Is this voltage drop due to wire length?

[ShadeTreeMechanic]

Normally a voltage source is measured + to - but with a connection you would measure from one side to the other. Like with the + probe on the ring terminal and the - probe on the thing it is bolted to. With the system under full load, start by measuring the total distance of the whole wire and all connections included. Then start narrowing it down connection by connection. You might find that 10 connections each drop 0.1v and they all add up.

[RooTxBeeR]

Normally a voltage source is measured + to - but with a connection you would measure from one side to the other. Like with the + probe on the ring terminal and the - probe on the thing it is bolted to. With the system under full load, start by measuring the total distance of the whole wire and all connections included. Then start narrowing it down connection by connection. You might find that 10 connections each drop 0.1v and they all add up.

Copy that, I never knew you could measure a voltage reading like that. I did all other with a resistance measurement before installing everything and everything read a .1 or .2 at most, but the DMM read .2 naturally. Will have to try that out.

[reedal]

Have you clamped your alt to see what amperage its outputting?

So, to recap, you measure 14v at your battery at all times, even when you're full tilt? But at the amp, you're reading as much as 1v less when full tilt, but read 14v at all other times?

[RooTxBeeR]

Have you clamped your alt to see what amperage its outputting?

So, to recap, you measure 14v at your battery at all times, even when you're full tilt? But at the amp, you're reading as much as 1v less when full tilt, but read 14v at all other times?

I have not clamped my alt, the shop that put it in did but didn't say what they read, they just did it because they thought the alt was dead. Completely different story.

To the recap. My battery is always showing 13.8 at lowest, to 14.1. I did check to see of any drop when bass initially hits, and there is some. I dropped to 13v flat with a sine wave coming on at full tilt. It will go back up to 13.8 13.9 in a split second, but the rear will continue to show low 13v even when the alt picks back up and is charging high again.

[reedal]

On a sinewave, full tilt? I think you're fine personally. Drop a second battery in the back, that will stabilize it some with the added capacitance

[RooTxBeeR]

On a sinewave, full tilt? I think you're fine personally. Drop a second battery in the back, that will stabilize it some with the added capacitance

It's a 700 watt amp, and a 280a alt. I am pretty sure there should be absolutely NO difference in voltage between what the front and back see. Once the fronts voltage came back up, the back never did. I could see if both stayed at 13v, and I actually had a serious current draw, but theres no way I am pulling over 100a.

[MrSkippyJ]

so the back starts out the same but once it goes down it doesn't go back up?

[RooTxBeeR]

No they both will drop when the bass starts, the front immediately pick back up but the back will stay as long as the current draw stays.

[08tahoe]

Your volt meter is probably fucked or the wire going to it has a lot of resistance. If you check your voltage with a dmm right where the volt meter is at do you get the same reading with the dmm?

[RooTxBeeR]

Your volt meter is probably fucked or the wire going to it has a lot of resistance. If you check your voltage with a dmm right where the volt meter is at do you get the same reading with the dmm?

Yes the volt meter I have in the car reads the same when compared to a fluke dmm