Any Electronic Whizzes Fancy Helping A Mentally Challenged Lad?

[RKelby]

Right, I'm giving myself a little project to keep me occupied on week nights whilst my GF is at uni. I have decided to build a portable sound system that I can use when camping at various BTCC races and festivals. Therefore it will not be car battery size and hopefully will be rechargeable as I'm basing it on a 3ft x 1ft x1ft box. I'm yet to decide on speakers but they wont be anything stupidly powerful.

I have found what seems to be an ideal amp looking at other forums but my question to you clever people is how do I supply this amp with a constant 12v 2a supply from a battery?

Here is said amp, specs are on the page

http://www.amazon.co...29856117&sr=8-1

I'm confused as to how I make sure the amp is getting the required power fed to it, am I right in thinking as long as the battery is 12v the amp will just draw the 2A as and when it is needed? The battery will also need a fairly large capacity, but just a prod in the right direction will help me out a bunch.

Cheers

P.s I'm not mentally challenged even though I did have a Corsa in past times, what was I thinking!?

Edited 21 February, 2012 by RKelby

[cjb]

am I right in thinking as long as the battery is 12v the amp will just draw the 2A as and when it is needed?

Yes, basically.

The battery will also need a fairly large capacity, but just a prod in the right direction will help me out a bunch.

If it's portable, look for a sealed lead acid. Search for SLA Battery on ebay. Choose 12v and the biggest Ah capacity you can carry. You'll need some way to charge it too.

[RKelby]

Cheers for the quick reply, answered my question. I'll have a look now.

Thanks

[sparky2]

Hi Mate, You will need a DC power lead (prob comes with amp) fused at about 5 amp and about 1.5mm cable with prob neg outer input to the amp, battery wise it all depends how long you will need the amp on for but if it draws 2 amp a 10amp/hour battery would last 5 hours if its in good condition and fully charged to start with so a larger amp/hour battery would last longer. like the posts above go for a sealed lead acid battery or a caravan battery which are designed for slow discharges, if you wanted to top it up then a solar panel would do it but you would need a fairly large panel say 50watt so it would put about 4 amp into the battery (about £300) cheers - Stuart

[RKelby]

Hi Mate, You will need a DC power lead (prob comes with amp) fused at about 5 amp and about 1.5mm cable with prob neg outer input to the amp, battery wise it all depends how long you will need the amp on for but if it draws 2 amp a 10amp/hour battery would last 5 hours if its in good condition and fully charged to start with so a larger amp/hour battery would last longer. like the posts above go for a sealed lead acid battery or a caravan battery which are designed for slow discharges, if you wanted to top it up then a solar panel would do it but you would need a fairly large panel say 50watt so it would put about 4 amp into the battery (about £300) cheers - Stuart

Awesome, cheers for that. One more thing that I'd like to clear up, would the amp draw a consistent 2 amps from the battery whilst powered on or is that the peak draw?

[cjb]

Awesome, cheers for that. One more thing that I'd like to clear up, would the amp draw a consistent 2 amps from the battery whilst powered on or is that the peak draw?

It will depend on volume. It may rise above 2A at peak for a very short burst, but idle it will draw a lot less.

[jjc]

You could always use one of this type of thing to power it, also doubles up as a compressor and starter :-) and will come with a mains/car charger.

http://www.ebay.co.uk/itm/12V-900A-HEAVY-DUTY-CAR-JUMP-STARTER-START-BOOSTER-CABLE-LEAD-BATTERY-BOOSTER-/170765540243?pt=UK_Recovery_Tools&hash=item27c26b5b93

John

[sparky2]

Hi JJC it would be handy but its only a 12ah battery inside. cheers - Stuart

[Jabbasport]

What kind of time do you want the battery to last? Are you bothered about weight?

[RKelby]

I have it all sussed out now thanks guys, a bloke at work has some gear that is ideal so I'm going to have a look later.

[GentleGiant]

As a Class "D" amp, it will draw very little current when you are not using it, and even at full (undistorted) output, it wont draw 2amps.

Be careful not to run it too loud as 10% distortion will blow the cones out on even 100w speakers (as well as making your ears bleed).

Despite the manufacturer's claim of 20W rms per channel, in reality its usable output is far short of that. Their 20W claim is into 4 ohms and at 10% harmonic distortion - and that's acceptable to no-one. Into 8 ohms and at a reasonable distortion level of, say, 0.1% we're looking at around 6-7W per channel, but they really are 'genuine' watts, not hyper-inflated ones, so it seems adequately loud. And by golly, it sounds good too!