Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans Advertise
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Electrical> Alternator Issue
User Name
Password
lost password?   |   register now

Thread: Alternator Issue Reply to Thread
Title:
  
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Insurance
Please select your insurance company (Optional)

Log-in


Additional Options
Miscellaneous Options

Topic Review (Newest First)
07-05-2018 03:56 PM
36 sedan JMHO, do yourself a favor and run a #4 ground wire to the alternator from your bell housing or wherever your ground junction on the motor is, you really don't want all that current flowing back to the alternator through your motor parts.
07-05-2018 10:46 AM
tools
Problem Solved

Thank you all for your help. After trying everything and no results I thought it had to be the alt. wire itself. I contacted the harness manufacturer and they told me the harness wasn't made for a 100 amp alt. If you run a high output alt. you have to run a 4 Gauge wire from the alt. to the starter . I did that and it works just fine. With everything on cooling fan, A/C, lights, blower on high and radio it only drops to 13.5 to 13.8 .
06-22-2018 05:09 PM
BogiesAnnex1 In my case I'm running a 120 amp alternator. It just doesn't put out when it warms up, the battery is in great shape so in traffic just running the ignition it is hard to see if the alternator is producing anything because the ignition just isn't a big drain.

But turn the fans on and you can see the discharge rate start to pull the battery down. And that is a drop that can be seen as staying there when the fans are shut off, not all of it but enough to see on the gauge.

Bogie
06-20-2018 02:29 PM
'49 Ford Coupe For what it's worth, my 35 amp output alternator could not keep up with electric fans, A/C, power amp, and headlights, fresh air fan, etc.,, so after some research I got a chrome Proform 100 amp single wire (comes with a factory output test chart) from Advance Auto Parts and, BOOM, all electrical problems disappeared. Instant charging from the moment of startup, stable output. Just my two cents.
06-20-2018 01:31 PM
BogiesAnnex1
Quote:
Originally Posted by rip-tide View Post
That is exactly what the problem is with the one wire set up. I say it a thousand times. One wire is for lawn mowers, tractors and gas powered welder type of operational conditions.


It is easily seen when a car is using the one wire deal. When looking at a line of cars stopped, the car with the dim & yellow head lights is the 1 wire set up. Three wire has the same intensity no matter what the RPM.

I not going to bother explaining the why, cause it has been over and over and over.

You will never have the problem with the 3 wire set up....... you're certainly free to ignore the advise.
pep
I probably didn't state this right. The problem is temperature related, getting into city traffic is a coincidence. With cold startup even at idle the output has a line voltage of 14.5. Then traveling on the interstate the voltage tapers as you'd expect but falls to 12 all the while the engine compartment is heating up as the engine reaches its 195 operating temp. Since it's summer there is nothing the electrical system has to feed on the highway other than the ignition, no AC, no stereo, no lights. This condition never relates to RPM and for now is survivable. Winter with dark when I leave and dark when I return and dim all day long requires running with lights and defroster so the battery alone will not keep up with this constant load of this condition with the alternator persists.

Currently, this being summer, when I get off the super slab to go into the big city I have to turn the cooling fans on. When that happens the voltage just slips away with no regard for engine RPM. But they only need to run for 15 to 20 minutes not all the time like the winter electrical loads.

Once the engine cools with a gauge reading of less than 195 the alternator is putting out 14.5 following start up. That lasts till the temp gauge hits 195 then back to no output regardless of RPM. This cycle just repeats through the day. The battery is obviously in good shape as for the few minutes it gets a full charge rate it keeps up with the demand of cranking the engine as needed without having to connect it to a charger. But that won't last forever.

This is the second or third GM one wire that has died in this exact same way in about as many years. So I expect that there is some generic fault in these things, perhaps given the mileage I put on in a year they just wear out in this time frame. I'm not researching this any deeper than an afternoon R&R job; but I am going back to the older three wire configuration simply because my history with those is they lasted longer. But as time and the industry mantra of "faster, better, cheaper" (with emphasis on faster and cheaper so 2 outta 3 ain't bad) continues it just might be that anything today just doesn't hold up to my expectations.

Bogie
06-20-2018 11:44 AM
ogre
Quote:
Originally Posted by tools View Post
The alternator is grounded to the block. I have the battery in the trunk and grounded to the frame. Positive cable goes directly to starter where it connects to alternator wire.
possible that you need a ground wire from frame to engine
i too am a fan of the 1 wire alternator and suggest you keep a spare diode pack and regulator on hand
buy the good diode pack, i forget what the nomenclature is but it's made for the 100-140 apm alt
i believe eod guy helped me out when i went thru 2 oreillys rebuilds in as many weeks
i now keep spares with me on long runs, i can replace parts in a few minutes
06-20-2018 07:16 AM
rip-tide Think of the exciter wire as the pressure regulator on a compressor. It's job is to recover the air that has been used, before it is all gone. That's the best analogy, and describes what's happening. In spite of what some think the car runs off the battery, not the alt.

Also tells you why a car with one wire willie, has the dim lights. Again using the air compressor as the comparison. Compressor will run continuously if the demand is high. Pump get hot, tool has less torque, performance is degraded.

Same deal happening, as the alt tries to recover the battery loss. And because AMPs are HEAT ...... well 2+2 = hot alt. With solid state devices shutting down, if not going offline completely, out put is degraded .

Cheers,
pep
06-19-2018 04:12 PM
EOD Guy I thought it was something new.....

You can make just about any three wire into a one wire by hooking in a jumper wire (I've never had to use a diode). In a true one wire this is done internally.

Once a one wire receives enough output from the charge lug to excite the field it will start putting out juice and to my knowledge will continue to produce juice until the alt stops spinning. The difference is...… you need higher RPMs initially to get the alt to start producing juice, once it starts producing it works about the same as a three wire.


IMO the drawback is...…. the sense wire is taking the reading from the charge lug, which isn't the ideal place to get a sense of the demand/draw on the electrical system. The three wire OEM setup allows the sense wire gets it's reading further down the line and a truer demand/draw on the electrical system.

Both work just fine.
06-19-2018 01:09 PM
JeffB28 Guess we are digging up "old bones" again. https://www.hotrodders.com/forum/one-...or-272721.html
06-19-2018 12:32 PM
JeffB28
Quote:
Originally Posted by EOD Guy View Post
Please explain how "adding a simple diode to your one wire alternator it will excite early and full charge at low RPM's"


Very curious as how that would happen.
I was having an alternator tested and he made the jumper up for me ask them for details here: Contact Us - GEN-STAR ELECTRIC This shows output at idle because of the low mounting of the alternator I could not get a shot of the wire & diode which converts the 1 wire to a "2 wire"
06-18-2018 04:26 PM
EOD Guy Please explain how "adding a simple diode to your one wire alternator it will excite early and full charge at low RPM's"


Very curious as how that would happen.
06-18-2018 02:04 PM
JeffB28 By adding a simple diode to your one wire alternator it will excite early and full charge at low RPM's.
06-18-2018 07:42 AM
fat tire I have had a one wire alternator on this rig for 20 years with no problems.
head lights, plow lights, amber flashing, beacon light, heater and radio
06-18-2018 07:20 AM
rip-tide
Quote:
Originally Posted by BogiesAnnex1 View Post
It will hold 12 volts with the engine turning 2000 RPM but as soon as I hit city stop and go traffic and the cooling fans come on the voltage drops under 12. So I think I'll be shopping for a replacement before too long.

Bogie

That is exactly what the problem is with the one wire set up. I say it a thousand times. One wire is for lawn mowers, tractors and gas powered welder type of operational conditions.


It is easily seen when a car is using the one wire deal. When looking at a line of cars stopped, the car with the dim & yellow head lights is the 1 wire set up. Three wire has the same intensity no matter what the RPM.

I not going to bother explaining the why, cause it has been over and over and over.

You will never have the problem with the 3 wire set up....... you're certainly free to ignore the advise.

pep
06-18-2018 03:12 AM
JeffB28 Sometimes guys use too light a gauge feed wire I've always used a 6 gauge battery cable from the alternator to the positive battery terminal and never had issues even with A/C,electric fan and electric fuel pump, check out this article: https://www.tuffstuffperformance.com...structions.pdf
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -6. The time now is 04:11 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.