12V System On A Shoestring Budget

After looking at some of the systems on here and a friend's 12V system that he puts together, I have decided to make my own. Now as this is more of a "for fun" project and will only get occasional use, I dont really want to spend any large amount of money on it. And as such I realise it wont be as loud or efficient as some of the guys on here. Im not after a work of art or a miracle, just something that works :P

So far I have:
 - Pair of Kenwood hifi speakers (80W each)
 - Pair of Mordaunt Short hifi speakers (25-100W each)
 - Flat pack bookcase that works nicely as a frame to mount everything in

Still need:
 - Amplifier(s)
 - 12V battery
 - Mixer

Amplifier
A quick look on ebay threw up this:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380247207292&ssPageName=STRK:MEWAX:IT
Now I dont believe the 500W for a minute but the specs state 75W per channel RMS. My question to you guys is, do you think it would be good enough to power one or both (parallel wired) pairs of speakers? (The speakers are 8ohms each). For £9 it certainly seems worth a pop.
I have also been looking out for used car amplifiers on ebay from actual brands too.

Battery
In the process of getting hold of a 45Ah, relatively new battery. Hopefully that will all work out, otherwise testing might have to be done next to the car.
My question here is, whats that best way to go about charging a 12V battery? So far I have seen little trickle chargers that are a transformer that plug into the wall on ebay for ~£6. I have also seen solar trickle chargers which seem attractive for top-ups in places further away from mains. What would you guys reccommend?

Mixer
Not done much research into this as it is not really a vital piece of kit. If I do get one, it only need to be a tiny jobbie with 2 or 3 line inputs and possibly a mic in. As a quick example, something like this http://www.gear4music.com/PA-DJ-and-Lighting/Behringer-Xenyx-502-Mixer/6PE would be ample.  However I cant seem to easily find a mixer that can easily be connected up to a 12V supply and I dont particularly want to buy an inverter, just to use a transformer again.
Another option would be to knock one up myself. I dont think it would be TOO hard. Has anyone made their own 12V mixer before and have a schematic they know works well?

Anyway, thats enough of my essay, i'll get some pics of the mockup frame and speakers asap and hopefully someone can answer my questions.


Edited by Blaize110 - 26 July 2010 at 5:47pm

seeing as mixer isnt a huge important thing to you..  why not try one of those little 9v battery powered mic/line mixers from maplins?  4 mono channels so i guess you could modify it to play 2 stereo channels for a pair of ipods.  the mixers are about £10-15 each i think.  they might even do a dedicated line mixer is the same sort of format.

That amp looks good. Thats probably the one i'll go for then.

One question though, whats the best way to achieve the 24V to power it. Should I wire up 2 12V batteries together? In which case, do they need to be the same type/model? Or is there a better way such as a step-up transformer?

I have read that it will run on 12V but the sound quality is much better at 24V.

2nd that.

definately worth £5 more for the sure amp.  they are superb and will have an idle current about 1/10th of the idle current of those car amps.  this means that you will probably get at least double the amount of run time from the sure amp.