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CplCuddles

New Alt, Low Voltage issues

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Hey guys I'm back again with another issue,

 

I recently bought a 320 Amp Elite Series Alternator for GM Truck. I was having dropping voltages into the 10s when I decided to buy a HO alt. I replaced my 130amp stock alt with the Mechman and left on my default belt to start. I then started having low voltage at idle issues.

 

My Tahoe idles at 500rpm, I'm told this is low, but it has done it since the day I bought it, no issues until now. My initial problem was that when idling (500rpm) I would drop into the high 10s when playing music. I tried to put on a smaller belt as I have seen that is recommended for the smaller pulley, I could not get a smaller belt to fit (even tried 1/2 inch shorter belt, it would barely not fit), So I have the original serpentine belt still on, it seems to be plenty tight. Figuring it was my batterys charge that was the issue, I bought a 750Mah trickle charger and left it on the battery overnight.

 

This solved the low voltage at idle issue, initially. A few days later on the 4th of July I had the key on and the stereo on low and my voltages were saying 10V dropping into 9.5V, somehow I turned on my Tahoe and it jumped back up to 14.7V. The next day I couldn't start my Tahoe and had to get it jumped, same voltage issue as the day before. I took my Redtop to O'Reilly to get it load tested, and it came out fine according to them.

 

Then yesterday a new problem emerged, while driving I noticed my rpms dropping below 500rpm. I let off the gas and let it drop to see how low it would go and it dropped to about 200rpm and all my lights dimmed out almost completely. I parked and revved for a minute and then turned it off (I was going inside) and it rested at 10.2V immediately after turning my Tahoe off. The low voltage issue seems to be somewhat intermittent was this point. My father who is a mechanic is adamant that it MUST be the alternator. Does this sound like something may be defective with the alternator I received or what else may be causing this? Thanks!


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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Just stop and burn it down. A v8 that idles 500? Do understand that pulley rotation speed directly effects amperage output. Serious, just stop.


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Turn down your gains and go get your engine checked. You're having serious issues.

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Just stop and burn it down. A v8 that idles 500? Do understand that pulley rotation speed directly effects amperage output. Serious, just stop.

 

Gotta push through my dude. I do understand that pulley rotation directly affects amp output. I figure since the engine is having low rpm issues, that would be causing my voltages issues. People around me keep disagreeing and saying its prob my alt. I'm not a mechanic... at all.

 

Turn down your gains and go get your engine checked. You're having serious issues.

 

This is happening even without music, this all started after putting in my new Alt. Gonna get my codes checked tomorrow and see what comes up.


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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Gotta push through? I just hope your dumb*ss doesn't cause an accident when your sh*t breaks down.


Team Bang Hard Ohio Chapter

2013 Subaru Legacy B-Pillar

4 Crossfire v4 18s

4 Crossfire 4k's

2 Crossfire 2000.4s with Ampere JM1 Dsp

3 SINGER 270's + MI Solar 115ah 18v + 16.5ah 12v x2

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Just put your old alternator back on and see if the problem goes away.

 

 

Sent from my iPhone using Tapatalk

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Gotta push through? I just hope your dumb*ss doesn't cause an accident when your sh*t breaks down.

 

I don't understand what you're so perturbed about. That it idles at 500rpm? as I said it has always done that. That actually seems to be normal with my vehicle as well as vehicles of the similar type.

 

Just put your old alternator back on and see if the problem goes away.

 

 

Sent from my iPhone using Tapatalk

 

I'll probably try this, just a pita.


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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I don't understand what you're so perturbed about. That it idles at 500rpm? as I said it has always done that. That actually seems to be normal with my vehicle as well as vehicles of the similar type.

 

 

 

I'll probably try this, just a pita.

 

I have a 14 sierra and it idles at 500 rpms. In thinking of getting a new alt built but **** seeing **** like this makes me not want to. $400 down the drain.

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I have a 14 sierra and it idles at 500 rpms. In thinking of getting a new alt built but **** seeing **** like this makes me not want to. $400 down the drain.

 

The way I think about it is that its only a problem if I'm idle for long periods of time and pulling more than I am producing. On average I'm not full volume bassing every time I drive, so I'm really only pulling from reserve during downtime like stoplights. Which I figure if I get a nice reserve bank that won't be a problem at all, because the alt recharges the reserve while I'm not consuming more than produced. I'm not sure that it is the alt that is the actual issue here. Hence why I'm here :(


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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" somehow I turned on my Tahoe and it jumped back up to 14.7V"

 

So, when its running above idle, it reads 14.7v ?? (14.4 to 14.8v is pretty std charging voltage for that series alt. on a GM.) If so, it's probably not a defective alternator. 500rpm is low. 700-900 is std idle speed for that vehicle. Id look into that.


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" somehow I turned on my Tahoe and it jumped back up to 14.7V"

 

So, when its running above idle, it reads 14.7v ?? (14.4 to 14.8v is pretty std charging voltage for that series alt. on a GM.) If so, it's probably not a defective alternator. 500rpm is low. 700-900 is std idle speed for that vehicle. Id look into that.

 

Correct, If it above about 600rpm it shows perfect voltages. From what I've seen online 500-750rpm seems to be normal. I mean if it truly isn't normal will get it looked into, because it's kind of a pain to have this HO alt and I have idle issues.. lame.


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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Get a smaller pulley. The alt sounds like it's turning so slowly that it's not making any power. You can also adjust your engine idle speed maybe

 

does your vehicle have a throttle body with a cable from the pedal?

 

---------- Post added at 11:11 AM ---------- Previous post was at 11:10 AM ----------

 

What year vehicle?


buck.box.designs@gmail.com

I help with full system support, if you need advice

:yumyum: I just like making people happy :yumyum:

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Get a smaller pulley. The alt sounds like it's turning so slowly that it's not making any power. You can also adjust your engine idle speed maybe

 

does your vehicle have a throttle body with a cable from the pedal?

 

---------- Post added at 11:11 AM ---------- Previous post was at 11:10 AM ----------

 

What year vehicle?

 

It does make plenty of power at 600+rpm, it's seems that it's the low idle that is the issue. I honestly don't know about the throttle body, 2002 is the year.


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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Idk if you'd want to do this, you probably either need to raise your engine idle or get a slightly smaller pulley. I would contact the alt manufacturer and see what they recommend.

 

---------- Post added at 11:29 AM ---------- Previous post was at 11:29 AM ----------

 

You don't want to overspin your alt at higher rpms


buck.box.designs@gmail.com

I help with full system support, if you need advice

:yumyum: I just like making people happy :yumyum:

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Red tops are starting only batteries and aren't designed for sustained current draw. Sounds like the alt is defective tho.


giphy.gif

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Idk if you'd want to do this, you probably either need to raise your engine idle or get a slightly smaller pulley. I would contact the alt manufacturer and see what they recommend.

 

---------- Post added at 11:29 AM ---------- Previous post was at 11:29 AM ----------

 

You don't want to overspin your alt at higher rpms

 

They recommend a 1/2 smaller belt, it already has a smaller pulley than my stock did. I'm not entirely sure what "overspinning" an alt is.

 

Red tops are starting only batteries and aren't designed for sustained current draw. Sounds like the alt is defective tho.

 

I mean, it's still an AGM though, isn't an AGM an AGM or am I mistaken?


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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They recommend a 1/2 smaller belt, it already has a smaller pulley than my stock did. I'm not entirely sure what "overspinning" an alt is.

 

 

 

I mean, it's still an AGM though, isn't an AGM an AGM or am I mistaken?

 

You are very mistaken.


giphy.gif

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You are very mistaken.

 

I've looked it up, I can't find something definitive between say the redtop and the yellowtop other than it says its meant for starting applications.. but why? do you happen to know?


02 Chevy Tahoe

Optima Yellowtop up front

Big 3

Mechman Elite 320 amp Alt

Kenwood X599

Crescendo Audio Symphony Coax's

Sundown Audio SAX 100.4 

*NEW* SCV 7500D, currently @4ohm.

Sundown Audio X 12v2 @ 29Hz

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I've looked it up, I can't find something definitive between say the redtop and the yellowtop other than it says its meant for starting applications.. but why? do you happen to know?

 

https://www.optimabatteries.com/en-us/support/battery-basics/compare-deep-cycle-vs-starter-battery

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I've looked it up, I can't find something definitive between say the redtop and the yellowtop other than it says its meant for starting applications.. but why? do you happen to know?

 

In a nutshell- Starting batteries are meant to give a short burst of high current to supply a starter for the purpose of turning over an engine. Deep cycle batteries are meant for running high powered electronics and are designed for sustained current draw and many discharge and recharge cycles. Pulling constant high current from a starting battery will overheat the thin plates inside which hurts immediate performance (insufficient voltage because it can't supply the current) as well as a shortened overall life of the battery.

 

You shouldn't even be using an Optima battery in the first place, they are absolute garbage to begin with.

Edited by THATpurpleKUSH

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