voltage drop, third battery or upgrade alternator?

i have a 02 gmc envoy. have a audiopipe 3000 with dd9515. stock alt is 150A, with secondary deep cycle battery. i'm still getting a huge voltage drop and amp going into protect. can i add a 3rd battery or do i need to upgrade alternator?

Big 3 (read the sticky) and alternator.My ex once told me I have a perfect face for radio.

Big 3 and alternator. All the third battery will do is create yet another device that the alternator now needs to try and charge. If it can't keep up with 2 batteries, how can it with 3?Top Secret, I can tell you but then my wife will kill me.

thanks for the help guys. i finished the big 3. but now my amp is half blown. I've been looking at replacing it with a dd m4b would i need a 300amp alt or a 250? i havent purchased anything yet just want the most power out of my sub.

Yes. The most simple solution may be to get a capacitor. Some people say they are useless, but that's because they don't know what they're talking about. A capacitor simply stores a charge of electricity and dispenses it when it's bumping hard. Do your lights flicker? Can you turn on all of the accessories and still crank it? I have 9600 watts of amps, 2-4000 watt Class D's with one at 2 Ohms and the other at 4 Ohms. I also have a 1600 watt 4 channel amp. I running 4 15 inch ported subs . I have two 900 CCA deep cycle batteries and 2- 3.5 Farad caps. I don't want to ever see my lights flicker because it can lead to ignition problems, premature battery failure, dead batteries, and if your girlfriend wants you to crank it, and it's the middle of summer, and you have to turn off the A/C every time you hit a traffic light...good luck getting a kiss while her make-up is dripping down her face.Pegleg Charlie

Builder-Charlie Cannon Subwoofer Enclosures and general troublemaker at

LMMFAO Corp.(LOL)

I forgot this...do the big 3. I have 50 feet of 0/0 cable in my truck. at least 20 feet of that is chassis to frame rail alternator to firewall, bed to frame rail, bed to cab. I'm grounded six ways to Sunday. Grounding is perhaps the single most important factor after ensuring good connections. Grounding provides a path for the return of electricity back to the battery. You cannot have too much or too many grounds. That could even be your problem. Also, I don't care if you already have additional grounds from your engine to the firewall or not, add some using 0/0 cable or good quality grounding straps.Pegleg Charlie

Builder-Charlie Cannon Subwoofer Enclosures and general troublemaker at

LMMFAO Corp.(LOL)

Forbidden and geepherder are both well known here and I believe are 100% correct. If the Alternator can supply the needed current, the voltage should remain stable and healthy. Batteries provide the under supplied current for short bursts but still must be charged. If you are generating enough juice to power everything there should be no dimming and be able to run A/C, lights, whatever. Proof is in the voltage, plain and simple. If you can't supply enough power for demand, You can ground every square inch of metal twice and the problem will remain. Test bench, fiberglass boat or store display you must generate enough energy first and foremost. Next you must have the capacity to get the energy where it needs to go. Using the correct gauge wire should go without saying. The Big three makes up for manufactures saving weight and money. No reason not to do the Big 3. This is how the use of cap(s) was explained to me: Cap(s) aka Stiffening Cap(s)are small container(s)used to top off a bucket(battery). They keep the bucket topped off and fill in for occasional leaky drips (enter the stiffening part of the term Stiffening Capacitor). The Cap dumps what ever it has for as long as has to keep things full, but it empties within fractions of seconds. Ex: attach an incandescent bulb and see how long it lights, recharge cap again, how long does it light? No longer than the first time. All the Cap can do is get more water from the bucket and try to add small amounts back in. Despite what marketing companies claim, a cap can't make energy or be substituted for an inadequate source. The battery supplies what the alternator can't (the remaining water in the bucket. More battery capacity = bigger bucket). Solution, get a hose (HO alternator) that can keep the bucket(s) continuously filled. If the supply keeps the bucket filled under load, a Cap could be useful to stiffen the voltage. If you are are serious SPL competitor it might be worth the time and money.    You are fortunate you own a GMC vehicle which means there are plenty of readily available HO alternators. Installation should be straight forward and simple.

pegleg1960 wrote: Yes. The most simple solution may be to get a capacitor. Some people say they are useless, but that's because they don't know what they're talking about. A capacitor simply stores a charge of electricity and dispenses it when it's bumping hard. Do your lights flicker? Can you turn on all of the accessories and still crank it? I have 9600 watts of amps, 2-4000 watt Class D's with one at 2 Ohms and the other at 4 Ohms. I also have a 1600 watt 4 channel amp. I running 4 15 inch ported subs . I have two 900 CCA deep cycle batteries and 2- 3.5 Farad caps. I don't want to ever see my lights flicker because it can lead to ignition problems, premature battery failure, dead batteries, and if your girlfriend wants you to crank it, and it's the middle of summer, and you have to turn off the A/C every time you hit a traffic light...good luck getting a kiss while her make-up is dripping down her face.

9600 watts?! What alternator are you running? Can you recommend a good cap? I checked all the ones on Amazon. A few people were testing them and the caps weren't putting out what they were rated for. A couple people cut open the cap and discovered instead of a coil of aluminum and paper, it was just a bunch of little caps soldered on a circuit board.