Both gives the most information. If the meter in the dash is varying wildly, where you're grounding the amps is not your biggest problem (unless it happens to be by one of the speaker terminals 
). Dirty terminals, corroded cable at the terminals, a soft battery, or bad alternator are all possible. Due to high rotor inductance, the field coil can not source fast current steps and anything quicker than a couple hundred milliseconds all has to come from the battery, so a good battery and connections is very important for audio.
). Dirty terminals, corroded cable at the terminals, a soft battery, or bad alternator are all possible. Due to high rotor inductance, the field coil can not source fast current steps and anything quicker than a couple hundred milliseconds all has to come from the battery, so a good battery and connections is very important for audio.
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The exact regulating voltage is thermally compensated and is determined by the regulator in the alternator, but something above 13.6V in the summer should mean the alternator is OK. Beware that some alternators actually drop out below 1000 RPM while most vehicles idle slower than that. You don't want to see anything over 15 volts either, and no speed modulated voltage over 2000 rpm. For the wiring meaurements, ideally the voltage is the same at the amps, under load, as it is right on the battery terminals. Of course this will not be the case. How big the difference is, is the interesting part..
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So If I understand this correctly. If my battery is measuring 13.6 to say 14.4 .Then the battery and alternator are good. And when the car is revved up to 2000 rpms, and my amps are running hard the power and ground wires connected to the positive and negative on each amp should test at 13.6 and 14.4 volts on each positive and negative wire connected to the amps. Is this correct. Also how do I verify that the seat belt bolt was a good or bad ground.
You've essentially got it, but the battery or connections could be defective and everything can look okay with idle electric load. Checking the ground integrity is not much more complicated than measuring the B+ terminal at the amp against multiple ground probing points. If you catch a significant drop in voltage the closer you get to the amp, you may have a grounding problem in the vicinity. You can also just probe around with the ground terminal at the amp as a reference, whatever you prefer..
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Ditto what Andrew said. You shouldn't see much voltage drop with the sound system on, but no music playing, or on - with heavy bass. If you do, then you know there is a problem.
Start at the battery. If you see little or no drop there, go to the amp terminals. If you see a big drop there then you know you have a wiring problem. Probably the ground, but not always the case.
You are on the right track, it's just going to take some probing around. Good luck!
Start at the battery. If you see little or no drop there, go to the amp terminals. If you see a big drop there then you know you have a wiring problem. Probably the ground, but not always the case.
You are on the right track, it's just going to take some probing around. Good luck!
So if I am understanding correctly.So to check the integrity of my amp grounds. I hold one wire of my volt meter to the negative terminal wire on one of my amps.,and hold the other wire of my volt meter to the spot I'm checking to see if its a good ground. Shouldn't the multimeter be testing in ohms when I'm doing this,and what number should it read. Should it only say).0 to be considered a good ground,or are there other acceptable numbers. Sorry for all the questions,I'm totally new to the testing phase.Thanks to all of you that have chimed in to help.
You're testing for voltage drop. The less, the better. Technically it's the same thing as measuring for resistance, but on the scale of milliohms which is much more difficult with standard equipment than playing some low dynamics black metal or something (pink noise works) at mid-volume and trying to catch the voltage developing across the offending resistance with some large currents through it.
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Ok,I,m pretty sure I have the voltage testing down pat. With the ground integrity test,Where I test to make sure the metal I picked to use as my ground is good. That is solely tested by running the stereo in idle mode,and when it is in driving hard mode,Watching the volt meter to make sure it stays saying the same number reading as when I tested the battery at .Do I have this correct,and if so ,What is the lowest it should drop off,and be considered still an acceptable ground. If I have this correct,I should be ready for the testing phase.Thanks
Hi, I have another quick question for all you experts. I was wondering if there is less resistance ,and if is it better when grounding 3 amplifiers. If it is better to use 3 short ground wires.One for each amp. Each directly connected to the floor pan,as compared to one big wire connected to the floor pan going to a distribution block,and separating them that way. You would think a large 1 or 0 gauge wire used for each amp ground directly to the floor pan would flow the power directly,and eliminate the extra resistance of having to go through the distribution block.,an would be the best. Is this correct? If it is better to use a separate short ground wire for each individual amp,Would all the wires be best to be ran to all the same bolt ,and stacked on each other,and tightened to the floor pan,Or is it better for each of the wires to have its own separate spot away from each other bolted to the floor pan. Thanks
Sorry for the late reply,I got called into work,just after posting my question. I decided to check all my big 3 connections,and when I checked closer. I see that only 1 of the big 3 have been done. This speaks volumes to trusting someone else,and not doing your own work. I just want to confirm what is considered the big 3. I understand it as alternator positive to battery positive), (Battery negative to chassis),and (engine ground to chassis).Do I at least have the big 3 correct? The alternator positive to battery positive is definitely done. With the (engine ground to chassis),Do I install the bigger wire exactly where it is originally installed now.Or is there a better grounding spot for the chassis ground. DO I leave the original wire there,and just add the bigger wire,and totally remove the original one. For the (battery negative to chassis),can I run the larger wire from the battery negative post to the same chassis bolt used for the engine ground to chassis,or will that cause trouble,and if not ,where is the best place on the chassis to mount it. If it helps,or is needed. This is a 1993 ford thunderbird.Thanks
alternator positive to battery positive), (Battery negative to chassis),and (engine ground to chassis).Do I at least have the big 3 correct? The alternator positive to battery positive is definitely done. With the (engine ground to chassis),Do I install the bigger wire exactly where it is originally installed now.Or is there a better grounding spot for the chassis ground. DO I leave the original wire there,and just add the bigger wire,and totally remove the original one. For the (battery negative to chassis),can I run the larger wire from the battery negative post to the same chassis bolt used for the engine ground to chassis,or will that cause trouble,and if not ,where is the best place on the chassis to mount it. If it helps,or is needed. This is a 1993 ford thunderbird.Thanks
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