How long to re-charge a flat battery

[sidicks]

As per my previous post about trickle chargers, the battery for my 911 (997) was flat the other day, so I needed to start the car with jump leads.

Leaving the engine idling, but with no radio, air con, lights etc etc how long will it take to get the battery charged up sufficiently so that it will be able to re-start the car?

Thanks

Sidicks

[thegoose]

It depends how flat it was (i.e. no lights on or anything working at all to turning over too slow to start, or anything in between) and the condition of the battery but for a decent battery that wasn't too flat (i.e electrics were still working, but starter wouldn't turn/enough) 15-20 minutes is often enough - that won't fully charge it, but will put enough charge in to re-start it.

[sidicks]

The lights and electrics were operating, but when the key was turned, jut a clicking sound and no sign of the engine even attempting to splutter into life.

After jump starting the car, I went for a 30 minute drive, then left it idling for an hour and then went for a spirited drive for another hour.

When I got home, I tried to restart the car - absolutely nothing, just as before. I can only assume that either my battery is f*cked or my alternator is.

I presume that the alternator would be covered under Porsche warranty, whereas the battery isn't?

Cheers

Sidicks

FWIW: My car is an '06 997 C4S and I extended the warranty when it ran out in March '08. I wouldn't have expected the battery to fail after just 2-3 years and 15,000 miles....

Edited by sidicks on Sunday 11th January 17:44

[HAB]

If it was so drained that it wouldn't even turn the starter over, you'll probably need to remove it and charge it overnight.

Edited by HAB on Sunday 11th January 17:44

[sidicks]

HAB said:

If it was so drained that it wouldn't even turn the starter over, you'll probably need to remove it and charge it overnight.

Edited by HAB on Sunday 11th January 17:44

Surely after driving it for 1.5 hours and letting it idle for another 1 hour+, I should expect at least a spark of life and for it to at least try and turn the engine?

Sidicks

[HAB]

sidicks said:

HAB said:

If it was so drained that it wouldn't even turn the starter over, you'll probably need to remove it and charge it overnight.

Edited by HAB on Sunday 11th January 17:44

Surely after driving it for 1.5 hours and letting it idle for another 1 hour+, I should expect at least a spark of life and for it to at least try and turn the engine?

Sidicks

Actually, yes I would have thought that after that amount of driving, you'd have enough juice to turn the engine over. It's probably your battery - I returned a Bosch Silver to Costco recently that wouldn't hold a charge for mor than about a week of no use. The replacement I got proved the original was faulty.

[sidicks]

HAB said:

Actually, yes I would have thought that after that amount of driving, you'd have enough juice to turn the engine over. It's probably your battery - I returned a Bosch Silver to Costco recently that wouldn't hold a charge for mor than about a week of no use. The replacement I got proved the original was faulty.

I think a new Porsche battery is £280 , and I assume this is a consumable item and hence not covered by warranty.

Is 2 years, 10 months (and 15,000 miles) acceptable for a battery in a Porsche?

Sidicks

[POORCARDEALER]

Sounds to me like the battery is goosed........If your alternator had gone you would have a warning light on the dash.

If it isnt covered under warranty dont buy one from Porsche at that price...find a Bosche one, it should be £120 ish with a three year warranty.

[HAB]

sidicks said:

HAB said:

Actually, yes I would have thought that after that amount of driving, you'd have enough juice to turn the engine over. It's probably your battery - I returned a Bosch Silver to Costco recently that wouldn't hold a charge for mor than about a week of no use. The replacement I got proved the original was faulty.

I think a new Porsche battery is £280 , and I assume this is a consumable item and hence not covered by warranty.

Is 2 years, 10 months (and 15,000 miles) acceptable for a battery in a Porsche?

Sidicks

Batteries do need replaced, as their ability to hold a charge diminishes over time. Getting on for 3 years is not bad, but it's not great either.

Forget buying one from Porsche, that is a ridiculous price, I've found The Bosch Silver I mentioned earlier is a decent buy. You should be able to pick one up with the correct amp rating for the 997 for about £70.


eta - maybe more like £100 for the 997.

Edited by HAB on Sunday 11th January 18:09

[bcnrml]

sidicks said:

HAB said:

Actually, yes I would have thought that after that amount of driving, you'd have enough juice to turn the engine over. It's probably your battery - I returned a Bosch Silver to Costco recently that wouldn't hold a charge for mor than about a week of no use. The replacement I got proved the original was faulty.

I think a new Porsche battery is £280 , and I assume this is a consumable item and hence not covered by warranty.

Is 2 years, 10 months (and 15,000 miles) acceptable for a battery in a Porsche?

Sidicks

To your final question, the answer depends on how flat the battery was before your attempt to revive it and whether it has previously been flat or close to flat in very cold conditions (as happened over the preceding fortnight).

From the mileage you report, I suspect the battery is dead and that it will not hold its charge any longer. It could be the alternator, of course, but I'd start by changing the battery.

Good luck (and hullo!)

[sidicks]

Brief update:

Folowing advice from a member on Porsche Club GB forum, I called Porsche Assist and requested a 'Prestige Van' with a new battery, which was fitted this morning. Total cost £150 and no potential issues with existing warranty (or new OPC warranty at renewal time, if I choose to go down that route).

Much better than paying the OPC £280!

Sidicks