power supply issue

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=90306
Printed Date: May 15, 2024 at 3:50 PM

Topic: power supply issue

Posted By: dwarren
Subject: power supply issue
Date Posted: February 10, 2007 at 12:58 PM

I have a customer who has a car audio setup installed in his restaurant. He has a deck, changer, xm piece, and a small four channel mtx amp, thunder 404. This amp has two 25 amp fuses in it.

The problem: His current battery and trickle charger do not keep up. The battery winds up dead, usually. The trickle charger is rated at 5 amps. This essentially mocks a car with too small of an alternator and the battery takes the beating.

A solution, maybe? I can get my hands on a power supply that produces about 18 amps, but I am concerned that this will not keep up with the draw, as the music is blasted all day at this restaurant. In addition, this power supply will eliminate the battery as per suggested by the sales man.

So what's the verdict, is the 18 power supply gonna keep up?

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Replies:

Posted By: the12volt
Date Posted: February 10, 2007 at 1:02 PM

I use an Astron RS-70A to run the system in my garage without a battery. You can find Astron power supplies here: https://www.astroncorp.com/linear.shtml

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Posted By: dwarren
Date Posted: February 10, 2007 at 1:14 PM

Funny you list that model, that's the one I was just looking at in our show room. In fact I ordered an Astron model previously, the 35 amp model, but thought it to be too big, and it didn't have a low power mode or trickle mode when the stereo in not on full blast.

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Posted By: haemphyst
Date Posted: February 10, 2007 at 9:07 PM

A power supply will only make as much power as is demanded of it. Just because you have a 70A (940 watt) power supply, that doesn't mean its always going to MAKE 70A (940 watts) or pull 7A (940 watts) from the wall... If the amplifier is only wanting to make 150 watts, then the power supply will only have to come up with that much power, and will only pull that much power from the wall. The "low-power" mode or "trickle" mode is automatic.

Even though your system may say 50A, peak, it's always better to have too much current available. Your car battery CAN make 700A to 1000A, but do you always use that much? Same story with an analog power supply.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."