Re-Charging a Car Battery by Driving

[Texas Star]

If someone leaves the key in position to hear the radio in a sitting car and plays some tapes, and the key remains in this auxilliary position for about two hours, does that harm anything? I forgot to turn the switch off after I took out a tape.

The car started okay and I drove 3.7 miles home with the A/C off to avoid draining the battery. As far as I can tell, everything is okay, except that the headlights might not be quite as brilliant as usual when on "Bright", which I tested.

How long does it take to charge a battery by driving under such conditions?

How about if the battery has had to be "jumped", which happened to a co-worker last week?

I've heard times everywhere from ten minutes to an hour. What do you guys think?

Thanks,

T-Star

 

[Marshwheeling]

If the battery is in good condition, it won't run it down much to play the radio for a couple of hours. Leave the lights on for six or eight hours, and you will need a jump.

Jump a car that has sat all day with its lights on, and it will restart on a good battery in just a few minutes. I have no idea how long it takes to fully recharge.

I have started using a Fluke meter to monitor the condition of my batteries. A fully-charged battery in good condition should read 12.6-12.8 v after standing overnight. Cranking the starter should not drop the voltage below 10 v. Any less, and the battery is on its way out.

 

[CelticSire]

I'm not a mechanic, nor did I sleep in a Holiday Inn last night. The answer is: it depends. There are many variables that can affect charging rates: age of battery, how well the alternator is functioning, voltage regulator, ambient temperature ( 110 here for us in Dallas today YAY), etc. If it started and you were able to drive it home, and it starts again after sitting, you should be okay. (Most people don't realize that excessive heat is just as bad as excessive cold on a battery.)

 

[setxn]

Charging weak battery with the alternator is a good way to end up replacing both-especially a car that is old enough to have a tape player.

 

[sar4937]

All of the above, but I haven't had an accessory position since my 2000 Silverado. Most newer vehicle's alternators will overheat bringing a depleted battery up, especially in summer. T-Star, that wasn't an 8 track tape, was it?

 

[snowman]

If it started and you were able to drive it home, and it starts again after sitting, you should be okay.

Sound words here. The only slight revision I might make would be, "If it cranked at normal speed when you started it and you were able..."

Andy

 

[setxn]

Better yet a 4 track tape player-just might be giving away my ancient history with that! Seriously- I'd get the battery charged then have the system checked out. Could save some money and misery down the road, might get lucky and be a dirty connection or something else that's cheap and easy. This never happens to me but I've heard it is possible.

 

[Stevens]

How old is the battery? I find usually they last about 3 years maybe 4 if I have a problem with them after that I replace them.
Steve W

 

[Rule3]

How old is the battery? I find usually they last about 3 years maybe 4 if I have a problem with them after that I replace them.
Steve W

You are lucky to get three years. I don't care what brand. As was mentioned, constant brutal heat just kills batteries.

 

[rags]

First of all I'm really surprised you don't already know! I don't think that 2 hrs on aux will hurt the battery. The alternator will recharge the battery as needed. Anyway, What's a tape?

rags

 

[keith44spl]

Who really knows...I once left a 8 track playin 'The Best of Steppenwolf' on the tape deck all nite long
in an ol '63 Chevy Impala SS with a four & a quarter horse 409, four on the floor and a long legged blonde...


Su Amigo,
Dave

 

[ditrina]

Who really knows...I once left a 8 track playin 'The Best of Steppenwolf' on the tape deck all nite long
in an ol '63 Chevy Impala SS with a four & a quarter horse 409, four on the floor and a long legged blonde....


Su Amigo,
Dave

I Like it!!............................Noooo I REALLY LIKE THAT!!!!!!!

Only I was in Memphis..

 

[Texas Star]

The car started normally, and the tape was an 8-track, I think. Belinda Carlisle...

The battery is probably about three years old, and I'm planning to get it checked or replaced soon.

I heard that about heat depleting batteries, and it has me concerned. As Celtic Sire noted, it was 110 degrees here today, and even at night, it may be 100 degrees until midnight. And winter is coming, and it'll probably be a cold one again. Yep, battery will probably get replaced.

Thanks for the help.

 

[venomballistics]

charge while driving is probably ideal. If it werent a good system we'd all be hand grenading our batteries every month.
about the only issue here is that car batteries dont like being deep cycled. Meaning being drained hard and recharged as could be the case with a mutant stereo.

 

[bobelk99]

Occasionally I leave key on or whatever (Alzheimers according to spouse) and have to jump vehicle due to low battery.

I just let it run for 15 minutes and turn it off, and forget the whole thing. Have worked fine more than once.

I realize that is a redneck solution, not considering the 48 variables that may exist.

Good part is it works.

I keep a Clore JNC660 in the toolbox, so jumps are no problem.

 

[37pack]

Be sure to check the terminals for corrosion. That alone will stop current flow. Remove the terminal ends and clean them. If you have acid corrosion on the top of the Battery. Pour coke on it and flush well with water. Like stated above if the battery is old buy a new one.

 

[Iggy]

I'm kinda like Dave Keith.. Back about 63, I spent a lot of Sat nights out by the cemetery with a good lookin' filly a listenin' to the radio and watchin' the grass grow.

Never had a problem rechargin' the???... Whut was we talkin' about?? ...... oh yeh... the battery!!!

 

[redlevel]

You old boys is just braggin', and lyin' 'bout your age, too. More like 1953 instead of 63, weren't it?

 

[Bekeart]

ALTERNATOR IS A BATTERY CHARGER !!!

Your alternator is a regulated VOLTAGE source with a rated output of up to X Amps.
Meaning that it will put out UP to X Amps into a load while supping regulated voltage.

Alternators have both voltage regulation and current limiting to protect batteries and accessories.

The alternator does not know if its output is being used to power accessories or charge the battery.
The alternator tries to maintain a constant system voltage, by delivering current up to its amperage limit.
Amps is Amps. Volts is Volts.

Your battery is charged by the alternator every time you drive. Otherwise you would have to hook up a battery charger frequently.



Bekeart

Charging weak battery with the alternator is a good way to end up replacing both-especially a car that is old enough to have a tape player

.

Sir, the car alternator is should never to be used as a battery charger, unless of course you work at NAPA.

 

[Iggy]

You old boys is just braggin', and lyin' 'bout your age, too. More like 1953 instead of 63, weren't it?

Naw, but it was a 53 Chevy...