alternator charging but battery flat after 1 mile


Asked by Jul 28, 2014 at 04:40 PM about the 1963 Ford Thunderbird

Question type: Maintenance & Repair

1963 thunderbird, the alternator is charging and has been checked as ok, it runs the car and can go up to 16 V when I rev, If I start the car with a fully charged battery ( on charge overnight) it runs ok but when I stop a couple of miles later it wont start again, no power.
I have a spare in the trunk and it starts fine on jump leads.
any ideas.
When I put a tester on the NEG post in between the NEG post and the NEG line I get a 12.67 V reading, start the engine , stop it again and I then get a 5.9V reading

5 Answers


First of all a voltage reading of 16 volts when you rev it is too high, the regulator should hold it at around 14.2 to 14.7 volts, voltage like that could fry things like instruments, lights batteries,etc. Did you have the battery checked for proper load capabilities? Make sure your cable connections are good on your battery and engine.

1 of 1 people found this helpful.

Thanks tenishoe ill check the regulator and see if I can set it 14.5 max then, if not ill get a new one, ill post the result neil


Tennisshoe thanks for the advise the regulator was adjusted and I turned it down at tbe moment ive left it at13V Im aware this is too low but im now investigating if the previous setting (which I tried at 4000 revs and went to 17.8) ) Was burning the battery hence not holding its charge for this ive put a different battery on.


You also need to have your battery checked for load. Go to any parts house like Auto Zone, Advance Auto, etc and they will check it for you and give you exact info on state of the battery. I had a similar problem and it turned out the battery was bad and it was running on the alternator.


Thanks oldtimer37, between you and tennis shoe I think Ive solved the problem. I had a new battery 1 year ago, then last week on tennis shoes advise I checked the regulator, sent to America for a new one fitted today, voltage now about right (14V) earth wiring checked, Alternator checked by garage and hey, ( battery burnt out) so it looks like the 16-18V on the faulty regulator was the culprit ( and costly) so ill get a new battery. 1 new battery 2 Checked alternator 3 new regulator 4 earth connects show no Voltage drop Thanks again, keep helping im nearly at the end of finding a faulty "knocking" from the front end, next week into the garage again for:- New link bar ( drag link) new inner and outer rod ends new shock absorber from US new shock lower mount Thanks Neil London UK

Your Answer


Looking for a Used Thunderbird in your area?

CarGurus has 1,097 nationwide Thunderbird listings starting at $6,950.


Ford Thunderbird Experts

  • #1
    Larry Sturgis
  • #2
    Tom Demyan
  • #3
View All

Related Models For Sale

Used Ford Mustang
744 Great Deals out of 42,182 listings starting at $1,300
Used Chevrolet Corvette
243 Great Deals out of 22,068 listings starting at $2,500
Used Mercedes-Benz SL-Class
52 Great Deals out of 2,711 listings starting at $3,950
Used Chevrolet Impala
577 Great Deals out of 34,588 listings starting at $1,250
Used Porsche 911
103 Great Deals out of 4,832 listings starting at $11,500

Used Cars For Sale

2005 Ford Thunderbird For Sale
83 listings starting at $9,500
2004 Ford Thunderbird For Sale
124 listings starting at $7,500
2003 Ford Thunderbird For Sale
4 Great Deals out of 157 listings starting at $9,487
2002 Ford Thunderbird For Sale
7 Great Deals out of 363 listings starting at $6,950

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.