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Question on alternator output

 
Old 07-10-2019, 02:39 PM
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worcestervette
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Default Question on alternator output

Had a P0622 code. Checked the battery and replaced it as it was 4 years old. Found the nut on the starter loose by about 3/4 turn. Tightened that. Everything was great. Idle was about 13.8 volts at idle and up to 14.2-14.5 volts while driving.

Today, while sitting in the parking garage with the AC blasting I put the top up and noticed it dropped down to about 11.5 volts momentarily.

I guess I am now paranoid. I need reliability. Time for a new alternator?
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Old 07-10-2019, 10:47 PM
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Silver c6 z-51
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I had the same issue and was seeing a service charging system on my DIC. Changed to a Mechman alternator and the problem disappeared as the alternator puts out a constant 14.5 V all the time.
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Old 07-11-2019, 12:39 AM
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jonjoy
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I went with a power master and saved $ as opposed to the mechman 15 volts at the alt at idle
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Old 07-11-2019, 05:24 PM
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hrt vlv
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Check voltage on cabled and on battery, is there any voltage drop? that little ramp piece on cable clamp broke on mine. causing this voltage drop because of cable being loose. I only found out later that the ramp piece is available after replacing cable. It could also be corrosion of cable not visible to you.Also check alternator output.
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Old 07-12-2019, 09:59 AM
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worcestervette
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All cables are tight. Everything was checked when I replaced the battery and CKS. Everything is super clean and no corrosion present, even on the ground cables.

It seems that when several high demand accessories are used the alternator output drops.

I ordered a new alternator. I enjoy working on the car and I need it to be 100% reliable because my daily work commute is 100 miles and I don't need any hassle regarding a no start issue
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Old 07-12-2019, 10:16 AM
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LS WON
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Is there an optional higher output alternator for the Corvette?
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Old 07-12-2019, 12:32 PM
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Originally Posted by LS WON View Post
Is there an optional higher output alternator for the Corvette?
There are a few options. I just bought a 240 amp Mechman alternator to drive some of my power hungry gear.
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Old 07-12-2019, 01:07 PM
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wayback
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Originally Posted by worcestervette View Post
All cables are tight. Everything was checked when I replaced the battery and CKS. Everything is super clean and no corrosion present, even on the ground cables.

It seems that when several high demand accessories are used the alternator output drops.

I ordered a new alternator. I enjoy working on the car and I need it to be 100% reliable because my daily work commute is 100 miles and I don't need any hassle regarding a no start issue
If this drop happens at idle while several high demand accessories are used it is normal for the OEM Alt.

I agree with changing to a Mecman......I went with the 170 A unit and no more low V situations.
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Old 07-12-2019, 01:26 PM
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RobLo
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Originally Posted by wayback View Post
If this drop happens at idle while several high demand accessories are used it is normal for the OEM Alt.
Had mine out recently in 90*+ weather with A/C on full plus the radio, at idle it occasionally dropped to 11.9, 11.7, car would shudder a bit at idle but output would come back to 13.2, 13.3 while underway. I ALWAYS keep a Tender on the car when not in use so battery is always fully charged. About a year ago I had the same condition so I pulled the alternator and took it to an electrical repair shop, one of only a few around that still does repairs. He bench tested it and said it was working fine and that these alternators usually last about 75K miles. So I stopped monitoring the DIC for output and solved the problem, if it gets dangerously low I'm sure there'll be plenty of lights and sounds to let me know something is wrong.
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Old 07-12-2019, 06:55 PM
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Originally Posted by doomi View Post
There are a few options. I just bought a 240 amp Mechman alternator to drive some of my power hungry gear.
Does it fit right in Corvette with no modifications?
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Old 07-12-2019, 11:57 PM
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Originally Posted by LS WON View Post
Does it fit right in Corvette with no modifications?
It drops right in.
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Old 07-13-2019, 03:53 AM
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LS WON
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Originally Posted by doomi View Post
It drops right in.
Where did you get this from and cost? I wonder what is the rating of standard 2005 Corvette alternator?
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Old 07-13-2019, 11:25 AM
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Originally Posted by LS WON View Post
Where did you get this from and cost? I wonder what is the rating of standard 2005 Corvette alternator?
I bought it on ebay because that's the only place that had it in stock. I paid about $600.You can order straight from Mechman a bit cheaper, but they are made to order and I didn't want to wait.

Your 05 would be 110 amp out of the factory. They moved to a 140 amp oem alternator in later years.
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Old 07-13-2019, 11:42 AM
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Old 07-13-2019, 04:41 PM
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Originally Posted by Silver c6 z-51 View Post
I had the same issue and was seeing a service charging system on my DIC. Changed to a Mechman alternator and the problem disappeared as the alternator puts out a constant 14.5 V all the time.

Normal, since the OEM Valeo 160amp alternator only puts out about 16 amps at idle. So when you have the A/C on, it turns the raditor fan on that is drawing about 16amps itself, and the other part so the car drawing amps put the battery into a draw state. As soon as you get going again (rpm increases), then alterntor puts out more amperage and will catch up with the total car needs, and recharge the slightly drained battery.

As for better alternator, it's a 6 phase unit over the 3 phase of the stock alternator, which will put out about 60 amp when the car is idling isntead.

The billet 6 phase alternators can be found here. And again, not what the alternator can put out when fully spun up, but what ampere that the alternator can put out when the RPMS is only 600 instead.

https://www.corvetteforum.com/forums...w-pricing.html

Last edited by Dano523; 07-13-2019 at 04:42 PM.
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Old 07-14-2019, 06:35 PM
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Originally Posted by Sox-Fan View Post
So will this place install this wiring kit and a heavy duty alternator on Corvette? Or do they just sell products?
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Old 07-14-2019, 08:24 PM
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I'm in South Carolina. l have no idea if they do installs as I am rather far away to think about having them do it. Call them and ask. Or better yet, do it yourself. It's not hard, you don't need to lift the car and use any special tools.
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Old 07-14-2019, 08:46 PM
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Originally Posted by Sox-Fan View Post
I'm in South Carolina. l have no idea if they do installs as I am rather far away to think about having them do it. Call them and ask. Or better yet, do it yourself. It's not hard, you don't need to lift the car and use any special tools.
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Old 07-16-2019, 03:09 PM
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hrt vlv
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Even though it is regulated, can you have to much output causing premature battery failure? What is the output of a mechman when it is up to speed?
With the high output is a larger gauge wire required or suggested from the alternator to battery?
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Old 07-16-2019, 03:53 PM
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Originally Posted by hrt vlv View Post
Even though it is regulated, can you have to much output causing premature battery failure? What is the output of a mechman when it is up to speed?
With the high output is a larger gauge wire required or suggested from the alternator to battery?
Think of amperes as being "pulled" by a load. If there is little or no load, then amp output is little to none. The service in your house is the same. Amps are a capacity of electricity, sitting there, waiting to be used. Turn a lamp on, and your 200 amp service gives it one amp or so, the other 199 are waiting in reserve.

As for the wire, I don't know, but I've not heard anyone mention having to do that.
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