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-   -   how far can a car go without an alternator? (https://forums.maxperformanceinc.com/forums/showthread.php?t=881821)

tdavidl 08-25-2025 07:14 PM

how far can a car go without an alternator?
 
have my 71 fbird scheduled to go into the shop this wednesday...a few weeks ago i realized my alternator crapped out and isn't charging the battery or providing power to the components that need power. shop is 15-20 minutes away, 6-7 miles...so the question is:

assuming everything is turned off and the only things needing power are brake lights, blinker lights & of course, the spark plugs...how far will a two month old fully charged battery take it? can the battery power the car for the 15-20 minute drive?

Formulabruce 08-25-2025 08:04 PM

Charge battery and go for it. Changing an alternator isn't a hig job though.. if yours is an original " 928" I would hang on to it.

tdavidl 08-25-2025 08:17 PM

thx...scheduled a complete car re-wire several months ago...i'm ready to replace the 55 yr old wiring...alternator just happened to crap out and they apparently plug in a new alternator as part of the re-wire job...they know i want all original components back...even the old wiring in case there are any connectors i can save for someone else...

poncho-mike 08-25-2025 10:52 PM

They can go further than you think.

I bought a car in northern GA and trailered it home with my 1978 Sububan 2500. About an hour after picking up the car, my alternator light came on. I was still about two and a half hours from home, and had only about one hour of daylight left. I was on the interstate, so I disconnected my trailer wiring, unplugged one of my headlights, and went for it. When it started getting dark, I turned on my lights (with only one headlight). I noticed them getting dimmer just before I got to Charlotte, so I stopped at my uncle's house in west Charlotte. He had a motor home, and loaned me the battery out of it to help me get home. I left the car & car trailer at his house. Before leaving for the last leg of the trip, we put his battery on charge for about an hour. I left my battery there and headed for home (with one headlight unplugged). I made it home no problems. I re-clocked an old Pontiac alternator, and it worked. I went back and picked up the car & car trailer. This was around the late 1980s, and I was running a Diehard battery.

Jack Gifford 08-26-2025 01:03 AM

Yes, and much further- unless starter is used often.

tdavidl 08-26-2025 08:56 AM

thx jack

tdavidl 08-26-2025 09:00 AM

thx, good to know...i feel better knowing this...i'm sure i'll still worry a little as i drive watching the old volt gauge drop with each braking...

Bill Hanlon 08-26-2025 09:02 AM

In 1968 I lost the generator on my 1961 Mercury Comet at about 4 in the morning on a full moon night on I-45 about 40 miles north of home. I turned off the headlights (except when near other cars) and the heater and drove home. Made it without a problem.

srmmmm 08-26-2025 09:32 AM

In 1985, The front bearing failed in my alternator in my '70 Firebird as I was headed from OKC to Ohio on I-40 one night. Sparks everywhere for a minute until the belt came off. I drove for another 40 minutes with the headlights on to a real "service station" and parked there until it opened in the morning. Installed a new alternator and the car started right up. I was always running Die Hard Gold series batteries back then.

tdavidl 08-26-2025 01:14 PM

thx everyone...makes me feel better on my 15-20 minute drive w/only brake-blinker lights

Cammer-6 08-27-2025 10:57 AM

A buddy whos sometimes a lurker here,had an alt go out in his Mercedes many miles from home.
He stopped in autoparts store bought a new battery and drove it until is was used up then bought another battery.
He made it home with 3 dead batteries. IIRC that alt was about $500

tdavidl 08-28-2025 09:36 AM

that's funny...buying all kinds of batteries to get it home...for my update:

drove it the 15-20 minutes yesterday to the shop & volt meter hovered the entire way around 13 as it should..so what changed?

over the weekend when i pulled the battery after a short drive i noticed the small wire on the negative wire that connects to the battery post had come loose from the rad support so i re-attached it...so i'm thinking that had something to do with why the volt meter in my previous couple of drives was declining into the 10-11 volt range ...not grounded properly?

burd 08-28-2025 10:35 AM

Shave the alt for a cleaner look ?


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