Alternators 2 VS Me... Nothing!

**69CamaroRacer** · 10-27-2005

Ok here we go again. I have been thrashing with the new alternator that I got. I have the wriing kit from Mad electric so I know everything is hooked up correctly. Now I just did a check on the alt and at 2000 rpms it is putting out 135 amp @ 12.54v and that was messured at the back of the alternator. The batt will not stay charged. I have tested the batt and it checks out good. When I am ideling the voltage is only 9-10 Volts. So let me here some Ideas?

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**kman67rsss** · 10-27-2005

do you have underdrive pulleys on it. it may not be spinning fast enough at idel to put out any power.

**69CamaroRacer** · 10-27-2005

yes i do have the march performance underdrive pully kit BUT it should still be putting out 14.45 Volts at RPM so that is why I am at a loss.

**rocketrod** · 10-27-2005

12.5V measured at the alternator and 9-10V at the battery is low. Is the battery mounted in the trunk? What alternator are you using? Does it have an internal voltage regulator or are you still using the stock external voltage regulator? Is it a 1 wire alt?

**69CamaroRacer** · 10-27-2005

Originally Posted by rocketrod

12.5V measured at the alternator and 9-10V at the battery is low. Is the battery mounted in the trunk? What alternator are you using? Does it have an internal voltage regulator or are you still using the stock external voltage regulator? Is it a 1 wire alt?

Battery is in it's stock location, it is a red top Ultima. The Alt is an 180 amp CS style that has an internal voltage reg. It is not a 1 wire just a 2 wire CS.

**gmachinz** · 10-30-2005

Sounds like a bad voltage regulator to me. What brand of alternator do you have? I build custom alternators upwards of 200 amps but anything over 140 I usually have to mount diodes on the outside and build a dedicated enclosure for it-this is using a 6" case, too btw. -Jabin

**69CamaroRacer** · 10-30-2005

I had this one built by a shop here in town.... Tomarrow I am gonna have to go talk with them again.. I think I have 2 things going against me 1. Maby a bad voltage regulator. 2 is a set of under drive pulleys. Still at idle I thik i should have at least 13.8-14.2 Volts. The car idles at 1000 rpm and i think that if everything was functioning properly I would not have any problems

**gmachinz** · 10-31-2005

Under drive pulleys can keep the amperage output low but the volts should be over 14V-even with the car off it will read over over 12 volts.

**gmachinz** · 11-15-2005

any updates? Round 3 perhaps? lol

**Y-TRY** · 11-15-2005

I have been fighting an electrical gremlin in mine. There were several independent problems but I went through one-by-one and got it running (for now). I highly recommend checking out the "Remote Voltage Sensing" article on the MAD site.

Also- I found that it is important to have an alternator that makes good power at low rpm. Especially with underdriven pullies. Not all 140 amp alernators are the same. I was having a problem with my system pretty much dying when my fan came on at idle. It would pretty much kill everything. I have a Mark VIII with 70 amp relay. Turned out that the alt.I had made only 15amps at idle. So I stepped up to a Powermaster that makes 98 amps at idle and problem was solved.

Another thing I had to do was bump my idle speed up, because of the pullies. I have to keep it around 1050rpm to make up for the pullies and still charge at idle.

**69CamaroRacer** · 11-15-2005

Originally Posted by gmachinz

any updates? Round 3 perhaps? lol

You wanted an update so here goes.. In the endless persuit to get a functioning electrical sys i have up graded the charging system from Mad electrical. That helpped out some.. then I went and called march and ordered the smallest pully that they have. I think that it measures just under 2in. That made the alt start charging at about 1000 rpms but since i let her idle at 800rpm it is just a little lite. The next thing that I found was that I had a bad battrie so I took the Optmia back to Advanced and got a new one.. now I am about 99% sure that it will start every time as it looks to be charging most of the time. I do still see some low voltage readings with the fans and headlights on it will go to 12.5-13.5. but jumps to 14 if I turn the light off.... I say most of the time because I have noticed some weird things happeneing while crusing. My gagues tend to like to dance around like they are getting electrical surges and today my stock fuel gague decided to have a mind of it's own. It was on E so i decided to fill the tank and well it only took 8 gal so I knew that there must have been some fuel in the tank. When I filled it it did not go to F but stayed on E and then did a little dance between E Half and F for the next 5 min or so... Wierd like i said.. after that it went to F and stayed there and started to register like normal. I think that I may be haveing some grounding issues so that is where I am gonna try next.

**EVO** · 11-15-2005

Check your engine to chassis ground strap and body to frame ground strap. If the bolts/screws are a little loose, it will cause the problems you described.
Evan Q.

**69CamaroRacer** · 11-15-2005

Originally Posted by EVO

Check your engine to chassis ground strap and body to frame ground strap. If the bolts/screws are a little loose, it will cause the problems you described.
Evan Q.

I think that I need to install said grounding straps..... I only have one from the block to the subframe

**gmachinz** · 11-17-2005

Ah, yes-you need more grounds for sure! You need it from battery to chassis, body to frame and body to engine (two here...). Y-try, you should look into getting a controller for your car vs. using a relay for the fan. It would allow you to remove the relay and keep your system charging at a more practical ilde speed. Email me if you have questions and I can explain in detail how they work. After using several of them by now on my own cars, I will never go back to a relay activated cooling fan. Jabin

**CarlC** · 11-18-2005

Mine also would loose 150 RMP at idle when the Mark VIII fan came on. Had to run the idle higher than I would have liked so it would not die.

Now with the DC Controls fan speed controller the idle issue is gone. Rarely does the fan go to full speed, so there is less load on the alternator.

I'm trying to stick with a deep groove pulley for higher RPM on-track reliabilty. There have been no battery charging issues.

**gmachinz** · 11-19-2005

Carl, that's good to know. I used to run a 5" Moroso deep groove pulley several years ago but I didn't like the slow alternator speed as a result. I thought about putting it back on now to see what would happen...too many projects ya know...lol. Anyway, what diameter is your pulley? I'm getting the absolute MOST of of my charging system in terms of minimal voltage drop and current management-I use a max. of about 80 amps with a combination of controllers and some relays. With 140 amps on tap, I'm okay. Have you measured your total amp draw? What accessories are you running? -Jabin

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Alternators 2 VS Me... Nothing!