draining battery

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csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 16, 2007 at 7:49 AM / IP Logged

What happens with an amplifier and /or speakers when the system is played at maximum performance but with the car switched off, ie. the battery does not get charged - battery voltage lower and lower. will the amplifier's power supply get damaged due to inconsistant battery supply, will the amplifier start to clipp the signal where it didn't before? Just need some expert opinions. Had an amplifier to repair recently and was told that it was played with car switched off.

Marius Minnie

KPierson

Platinum - Posts: 3,527

This member consistently provides reliable information

Joined: April 14, 2005

Location: Ohio, United States

Posted: August 16, 2007 at 11:56 AM / IP Logged

It depends on the amp.

I used to have a Kicker ZR600 that had a fully regulated power supply (made the same power at 12vdc as it did at 16vdc).

However, once the voltage started dropping the amp would pull more current to compensate. If the voltage got too low it would blow the 3 30A fuses in the side of the amp. As long as battery voltage remained high I didn't have any problems.

Different amp manufacturers use different power supply technology. It is very possible that a low or unstable voltage damaged your amp. Instead of asking us if it is possible you should be asking them exactly what parts they replaced and why they think fluctuating voltage caused the problem.

Kevin Pierson

csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 17, 2007 at 5:27 AM / IP Logged

It was a Camtec MIG1500 (not a known brand in the states). The amplifier has an unregulated power supply and therefore I suspect that the cause could have been due to insufficient battery power.

The power supply PCB is destroyed, even melted the heatsink plates/aluminium brackets clamping the fets to the heatsink. I will try to load the pictures on the web.

Can you explain how a power supply reacts in the case of draining battery power?

Marius Minnie

csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 17, 2007 at 6:01 AM / IP Logged

Here is the link to the images. draining battery -- posted image.

Marius Minnie

csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 17, 2007 at 6:06 AM / IP Logged

www.freewebs.com/autoaudiorepair/mig1500.htm

Sorry

Marius Minnie

KPierson

Platinum - Posts: 3,527

Joined: April 14, 2005

Location: Ohio, United States

Posted: August 17, 2007 at 6:10 AM / IP Logged

There are too many variables in a power supply to guess. How low was your battery voltage getting?

It may be possible that the supply voltage was falling below the minimum operation voltage for some of the components, which could effect their operation. It's really hard to say. If it is a voltage related issue, and you say the circuit board is melted, I would think that the voltage would have to be really low for a long period of time to create enough heat to melt the board, unless there is evidence of a small fire.

Kevin Pierson

csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 17, 2007 at 7:30 AM / IP Logged

I have no idea of the actual voltages at the time, but for arguments' sake lets say the system was set up with a voltage of +/- 13.5V. If it was played for a period of time without the engine running, with the voltage going down to about 11V-10.5V, what could happen? (This is a 3000W max / 500W RMS, one channel, class AB amplifier. The owner connected 2 x SVC 800W Kenwood subs = 2ohm load with apparently only 8guage power cable.) Did you have a look at the pictures?

Marius Minnie

KPierson

Platinum - Posts: 3,527

Joined: April 14, 2005

Location: Ohio, United States

Posted: August 17, 2007 at 10:27 AM / IP Logged

No, I could not load the pictures for some reason.

Again, it is hard to say how it will respond at lower voltages. Typically, in a non regulated power supply you're output power will drop as your input voltage drops. I wouldn't expect that to damage a quality amplifier though.

Kevin Pierson

aznboi3644

Gold - Posts: 2,600

Joined: May 01, 2006

Location: United States

Posted: August 17, 2007 at 4:25 PM / IP Logged

I know that the old Orion HCCA amps were unregulated and if the voltage got too low they would fry...they could handle high voltages though but they didn't like anything lower then like 12 volts for too long

csound

Member - Posts: 18

Joined: July 27, 2006

Location: South Africa

Posted: August 20, 2007 at 3:02 AM / IP Logged

I'm looking for a technical explanation for what happens inside the amplifier when the voltage gets too low. My explanation is as follows; let me know if this sounds logical: The "Orion" amplifier is set up for maximum performance at a voltage of +-13.5V. If the voltage drops (the output rail voltage will also drop) then the amplifier will start clipping the signal, which means that the power supply will have to supply more current at a lower supply voltage. The power supply FETS will overheat and burn out.

Marius Minnie

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