low voltage at idle/ other times

Topic: low voltage at idle/ other times (Read 1964 times) previous topic - next topic

low voltage at idle/ other times

May 06, 2005, 01:26:30 PM

have a 4 channel 200 watt amp powering a 10 subwoofer tube and 6 speakers(with crossover) in a cabinet all mounted in the trunk. at low idle (say red light with foot on the brake) amp cuts out, if i run wiper a/c and headlights amp cuts out. Also the dash starts with the ding ding ding and the alt gauge pops up (digital dash) and shows the amps are at the low end of the scale. Do i need a second battery in the trunk or do i need a bigger alternator. should i go to a smaller amp, say 2 channel 100 watt?
ps it gets worse when powering the mp3 unit through the cig liter socket.

please help

Re: low voltage at idle/ other times

Reply #1 – May 06, 2005, 02:43:51 PM

sounds like altenator. I would check the tension on your belt as well. as slightly better altenator may help with "loudness" of the amp too.

Re: low voltage at idle/ other times

Reply #2 – May 06, 2005, 03:42:22 PM

Sounds like a 3G swap in the makin's :D

Re: low voltage at idle/ other times

Reply #3 – May 07, 2005, 06:44:54 PM

Your stock Alt. should be able to handle much more than just that 4-ch amp, therefore no use for a 2nd battery. As Haystack said, check your belt tension, but also have the Alt. checked, it might be getting ready to go out.
If you do replace the Alt. a higher amperage rating won't make it "louder", but it will give your electrical system some breathing room for when/if you upgrade your sound system or add more 12v accessories. Once everything is working properly again, a small capacitor is always a good investment, sounds like a 1/2 farad would work for you.
Good Luck.

Re: low voltage at idle/ other times

Reply #4 – May 08, 2005, 11:40:52 AM

Quote from: EvilBlackCat

Your stock Alt. should be able to handle much more than just that 4-ch amp.

really>?
why?

Re: low voltage at idle/ other times

Reply #5 – May 08, 2005, 02:30:59 PM

I've never had a problem with either of my 2 cougars with amperage and in the past i've been running about 500w RMS between my two amplifiers. Perhaps i shouldn't have said "much more" just "more". There is a point when you do need to get a larger Alt. but based off of what baylensman said he's below that point.
On monday i'll talk to the master installer at my shop and ask him what the rule/formula was for determining amperage draw so i can get a better/more precise answer for everyone.