I've run into a problem. When I run my amp at 4 ohms-2 channels, I dont have any issue with voltage drops and lights dimming when I turn the stereo up. But, when I run the amp at 2 ohms-1 channel (bridged), I get a serious amount of dimming from the lights, and the voltmeter drops accordingly. If I hold the brakes, turn the ac on, the blinkers, or anything else, it drops the power system down ever further. I got a multimeter and put it on the contacts at the amp, and saw a 1v drop every time the bass spikes and the amp works hard. It goes from 13.3 down to around 12.3. The more accessories that are on, the lower it goes. I got it down to around 10-11V at one point at idle. I dont see this drop at the battery, but I see it in the lights and other accessories. Here are some specs of the car/system.

-105 amp alternator (2-3 months old)
-425 watts max mosfet Jensen amp w/ 30 amp fuse
-4-5 gauge power wire for 15 feet. (battery to dist. terminal)
-10 gauge power wire for 3 feet*(terminal to amp)
-8-9 gauge ground wire at exactly 1 foot (amp to ground)
-Interior speakers are not amped

The two bolded lines are what I think is the problem. I know I need a bigger power wire for the 3 feet, but thats what the scosche kit came with, and I'm in the power ratings if I remember correctly. I also dont like the gound size. The speakers are louder and sound better at 2 ohms, but I dont want to kill another alternator or battery. Before I spend some money (tight at the moment) on new wires, should I check anything else? I have friends with massive systems that dont dim stock alternators and batterys, so what gives? And, If i do need new wires, is the 4-5 gauge ok, or does that need to go lower also for 425 watts max

You need some serious wire upgrades.

First off your amp ground should be ATLEAST at large as the power wire if not larger. I dont care how short the lead is.

You need to look into the big 3. It solved all of my dimming problems and there is a good chance that between the big 3 you you cleaning all your battery connections and chassis grounds that your dimming will greatly reduce.

you need to label which gauges go where and for what. Just telling us that there is a 10ga lead in your car that is 3 feet long means nothing. I have one too, it probably goes to my starter though.

*updated the first post.

The 10 gauge wire is between the 5 gauge and the amp. I'm never buying one of those scochee kits again. I guess you get what you pay for. How much will upgrading "the big 3" cost me?

10-15 feet of 4 gauge and 6 4ga ring terminals. You could get away with using welding wire if you are on a very tight budget.

What is the largest size wire your amps power and ground terminals accept? Likely 4ga. If that is what it is, you should run 4ga directly to it.

I've never heard of 5ga wire...I would like to see a link to it.

I know what he is talking about. The Schoshe kit does indeed have wire labeled 5 ga.
I saw it on a kit also. It is in between 8 gauge and 4 gauge. I had never heard of it either till I seen it in the kit.

I may get flammed for this, because alot of people here say not to use them, but If he will get a 1 to 2 farad cap, most of his headlight dimming will go away. I have always used caps on every system I have had, and I have had NO headlight dimming. However I use no less than 4 gauge power AND ground.

He may also want to check to see if he is getting a good ground for the amp. No paint, and tight connections.

Tim

Lowrider are you using a power distribution block, to split the power cable from 5 guage to 10 g before the amp ?
If not, how are the 5 and 10 guage wires joined ?

It sounds like you have a bad ground from the amp to the frame/body. Make sure that the gound is to a piece of metal that has no paint on it (sand or grind the paint) paint will not conduct electricity.
Also make sure that the ground wire is tight.

The "Big Three" could also be your weakest link, think about upgrading these wires.

Good luck,
Dutch

also dont forget guys, he has a 2 channel amp, briding a 2 ohm load is the same as paralleling again.. so your actully showin the amp 1 ohm



if you really wanna run a 2ohm load, yes upgrade the wiring, but also look to put your subs to 4 ohm then bridge, that would show a 2 ohm load to the amp.. thats the way my MOJO is set up dual 2 ohm coils, series to 4 ohm, bridged at the amp (the 2000x is a 2 chan amp) showin it a 2 ohm load

maybe i wrote that wrong, or its a missunderstanding. My subs are 4 ohm svc. So paralleling them is 2 ohms on 1 channel. I am going to fix the ground and short power wire with a larger gauge and see what happens for now.

parallel the sub you get 2 ohms right even with out bridging the amp you still show 2 ohms
then when you bridge that 2 ohm load at the amp you are effectivly paralleling the 2 ohm load down to 1 ohm

I dont think so. This should be two ohms. (I know its a 2 channel amp bridged to 1 channel, but that shouldnt reduce the load from 2 ohms to 1)