General Question

cubozoa's avatar

How long will my car run without the battery charging?

Asked by cubozoa (1198points) January 3rd, 2011

So, my car has died. Basically, the timing belt has snapped and the alternator is not working. The engine itself runs, but the battery will go flat, as it is not getting charged. I have it parked outside my flat and need to get it to a garage to get fixed. If I charge the battery up, how long will the battery last before the engine dies?

I should probably mention that it is a petrol (not diesel) engine. Oh, and I’ll turn off all the lights, a/c, heating, etc. I know this is quite an open ended question, as it obviously depends on the speed I’d be driving, but I really have no idea. Will it die almost immediately, or would it keep going for say 10 mins?

[...and yes, it serves me right for buying a french car.]

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12 Answers

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coffeenut's avatar

My old car did something like that….I could drive (depending on speed) 15–20 min on a full charge before it died….

tedd's avatar

It depends on the car, what electrical devices you have running in the car, and how well charged your battery is.

The last time my alternator went out my car made it about 30 minutes before it died, and every progressive jump only lasted 5ish minutes.

Meego's avatar

I remember I had a car with the belt gone, it was a lot of smoke! Anyway, my father had the car towed, to my knowledge without the belt you won’t go anywhere anyway I think your engine could seize, which could be more problems. But again I’m no mechanic and it has been a long time since I have had a car with no belt. The alternator is what keeps the charge to the battery which is why when it is faulty it will only hold the charge for a certain length of time. I have no clue though I’m not a mechanic.

LuckyGuy's avatar

I’ll assume your car was made in 2000 to 2005. The ECM and engine management system draws can draw about 200 Watts. That’s 8 Amps. If you have a new, fully charged battery that holds 42 Amp hours you can run as long as 5 hours. But you don’t. Your battery is probably old. Maybe you’re good for an hour. Try to get or borrow an inexpensive charger ~$15 and charge your battery. Then go for it.

By the way, it is not your timing belt that’s is broken It’s the alternator or accessory belt. If your timing belt is broken the car will not run at all.

filmfann's avatar

My experience here is with older cars.
With the alternator out, the battery will not only crank the engine to turn it on, but run all the electronics, and provide the spark to the spark plugs.
I don’t know how much electronics you have (the dashboard instruments, for example), but if you don’t have headlights that come on when you drive, and you don’t run the heater or wipers, you might get 25 miles, tops. My guess is 10 miles if you have those electronics.
Then, your battery will be dead, and the engine will not get a spark to the plugs.

cubozoa's avatar

@worriedguy Yes, sorry. I mean the alternator belt, not the timing belt.

RocketGuy's avatar

Perhaps you could go to the auto parts shop and get the appropriate belt, then ask the guy what you need to do. Last time I changed an alternator belt, I needed to mess with only 2 bolts.

jerv's avatar

Without an alternator, generally a few minutes at night and a few more during the day when you are not using your headlights with most modern cars. It depends a lot on how much load you place on the battery, but by the time your headlights dim, you generally don’t have long; maybe two minutes tops. A car with a carburetor will last considerably longer, especially if it also has a mechanical fuel pump.

Without a timing belt, about 0.07 seconds at best. Done that twice :P

cubozoa's avatar

Thanks for your help! My car successfully made it the 5 minute journey to the nearest garage. A relatively pain free journey, although the power steering wasn’t working.

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