Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 07-08-2018, 03:07 PM   #1
deetz
Junior Member
 
Join Date: Feb 2015
Location: State of Jefferson
Posts: 11
Default 6 volt generator output

Working on a '39 Mercury which doesn't hold a battery charge too well, and wondering what the generator output should be. Guessing around 7 volts? Thanks.
deetz is offline   Reply With Quote
Old 07-08-2018, 03:39 PM   #2
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 12,751
Default Re: 6 volt generator output

A little over 7 volts. Also need to check and see if anything is bleeding the battery down with the ignition off.
JSeery is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-08-2018, 04:31 PM   #3
Charlie Stephens
Senior Member
 
Join Date: May 2010
Location: Southern California
Posts: 6,078
Default Re: 6 volt generator output

Quote:
Originally Posted by deetz View Post
Working on a '39 Mercury which doesn't hold a battery charge too well, and wondering what the generator output should be. Guessing around 7 volts? Thanks.
I am not sure I understand the problem. Does it go down overnight? Does it go down when driving it like the generator isn't keeping up with the load?

Charlie Stephens
Charlie Stephens is offline   Reply With Quote
Old 07-08-2018, 04:50 PM   #4
deetz
Junior Member
 
Join Date: Feb 2015
Location: State of Jefferson
Posts: 11
Default Re: 6 volt generator output

I can jump-start it, and the engine starts and runs fine. Have never driven more than about 45 minutes. After initial start, I can get another start or two. After that, starter begins to turn over very slowly and petty soon kaput. Battery is about 10 years old (have not load tested yet). Generator belt and electrical connections are tight. Just poking around under the hood at this point.
deetz is offline   Reply With Quote
Old 07-08-2018, 04:55 PM   #5
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 4,804
Default Re: 6 volt generator output

If that battery ain't an Optima, you are seriously pushing your luck.
tubman is offline   Reply With Quote
Old 07-08-2018, 05:05 PM   #6
fordwife
Senior Member
 
Join Date: Dec 2015
Posts: 172
Default Re: 6 volt generator output

test the battery, 10 years is getting pretty old.
fordwife is offline   Reply With Quote
Old 07-08-2018, 05:36 PM   #7
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 9,992
Default Re: 6 volt generator output

10-years is well past any warranty period and most only have a max of 5-years. I never expect much more than that. I've looked for 6-volt high rate discharge testers and I don't think anyone make them any more. A volt meter and a hydrometer will tell you a lot. A good high rate test is to check it a night. Turn the head lights on and crank the starter. If the lights go way dim after it's been fully charged by a charger then the amp hour capacity is getting very low.

Your generator(should be a 2-brush with 3-pole voltage regulator on the 39 Merc) should put out 7.2 to 7.6-volts or there abouts. At the battery, it should give a volt reading above battery voltage when the engine is running with generator charging.
rotorwrench is offline   Reply With Quote
Old 07-08-2018, 08:58 PM   #8
fjz
Member
 
Join Date: Jul 2017
Location: Belleville, Ontario
Posts: 85
Default Re: 6 volt generator output

How do you check a generator?
fjz is offline   Reply With Quote
Old 07-10-2018, 10:43 AM   #9
jimvette59
Senior Member
 
jimvette59's Avatar
 
Join Date: Jun 2010
Location: Long Island NY
Posts: 879
Default Re: 6 volt generator output

fjz charge it and load test it.
jimvette59 is offline   Reply With Quote
Old 07-10-2018, 10:58 AM   #10
fjz
Member
 
Join Date: Jul 2017
Location: Belleville, Ontario
Posts: 85
Default Re: 6 volt generator output

Jim: How do I load test it? I have a volt meter. Thinking of Disconnecting the wires from the generator, starting the motor then touching the terminals with my volt meter. Will this tell me anything?
fjz is offline   Reply With Quote
Old 07-11-2018, 06:55 PM   #11
russcc
Senior Member
 
Join Date: May 2010
Posts: 2,109
Default Re: 6 volt generator output

Most good garages have a way load testing a battery. They charge it fully, and then put a load on it to measure it's condition. 10 years is a long time for an average battery, especially if it isn't used often.
russcc is offline   Reply With Quote
Old 07-11-2018, 07:10 PM   #12
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 12,751
Default Re: 6 volt generator output

Quote:
Originally Posted by fjz View Post
How do you check a generator?
Two recent Koats post:

A quick easy test on the generator only. Join the Gen and Field wires together at the regulator but have them disconnected from the regulator. Connect an analogue DC voltmeter to the two connected wires (NEG voltmeter wire) and the POSITIVE voltmeter wire to ground. This is assuming your Ford is original POS ground. The scale on your meter needs to be 20 to 30 volts DC. Start engine and rev it up to 2000 RPM or so and the voltmeter reading should rise quickly to the end of the scale as the revs rise. IF volts are zero or low as in 6 volts or so then the generator is faulty. Its a bit hard using a digital multimeter set to DC volts to read this. An old analogue type voltmeter is best. Just do that test ONLY and report results. Regards, Kevin.

Get your car hot and up to the point where it is not charging again, leave it running and disconnect the field wire, (middle one ) from the voltage regulator and move/connect it over to the Armature or Gen terminal. Rev engine up and read voltage at generator terminal of regulator which should go to 8 volts plus. This is providing the generator is Ok. We have bypassed the regulator field control here and the generator will charge flat out if it is working OK. If there is still a low voltage reading of 6.25 volts then the generator is faulty. If the voltage is 8 volts plus then the voltage regulator is faulty and requires attention. Also very important that all battery power connections and earths a good throughout the car. Check battery terminals, starter solenoid terminals, ammeter terminals, etc. Should be tight, clean and not getting hot to the touch during operation. Regards, Kevin.
JSeery is offline   Reply With Quote
Old 07-11-2018, 11:11 PM   #13
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN/FL
Posts: 4,764
Default Re: 6 volt generator output

Charlie and JSeery are hitting on all cylinder here on internet armchair ideas.


Of course if your battery is bad then.... autozone will check crank power for free, but they sell batterys . CCA are something to consider. I'd do the battery separate to isolate the issue.
Tinker is offline   Reply With Quote
Old 07-11-2018, 11:18 PM   #14
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN/FL
Posts: 4,764
Default Re: 6 volt generator output

Quote:
Originally Posted by fjz View Post
How do you check a generator?

Volt meter will tell if it's charging when running past 2rpm. A good apm or volt meter in the car is convent. Factory installed.


Along with a good oil pressure gauge, left right water temps and a decent fuel gauge. You can't go wrong. I've added a vacuum gauge just for fun.
Tinker is offline   Reply With Quote
Old 07-14-2018, 02:45 PM   #15
fjz
Member
 
Join Date: Jul 2017
Location: Belleville, Ontario
Posts: 85
Default Re: 6 volt generator output

Did the Koates generator test. Generator putting out 19.6 volts. Amp gauge reads -2 when running both with my old and new regulators. Took cover off the regulator and can not see anywhere to adjust. How can I check the regulator?
fjz is offline   Reply With Quote
Old 07-14-2018, 02:50 PM   #16
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 12,751
Default Re: 6 volt generator output

Regulators are not easy to adjust. I have an article on it I can post later.
JSeery is offline   Reply With Quote
Old 07-14-2018, 07:01 PM   #17
fjz
Member
 
Join Date: Jul 2017
Location: Belleville, Ontario
Posts: 85
Default Re: 6 volt generator output

Thanks JSeery. Looking forward to it.
fjz is offline   Reply With Quote
Old 07-14-2018, 09:38 PM   #18
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 12,751
Default Re: 6 volt generator output

This is not the one I was originally thinking of, but it might help give you the idea of what is involved.
Attached Images
File Type: jpg gen7a.jpg (70.1 KB, 39 views)
File Type: jpg gen8a.jpg (75.6 KB, 25 views)
Attached Files
File Type: pdf VR Booklet.pdf (1.43 MB, 15 views)

Last edited by JSeery; 07-14-2018 at 09:50 PM.
JSeery is offline   Reply With Quote
Old 07-15-2018, 12:34 PM   #19
fjz
Member
 
Join Date: Jul 2017
Location: Belleville, Ontario
Posts: 85
Default Re: 6 volt generator output

JSeery: Read the article. I am thinking my issue is that I have the ground wire connected to the cover and not under the mounting screw. Will install a separate ground later and try that. Thanks for your help. Frank
fjz is offline   Reply With Quote
Old 07-15-2018, 02:50 PM   #20
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 12,751
Default Re: 6 volt generator output

It depends on how the VR is mounted, if it is straight to the firewall with metal to metal contact it should be ok as is. If it has the rubber vibration washers then the ground wire needs to be connected to the firewall. I would make sure that both the VR housing and the generator are connected to a common ground near the VR and make sure that the body (firewall) has a good ground back to the battery.
JSeery is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 03:13 AM.