220VAC - 12VDC Power Supply - Car Stereo.

crosstownk

I've a big stereo in Mrs. crosstownk's VW Bora. It used to be my car but she doesn't turn the volume up past 2 and always complains about the space it takes up in the boot - 12" DVC sub, 3 amplifiers, a processor and a cooling fan. This stereo can put out in excess of 1kW(rms). I've entered this car in sound-offs and have been reasonably placed. I want to sell the Bora but want to keep the stereo and possibly use it in the house. The problem is I need a power supply for it and it appears that a power supply that can transform 220VAC to 12VDC and supply a current of 100A is next near impossible to come by.

I like my music and my home stereo speakers are knackered so I'd like to replace them with the set up from the car.

What do I do? Does anybody know or can anybody recommend a power supply or will I have to let the stereo go with the car.

Pete67

Your best bet is a large 12V battery and a 20A float charger. The amp will pull nowhere near 100A most of the time, and if it is needed to cope with occasional short peaks, the battery will supply it no problem. Make sure that power supply cable from the battery to the amp are good and heavy, and put a fuse in them!

The alternator in your car will not supply 100A continuously anyway, unless you've upgraded it.

crosstownk

Pete67 wrote: »

Your best bet is a large 12V battery and a 20A float charger. The amp will pull nowhere near 100A most of the time, and if it is needed to cope with occasional short peaks, the battery will supply it no problem. Make sure that power supply cable from the battery to the amp are good and heavy, and put a fuse in them!

The alternator in your car will not supply 100A continuously anyway, unless you've upgraded it.

Yep - I upgraded the alternator. I have 3 amps. One is 4x100Wrms and the other is 4x120Wrms bridged and powering the DVC subwoofer. I've a smaller amp for the HF(tweeters) whose power requirements are minimal. I've considered what you've suggested and I may need more than one battery (and a large cap) but I think it's a viable solution.

Pete67

I'd stick with one battery if you can - it's much easier to manage charging, as you don't have to worry about diode splitters etc. Maybe a truck battery would be suitable, much greater capacity that a car battery would have. If you're using it indoors go for a sealed battery to avoid risk of spilling acid.

Lex Luthor

crosstownk wrote: »

The problem is I need a power supply for it and it appears that a power supply that can transform 220VAC to 12VDC and supply a current of 100A is next near impossible to come by.

100A??????:eek: That would be the size of a house

don't you mean 100mA?

unkel

Lex Luthor wrote: »

100A??????:eek: That would be the size of a house

don't you mean 100mA?

No 100A is about right. 12V * 100A = 1.2KW (a bit above peak output of the amp, which of course is lower than the peak input)

I reckon Pete67's solution will work, but be careful what battery to pick. Aren't truck batteries 24V and as such unsuitable? I think I would look for a high capacity battery like the ones used in a large exec saloon or a big 4WD vehicle

Paddy001

Trucks are 24v becaure two ordinary 12v are joined + to - and the remaining two leads are used for power supply. Use one big battery like a diesel one, or use two joined + to + and - to - and tap each then for power, joining that way will increase power but not voltage.

maidhc

unkel wrote: »

No 100A is about right. 12V * 100A = 1.2KW (a bit above peak output of the amp, which of course is lower than the peak input)

I reckon Pete67's solution will work, but be careful what battery to pick. Aren't truck batteries 24V and as such unsuitable? I think I would look for a high capacity battery like the ones used in a large exec saloon or a big 4WD vehicle

Get a tractor battery!

12v, quite cheap (under €100).



(Edit: I assume trucks use the same ones!)

Paddy001

There must be an easier way though than using batteries... Plenty ov 12v converters about u should surely be able to get the right one

maidhc

http://www.komplett.ie/k/ki.aspx?sku=335150

??

blackbox

Paddy001 wrote: »

There must be an easier way though than using batteries... Plenty ov 12v converters about u should surely be able to get the right one

As well as being able to deliver very high currents, batteries have an additional advantage in that they absorb noise (mains hum) from the charger/rectifier.

zilog_jones

maidhc wrote: »

http://www.komplett.ie/k/ki.aspx?sku=335150

??

Read the specs, that'll only take 72A max on the four +12V rails combined, and I'm not sure if you could combine them safely (I forget this stuff ).

crosstownk

Thanks for the replies folks.

I'll probably go with the 20A floater and a 1F cap which should look after the peak draws on current supply to the bass amp.

Now for the next problem - to build a cabinet for the speakers - DOH!