Alternator not putting out full voltage at idle

[Kyblack76]

the larger the alternator (generally) the less they make at idle.

what does your car idle at? if its too low the alt may not be making enough to even cover what your car needs.

Also sometimes a bad batt can cause idle to have a lower voltage than normal

The 370 has a smaller pulley to help Idle

Thats why i asked if batt was possibly bad... just guessing at this point. i'd work my way from batts to wiriring to the last thing being the alt. Start with the simple problems and work to the complex.

it drops down to 12 - 12.3v seems really low. Definately checking the battery is a good idea

Dropping that low, seems to me the 370 isn't turning pm much. If hardly at all. 600 rpm, for a large alt isn't much. I suggest moving to a smaller higher idle output alt or keep your foot on the gas. Again. Bigger isn't always better in all cases. But I don't know his set up.

Edit - ideal would be to clamp the alt at idle, and run full tilt. Bet hell be a but surprised of the out put on a 370 at 550-600 rpm

[Smoove]

the larger the alternator (generally) the less they make at idle.

what does your car idle at? if its too low the alt may not be making enough to even cover what your car needs.

Also sometimes a bad batt can cause idle to have a lower voltage than normal

The 370 has a smaller pulley to help Idle

Thats why i asked if batt was possibly bad... just guessing at this point. i'd work my way from batts to wiriring to the last thing being the alt. Start with the simple problems and work to the complex.

it drops down to 12 - 12.3v seems really low. Definately checking the battery is a good idea

Dropping that low, seems to me the 370 isn't turning pm much. If hardly at all. 600 rpm, for a large alt isn't much. I suggest moving to a smaller higher idle output alt or keep your foot on the gas. Again. Bigger isn't always better in all cases. But I don't know his set up.

My 370 is doing great. Great ide output at 14.8v even hot. I can demo on the 6k at idle and not drop below 12.8 and and revving not drop below 13.7. NO complaints about the 370 here.

[ToNasty]

What year and vehicle is this

[Kyblack76]

the larger the alternator (generally) the less they make at idle.

what does your car idle at? if its too low the alt may not be making enough to even cover what your car needs.

Also sometimes a bad batt can cause idle to have a lower voltage than normal

The 370 has a smaller pulley to help Idle

Thats why i asked if batt was possibly bad... just guessing at this point. i'd work my way from batts to wiriring to the last thing being the alt. Start with the simple problems and work to the complex.

it drops down to 12 - 12.3v seems really low. Definately checking the battery is a good idea

Dropping that low, seems to me the 370 isn't turning pm much. If hardly at all. 600 rpm, for a large alt isn't much. I suggest moving to a smaller higher idle output alt or keep your foot on the gas. Again. Bigger isn't always better in all cases. But I don't know his set up.

My 370 is doing great. Great ide output at 14.8v even hot. I can demo on the 6k at idle and not drop below 12.8 and and revving not drop below 13.7. NO complaints about the 370 here.

No sir. I feel you IF YOU can keep idle up. Some can't. We couldn't stay over 550 rpm in on long runs. We had 2 370 and 2 270s. 370s would peace out around 600 rpm. Basically.

Again, you need what works for YOUR set up. Lets.say his car idles at 600. Then he leans on it it will drop. Asking a high out put 370, that's more build for top end to do anything at 500 rpm is asking alot. Just sayin

[Smoove]

OP, what VM are you using? Where is it connected?

[Wasteland_Audio]

Ok so just to clear things up I have a 2004 Suburban, a single 370 alt, big 3 done, alt - front batt - back batts with 2 1/0 CCA to the rear plus 1 4 guage for the high end amp, 4 55ah batts in the rear. 2 5k amps on 2 DC lv6s. I'm using a cheapo vm on the back batts that i calibrated with a multimeter.

[ToNasty]

Your trucks idle fluctuates between 520 and 540. Just like my silverado.

[Smoove]

Ok so just to clear things up I have a 2004 Suburban, a single 370 alt, big 3 done, alt - front batt - back batts with 2 1/0 CCA to the rear plus 1 4 guage for the high end amp, 4 55ah batts in the rear. 2 5k amps on 2 DC lv6s. I'm using a cheapo vm on the back batts that i calibrated with a multimeter.

Do you have at least 2 frame grounds in the rear?

[rocking.that.eclipse]

Take a DMM to the front batt without the car running and report back what you sitting voltage is.

Also if it is above 12.5 I would still take it into autozone and have them load test it to make sure a cell in the batt isn't bad

[Wasteland_Audio]

Ok so just to clear things up I have a 2004 Suburban, a single 370 alt, big 3 done, alt - front batt - back batts with 2 1/0 CCA to the rear plus 1 4 guage for the high end amp, 4 55ah batts in the rear. 2 5k amps on 2 DC lv6s. I'm using a cheapo vm on the back batts that i calibrated with a multimeter.

Do you have at least 2 frame grounds in the rear?

Yes i have 1 1/0 ground to frame on the front batt and 2 1/0 grounds from the rear batts to the frame.