URGENT: High Current PSU help

[KRNAZNBOY]

Hey guys, i am building a (car) subwoofer that i will be running in my home until i am old enough to have a car. The subwoofer amplifier outputs 350watts, but its efficiency is about 25%, so i need 1400 watts in.

Voltage in is 14.4v (alternator/car battery)

So i need about 100 amps IN @ about 15v

How can i achieve this? without blowing massive amounts of money

Thanks guys! I would like to solve this quick

 

[ARG]

Why not grab a car battery and hook it up to that?

 

[starlight]

I had a couple of friends that did this and used a car battery.

 

[ped]

The subwoofer amplifier outputs 350watts, but its efficiency is about 25%, so i need 1400 watts in.

Why? are you going to be running it at full volume, constantly?

As others have said...just use a car battery.

 

[KRNAZNBOY]

Car battery seems like the only option

But they don't really just have them lying around.... how much do they cost?

 

[starlight]

new car batteries are $100 and up.

 

[ARG]

Yeah, around that price ^

Cheaper than any 15V 100A power supply you're going to find.

 

[KRNAZNBOY]

So there is no way i can convert 120v AC (wall wart) to 12 - 15v DC, without limiting current?

*sigh

EDIT: what about the 12v rail of a computer PSU?

 

[KRNAZNBOY]

What about this?

Sun 300-1523 1500W Power Supply for V1280 E2900

Output 12v - 4a MAX
48v - 30a MAX

The 48v, if stepped down to less than 20v, would work!

But how? Do they sell 750 watt-rated resistors?

 

[ARG]

The 48v, if stepped down to less than 20v, would work!

But how? Do they sell 750 watt-rated resistors?

With a high power DC-DC buck converter would be best.

 

[KRNAZNBOY]

With a high power DC-DC buck converter would be best.

Ill pay you to find me one

seriously

 

[KRNAZNBOY]

Ok i am going with a car battery and a charger.....

If i look up deep cycle battery on ebay i get a bunch of options, lots of them are pretty cheap.

UPG 12V 15AH F2 SEALED Lead Acid AGM Deep Cycle Rechargeable Battery | eBay

Would this one work?

OR
http://www.ebay.com/itm/Belize-Tri-...US_Rechargeable_Batteries&hash=item3f2acf3c74
What kind of charger? This isnt some ordinary li-ion

 

[ARG]

Someone please correct me if I am wrong, but those may not be able to handle the continuous 100A current draw since they are only 15Ah, 7C discharge is quite a bit. IIRC a car battery is 40Ah.

 

[Rifter]

Car battery or very high amperage single rail computer PSU.

 

[djQUAN]

Get a car battery and trickle charger. Connect the trickle charger to the batt 24/7.

The trickle charger can keep the battery topped up when not in use and the battery will provide the high current pulses that you need when playing.

OR

you can build a couple of this and parallel.
http://laserpointerforums.com/f60/high-current-bench-power-supply-89163.html

The server supplies come really cheap in online auction sites and are meant to be paralleled since they need redundancy in the original application.

BTW, what car amp is that? I'm willing to bet that car amps today totally overspec their ratings so you will probably be able to use a lower current supply than you think.

 

[Sigurthr]

Rewound MOT with a high current secondary, very large industrial diode rectifiers, and handful of multi kilofarad supercaps. That's you're cheapest mains derivative system.