Will the battery charge sitting at idle?

[sy0296]

Just curious because some cars will not spin the alternator fast enough to charge the battery.

I left the car sitting to too long and the battery drained. I just jump started the car but it's a bit late to go drive around a bit. Will our car still charge the battery at idle or do I need to drive around the block a few times?

[S4 00 2.7]

No, wont be enough. You need to hook it up to a charger overnight (slow trickle charger).

[zillarob]

Um, if the guage reads more than 12.5, I think it is charging.

[sy0296]

No, wont be enough. You need to hook it up to a charger overnight (slow trickle charger).

TY! I leave the charger hooked up for at bit. Thanks!

[MDJ]

14.4v is the charging voltage for any alternator on a modern car. I obviously you can check this with a volt meter across the battery with the engine at idle.
A functional alternator should charge a battery at idle.

[DiscoPotato]

Yes it will charge.

[BITRBO]

^IDK about that. When I worked at PepBoys way back when, they had a pretty badass battery/alternator tester would tell you to hold the RPM's above 2,200 (and then 3k) while it read/tested the system... Seems pointless if it charges at idle just the same.

[airjawed]

Charging and charging well at idle are 2 different things. With heat, lights and radio on the ability to charge reduces a bit. With those off and with engine running higher rpm it will charge better. The point at which it does a good job or not depends on the alternator and pulley/rpm.

Overnight trickle charge is the proper way.

[somebody5788]

^IDK about that. When I worked at PepBoys way back when, they had a pretty badass battery/alternator tester would tell you to hold the RPM's above 2,200 (and then 3k) while it read/tested the system... Seems pointless if it charges at idle just the same.

It ALSO tests at idle conditions.......... You have to test both in order to actually do a thorough test on the alternator

Assuming you don't turn every single electronic load on that you can the battery will easily charge at idle.

Alternators these days are electronically controlled to provide the same amps from idle to full RPM.

Trickle charging would be better but in a pinch it's not necessary.

[BITRBO]

It ALSO tests at idle conditions.......... You have to test both in order to actually do a thorough test on the alternator

Assuming you don't turn every single electronic load on that you can the battery will easily charge at idle.

Alternators these days are electronically controlled to provide the same amps from idle to full RPM.

Trickle charging would be better but in a pinch it's not necessary.

You might be right... It's been about 13yrs since I worked there. Then again, our cars are 14yr-old technology, so when you say "cars these days" does it still apply?

Agreed on the hooking up a wall charger - You can't duplicate charge quality and speed from an a/c source.

[somebody5788]

You might be right... It's been about 13yrs since I worked there. Then again, our cars are 14yr-old technology, so when you say "cars these days" does it still apply?

Agreed on the hooking up a wall charger - You can't duplicate charge quality and speed from an a/c source.

Ya even my 1994 Jeep is supposed to be this way, though it's OLD tech and not quite up to standards.