QuestionQUESTION: i have a 94 suburban stock alt and battery i installed two amp's 2 awg wire to scoshe dist block with maxi fuse's 1st amp is a ssl ev2500m dropped to 2 ohm's 2nd amp is a jbl 150 older amp not sure model. my voltage drops when i have turned up what do you recommend.
ANSWER: Hi Steve,
How much voltage drop are you getting, and where are you measuring it?
It doesn't hurt to use a large power wire between the battery terminal and the amplifier, but you need to remember that it makes up only half of the circuit. A voltage drop on the ground side of the amplifier circuit will affect the supply voltage just as much as a drop on the positive power wire. All the current running through your 2AWG power wire needs to flow back to the battery and alternator through the chassis and the ground wiring. In a 94 Suburban, that might mean a 12-gauge wire between the vehicle's chassis and the negative battery post.
You can use a digital multimeter to find voltage drops very easily. Just set the meter for DC volts, turn on the audio system and turn it up as loud as you ever normally play it, and place the multimeter probes on any two points in the power line. For example, if you put the two probes on each side of the fuse holder, the meter will show the exact amount of voltage drop through the fuse and fuse holder. If you put one probe on the negative battery terminal, and the other probe on the amplifier's ground terminal (using a long jumper wire), then you'll see the exact amount of voltage that's being lost through the ground side of the circuit. This type of measurement only works when the audio system is playing, though; voltage drops occur when the system is under a load, not when it's at rest.
My guess is that you'll need to upgrade some factory charging system wiring, such as the wire between the negative battery terminal and the vehicle chassis, the wire between the alternator's output terminal and the positive battery terminal, and the wire or ground strap between the engine block and the chassis. These connections are commonly called "the Big 3" in the car audio world.
Hope this helps!
Brian
---------- FOLLOW-UP ----------
QUESTION: i see the drop in voltage on the dash volt meter. i have a feeling it's a ground that is bad. cause even when i use the power windows with the amps off the volt meter drops a lil bit.
AnswerHi Steve,
If you're getting a serious voltage drop through the factory ground wiring, it will affect all the electrical components in the vehicle, including the stock volt meter. To do any serious troubleshooting, though, you really need a digital multimeter. It doesn't need to be expensive; any digital meter found at a hardware or tool store would work perfectly well for identifying a voltage drop.
Good luck!
Brian
