Stuck in Austin - How long will car run without an alternator?

RazorRacer · 08-31-2003, 02:55 PM

Hello all,

I need to drive 150 miles (hwy) on a full battery without an alternator. Can I make it?

My alternator died on my new 928S and I'm stuck here in Austin. There's a full 12volts on the battery. If I drive 150 miles without lights, radio, or a/c, do you think I can make it?

I might pick up a new battery at the Auto store just in case.

masraum · 08-31-2003, 03:00 PM

I doubt you'd make it, that's a long way. If you had points and carbs maybe, but I bet the injection ignition on the 928 is probably pretty power hungry. Maybe if you carry a second battery...

Good luck!

rennch · rennch's Garage

I'd say no..I just bought a new battery today, and didn't make it an hour in my 72 911. (With a fried alternator...don't ask how)

david914 · 08-31-2003, 03:53 PM

150 miles? It wouldn't last very lo--

Early_S_Man · 08-31-2003, 04:02 PM

New batteries have to be fully charged before use ... ESPECIALLY if you are trying to make it home on battery power alone. A 'surface charge' is all you have on brand-new batteries, otherwise, and as demonstrated, it won't last long!

Charge the battery for 2 - 4 hours at 15 - 20 Amps, and you will be able to drive 150 - 200 miles without A/C ...

RazorRacer · 08-31-2003, 04:09 PM

Early_S_Man,

How nice of you to reply. It's been a long time.

It's a new battery, but not brand new. The alternator went out as I was trying to scalp some tickets for the UT vs. NMS game.

But's that's great advice, because I was planning on buying a new battery in case I don't make it.

Still...it's 3 who say I can't make it and you, who I have the most respect.

Will drivinig faster improve my chances?

GrindingGears · 08-31-2003, 04:19 PM

I say buy a battery and go for it! Let's see if it can be done.

-Grind

rennch · rennch's Garage

Ok...didn't work for me, but maybe you'll have better luck than I did!

Have fun!

RazorRacer · 08-31-2003, 04:30 PM

The battery in the 928S is huge. It's about 50% bigger than a 911 battery. This could be fun if the BBS gets behind me.

My sister reminded me that it could be raining and I will need the windshield wipers. At a minimum, I will get a spare battery and a battery charger.

Adman · 08-31-2003, 05:17 PM

Quote:

Originally posted by RazorRacer
My sister reminded me that it could be raining and I will need the windshield wipers. At a minimum, I will get a spare battery and a battery charger.

RainX the heck out of the windshield and with the 928 rake you should be fine. The closer you get to home the cheaper the wrecker if it comes to that. Good Luck!

pwd72s · 08-31-2003, 07:26 PM

My silly question? What's wrong with hanging out with your sister until you get an alternator that...well, alternates!

350HP930 · 08-31-2003, 07:30 PM

I would be suprised if even a fully charged battery could support the fuel pump, injectors and ignition for even an hour. If you have a multi-meter you can measure you basic running amperage and do some math using your battery capacity to make sure.

Perhaps if you driver really, really fast you might make it.

Adam · Adam's Garage

"Uh, Officer... my mechanic told me to drive at 150mph in order to get home before the battery died..."

Go for it! I did it once in an old Volvo (not as complex as the 928). It'll be an adventure you can look back on and smile.

RazorRacer · 08-31-2003, 08:04 PM

Adman, add RainX to the shopping list.
pwd72s, I have to get by boys back to do their homework...but I could put them on a bus.
350HP930, so driving faster helps...humm...and I didn't consider the fuel pump.
Adam, I love a good adventure.

David · David's Garage

Craig,

I'd offer to bring you a battery, but I don't think it'd help much. I'd go as far as you can and call a wrecker. Negotiate price before he touches your car, it's too late after that. If there is something I can do, feel free to call, don't mind the time: David

isaacyoon · 09-01-2003, 11:06 AM

well, did you make it?

RazorRacer · 09-01-2003, 12:03 PM

Oh yeah! Oh yeah!

I left Austin today at 12:20PM and made it to my house at 2:40PM. The voltmeter started at 11.75V and dropped to 11.5V by the time I got home. The voltage redline is at 10.25V. Again, this is a 928, not a 911.

I know the voltmeter is working because everytime I stepped on my brakes, it would drop to 11.0V. Total distance was 144 miles. I used the brakes about 40 times.

I know the alternator broke because a warning light appeared yesterday and then revving the engine didn't increase the voltage. Also, the alternator has been replaced twice in the last month (fortunately at the expense of the PO).

Think I can make it to my wrench tomorrow?

mjshira · 09-01-2003, 12:07 PM

I had this happen to me in Waco and I ran out of juice about the time I hit 75 in Dallas. If you go in the day time you might make it a 100 miles but I wouldn't chance it.

Adman · 09-01-2003, 12:11 PM

Craig....Alright! You Da Man! Dont need no stinkin alternator!

Now we all know you can make it 144 miles without a charging system. Now go out and run the car till it dies so we will know just how far you could have driven.

New data for the Pelican Technical files.

masraum · 09-01-2003, 01:16 PM

Awesome!! Congrats on making it. Now to fix or replace that alternator.