LehmanZ06

I have a set of Hoosiers on my car.

My 2010 GT3 is sitting on my trailer at my warehouse. I don't want to put the street tires on and drive the car home.

I have a autocross next weekend that I might attend.

I don't use a trickle charger.

Can I charge the battery by just letting the car run at idle in neutral for like 20 minutes ?

Is this bad ?

Will it work ? Or do I need to drive it for 10-20 miles and put a load on the car ?

Thanks,
Lehman

PS...I would have asked Rad when I saw him 2 days ago but I didn't realize I would be lazy and not want to swap wheels back and forth.

911SLOW

Yes, it will charge. The alternator's output is almost linear in all RPM when you have no loads.

LehmanZ06

By no loads, do you mean no radio or a/c running OR do you mean with the engine idling ?

drl

I am confused - why do u need to charge battery?

LehmanZ06

Car is currently sitting on trailer with Hoosier on.

I think I can get another autocross out of the tires that I have on the car. I have multiple sets of tires and wheels. Some sticker sets, which I don't want to use for a local event, and am saving my stickers for national autocross competition.

Since the event is next week, and the car is already on the trailer.....I don't want to take the time and energy to change to street tires.....drive the car, and then before the competition put the Hoosiers back on and then put the car back on the trailer.

And since I don't use a trickle charger...I was thinking I could just run the car while on my trailer for like 20 minutes (I will unhook the rear straps as I don't want them to get to hot from the muffler etc.

drl

I am missing something. Still don't know why u need to charge battery. And u can drive hoos on street for a few minutes, no biggie.

tlarocque

Or just "invest" in a trickle charger and an extension cord?

drl

Ok someone tell me why the battery needs to be charged after sitting for - what? - a week or two. Get in car, start car, drive car. Done. No?

Ur20v

It will charge but you need to raise the rpm over 1500rpm just briefly to load the regulator otherwise there's a chance it will sit not charging.

Its certainly not the best way.

Cheers
Jay

LehmanZ06

Ok, guess then I will drive it around.

Get it off the trailer.....drive it around on A6's.....stick it back on the trailer.

How long to charge ?

TRAKCAR

In 2 weeks, IF it does not start you can just push start it no?

Maybe even while rolling it out of the trailer?

RAPID

If the car will starts, no need to charge the battery...Unless you expect the battery to discharge completely before your next engine start?
To charge the battery fully you need 20-30 minutes.

wanna911

Because it seems this car isn't driven regularly, and Porsche's sitting = drained battery. There is nothing worse than being at the track/autocross and having a low charge battery that won't start, you have to keep jumping it over and over again.

I would advise to just buy a trickle charger, it's probably a lot easier than taking the car off trailers, driving around, and putting car back on trailer.

drl

Since he said the event is next wknd i didnt think that extra week btwn now and then would be such a big deal. All this fuss - just get a trickle charger!

LehmanZ06

Bought the Porsche trickle charger.

Thanks !