

Edit: Having the battery outside of the box is also a good idea probably. Easier to swap out and charge without unscrewing stuff, and you can connect multiple units if desired. Also makes the box lighter.
Edited by: odc04r

For the current limiting I would use something like a behringer DCX xover and set the internal limiters, there are some mods to this unit if you search on google for running it directly from a 12VDC source should also be able to mod for 24VDC - probs easier as you shouldn't need to step up the voltage.
For amps I used some class D modules from ebay - 60WRMS into 4 ohms @ 24VDC, quad channel boards for £25, remember to make it sound twice as loud you will need approx 10X the power.
For more bass output maybe consider doubling up the drivers on the bass section for increased efficiency.

Edited by: SubSoniks