LOW Voltage Promblem
 

I thought maybe someone here can help out. A friend of mine is running a 1000 watt fosgate amp (500x2 brigde mode) pushing two kicker sola barics (the square subs). This is the second amp he has tried and it keeps kicking off the fist was some mono kenwood amp. He has measured the voltage at the amp and it gets down to 10 volts. This is the only amp he is running. He is running 4 awg from the battery to a 1 farad cap and it is grounded to the trunk floor. He thinks the promblem is that the the factory ground from off his battery goes in to some sorta of connector were many things ground and his says the wire is kinda small. The cars is a 99 monte carlo, I had the same amp pushing 2 12s also with another amp pushing the 400watts powering the highs both running of the same 1 farad cap. This was in a 99 sentra with the standard small altenator and I never had any cutting out and I played it loud for extended periods of time. I know they have a couple of you who have been doing the sound thing for a long time. Any ideas?

Tony

I gave him the 120amp circuit breaker I was using. I just don't see how we can do the ground any better.

Tony

Check the alternator output. It should put out 13.5 - 14 volts. Check it with everything on, both at idle and at 2000 rpm. As to running the ground back to the battery, wrong idea. Ground no longer than 15" to a bare metal source (trunk floor). Just make sure the gas tank isn't under there. Make sure you use the same size wire for power and ground.
Your fuse size should be 5-10 amps larger than the total current draw of your amps. Easy way to find this is to add the total amount on the fuses in the amp (2 25 amp fuses = a 50 amp current draw. You would use a 60 amp fuse). Also, since it's a GM, make sure you're using a GM style Battery Tap, not sliding the wire under tha factory cable. You'll get a better connection -w- a tap.

I kinda find that a hard one to swallow. I've been an MECP Certified Installer for 10 year's and have never seen a high power system burn up from proper grounding to a bare metal source. I've seen 'em burn from improper or loose grounds, but not from a proper ground. I have seen and heard systems get alternator whine from long ground loops though. If anyone's interested, check the Rule Guide from IASCA (International Autosound Challenge Association). They set the requirements for installation by IASCA competitiors in both SPL and SQ. It's cool reading, especially if you're thinking of competing.
My $.02 worth.......

Sounds like you answered your own question. 2 amps were improperly grounded and 1 was a POS. I've seen some pretty crappy work in my years too, but most from amateurs or non professional hack shops. No one is perfect. 17 volt system? Last I heard, car's were 12 volt. High power alternators are based on amperage, not voltage. ex - 14 volt, 250 amp alternator. Hell yeah 17 volts will burn a car. As far as IASCA being about the money, yeah it costs to compete. It costs alot to drag race too. I guess the NHRA is all about the money too. IASCA's guidelines are followed by db Drag, USACI and are the recommendations of MECP, most Installer's schools and Auto Sound Manufacturer's. If all of these organizations and schools are recommending this way, sounds good to me. I'm not saying your friend doesn't know what he's doing. I'm sure he does. I'm just trying to help out a fellow Pro owner with a problem. Don't get yourself all worked up.

hey toolopro, i went to your page and there was a pro with a protege-tech decal on the winshield. do you know who that is? the old timers on this board (me included) came from that forum. just curious is all. :)

Yup. I came from there too. Haven't got my Memphis Banner cut yet. It'll be replacing the old sticker soon.

Yeah, voltage is important to good amps. My memphis will handle up to 18 volts as well. But they also draw 160 amps of current. Amperage is just as important. Yeah, I learned all about Auto electrical when I took my ASE tests. Haven't seen too many 18 volt alternator's at the local Napa. Have seen some 14 volt, 120 amp Caddy one's though. Put one in my 65 Ranchero to help with the current draw from the stereo system. Oh, and NHRA has this cool class called Street for everyday Joe's to have some fun. So does IASCA. It's called Consumer Class. db Drag (the sanctioning body I compete in) has one called Street. So, no you don't have to have millions to compete. Run watchya brung. Of course, if you want to be a contender, you'll spend some bucks and get bigger. It's called competition. Some people do it, some complain when they can't.