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does the battery charge from alt at idle? or driving?

Posted: Thu Jun 10, 2010 4:19 pm
by cgneon
so, replaced my battery some months ago due to lack of voltage, and cranking amps... symptoms started as a slower start with crazy guages goin thorugh the test cycle.. then just wouldnt start

my drive to work is literally across the street, so, start up, drive 15-20 seconds shut off, and repeat in the afternoon.. and i dont do alot of driving on the weekends....

i am sure this is not good since the constant starting, and no time to charge is slowly taking its toll on the batteries ability to start the car,...

scanguage last read 12.2 when i just shut the car off this afternoon, was 13.5or so while driving across the street.. im wondering if the alternator charges while the car is idling, if so i can let it idle once in awhile for 30min or so during the week when i get home from work to compensate...

although i thought i read somewhere that the alt only charges once you get past idle, and have the car running up into 3krpm range... cant remember the source..

any help is appreciated..


edit: after some googling, it seems a: the short trips can kill a battery (which i knew) b: some vehicles charge at idle, some dont..... so i can try and let he car idle at work or home on some days, but now i think im considering this, i stumbled on in some other forums

http://www.amazon.com/Wagan-2017-Solar- ... B000VHT9GS


actually this one has better reviews..
http://www.amazon.com/Vehicle-Battery-1 ... sbs_auto_2

might solve my problems..

Posted: Thu Jun 10, 2010 5:05 pm
by occasional demons
It should charge at idle, as long as there is nothing using amperage while it is idling. Leave the radio, lights, blower motor, etc. off. It should gradually be any where between 13.5 and 14.5 volts once it levels off.

That solar charger might work if you let it sit for a week, but i doubt 125mA is going to recover the amperage used to crank the engine. A plug in battery maintainer might do a better job. 1/8 amp is going to do nothing. It prolly wouldn't charge your cell phone in 8 hours.
Also, IDK if our power outlets are switched on with the key off or not.

Drive to the store, and buy a soda, or something after work twice a week; it will do far better, not only for the battey, but everything else in the car that needs to be brought up to operating temps.

Posted: Thu Jun 10, 2010 5:22 pm
by eastwoodsn352
how about just walking to work?

Posted: Thu Jun 10, 2010 5:52 pm
by cgneon
eastwoodsn352 wrote:how about just walking to work?
thats not the american way... j/k srsly, south florida weather can rage thunderstorm in the afternoon with no notice... i may just start taking the bicycle to work and deal with it if it rains..
occasional demons wrote:It should charge at idle, as long as there is nothing using amperage while it is idling. Leave the radio, lights, blower motor, etc. off. It should gradually be any where between 13.5 and 14.5 volts once it levels off.

That solar charger might work if you let it sit for a week, but i doubt 125mA is going to recover the amperage used to crank the engine. A plug in battery maintainer might do a better job. 1/8 amp is going to do nothing. It prolly wouldn't charge your cell phone in 8 hours.
Also, IDK if our power outlets are switched on with the key off or not.

Drive to the store, and buy a soda, or something after work twice a week; it will do far better, not only for the battey, but everything else in the car that needs to be brought up to operating temps.
ya the solar reviews i see are its not gonna do much at all, if it even did maintain, it would never be strong enough to recharge it..

dont drink soda, but ill take it for spin on the highway a couple times a week (or on the weekend, if i start taking the bike) and see how that does..

thx guys

Posted: Thu Jun 10, 2010 6:13 pm
by heydockyle
occasional demons wrote: Also, IDK if our power outlets are switched on with the key off or not.
Our Cig Lighters are only on with the key.

Posted: Thu Jun 10, 2010 6:16 pm
by cgneon
heydockyle wrote:
occasional demons wrote: Also, IDK if our power outlets are switched on with the key off or not.
Our Cig Lighters are only on with the key.
i would hardwire it of course, but it has been rendered junk anyway..

Posted: Thu Jun 10, 2010 6:27 pm
by heydockyle
I've never heard of a car that doesn't charge at idle.

Why not just get a battery tender? We have like 4 of them in my garage, 2 for the quads and 2 for the cars.


http://www.amazon.com/Battery-Tender-02 ... 789&sr=8-1

or this

http://www.amazon.com/Battery-Tender-02 ... 789&sr=8-2

Posted: Thu Jun 10, 2010 7:55 pm
by cgneon
heydockyle wrote:I've never heard of a car that doesn't charge at idle.

Why not just get a battery tender? We have like 4 of them in my garage, 2 for the quads and 2 for the cars.

2nd floor apt, no garage, just a parking spot out front.. fail, but good idea tho..

Posted: Thu Jun 10, 2010 8:11 pm
by occasional demons
I have had two examples of vehicles that wouldn't charge at idle. Both Mitsubishis. Prolly not a normal feature tho. Neither would charge until the rpms were raised when started. Once charging, they would keep charging.

Posted: Thu Jun 10, 2010 8:23 pm
by fixitmattman
The neon charges at idle, rule of thumb is you should read about 2v over base battery voltage. If your drive is as short as you say, you may not see that as the battery could be putting a hell of a load on the alt.

You really just need to drive it more. You're using more a bunch of battery power to start, and not driving enough to restore a full charge. At some point you just run out of juice, probably nothing wrong with the car other than not being driven enough.

Re: does the battery charge from alt at idle? or driving?

Posted: Fri Jun 11, 2010 12:47 pm
by iskyfly
cgneon wrote:
scanguage last read 12.2 when i just shut the car off this afternoon, was 13.5or so while driving across the street.. im wondering if the alternator charges while the car is idling, if so i can let it idle once in awhile for 30min or so during the week when i get home from work to compensate....
isn't idling for extended amounts of time illegal?
plus, wouldnt that just be a waste of gas?

maybe a battery tender would be better?

Posted: Fri Jun 11, 2010 1:00 pm
by heydockyle
cgneon wrote:
heydockyle wrote:I've never heard of a car that doesn't charge at idle.

Why not just get a battery tender? We have like 4 of them in my garage, 2 for the quads and 2 for the cars.

2nd floor apt, no garage, just a parking spot out front.. fail, but good idea tho..
Extension cord out the window :)

Posted: Fri Jun 11, 2010 1:38 pm
by darthroush
heydockyle wrote:
cgneon wrote:
heydockyle wrote:I've never heard of a car that doesn't charge at idle.

Why not just get a battery tender? We have like 4 of them in my garage, 2 for the quads and 2 for the cars.

2nd floor apt, no garage, just a parking spot out front.. fail, but good idea tho..
Extension cord out the window :)
That's kind of what I did. I'm in a small apartment building, and we have outside receptacles. I just plugged an extension cord it, and put the battery tender in the engine bay so I could completely close the hood. I also ran the extension cord under the front bumper and up by the radiator so it wasn't sitting on the paint.

Posted: Fri Jun 11, 2010 2:14 pm
by OB
All cars that use an alternator charge at idle, unless there is a problem. Older cars that used a DC generator might be different.

The PCM doesn't care what RPM you're at, it simply looks at battery voltage and adjusts the regulator accordingly at that given time. Of course, the alternator naturally produces more output at higher revs, but there is no minimum engine speed required to recharge the battery. Anytime the vehicle is running, voltage should be 13.5-14.3 or so, give or take. If it drops under 13 for more than a couple seconds, you may have an issue. 12.65V is what a fully charged battery should be at when not receiving a charge. So long as you make sure you get close to this number, you can feel safe about shutting the engine down. 12.5 should be enough.

Posted: Fri Jun 11, 2010 4:40 pm
by cgneon
ya 13.7-9 at idle, 14 ish while driving.. so far about 12 when i turn the car off..

im goin to just order the battery tender junior from amazon for 27$ that was linke above, and plug it in at work on saturday when noone is there.....

Posted: Fri Jun 11, 2010 4:48 pm
by heydockyle
How long you at work on Saturday?

The bigger one is better for charging, the junior is moire of a maintainer.

Posted: Fri Jun 11, 2010 4:50 pm
by cgneon
heydockyle wrote:How long you at work on Saturday?

The bigger one is better for charging, the junior is moire of a maintainer.
8hrs

Posted: Fri Jun 11, 2010 5:05 pm
by heydockyle
Ehh. It should be fine then.

Posted: Fri Jun 11, 2010 5:13 pm
by darthroush
Another thought, with all of that really short driving, do you change your oil often? That's killer on engine oil as well...

Posted: Fri Jun 11, 2010 5:28 pm
by cgneon
every 3k, and oil always looks new

Posted: Fri Jun 11, 2010 5:59 pm
by racer12306
It may look new but you can't see it's actual condition. I'd be curious about fuel and water dillution.

Posted: Fri Jun 11, 2010 9:12 pm
by ZeroChad
I'm sorry man, but driving your car in repeated 15-20sec shutoffs is not good for your battery charging cyles. That's a 1min walk...

IMO I would save it for the weekend adventures.

Posted: Sat Jun 12, 2010 12:05 am
by OB
Indeed, running an engine for less than 4-5 mins is much harder on almost every mechanical part in it. It's a good idea to get it up to full temp on every trip. Not only with your internal parts wear faster, but your starter and electrical system in general is going to take a beating.

Posted: Sat Jun 12, 2010 5:25 am
by darthroush
racer12306 wrote:It may look new but you can't see it's actual condition. I'd be curious about fuel and water dillution.
:withstupid: With 30 second drives multiple times a day (that's like a 3 minute walk?), those have got to be UP there.

Posted: Sat Jun 12, 2010 9:12 pm
by Marcel
Starting your car for a 20 seconds drive? :tardbang:
really.... a lot comes into my mind but they all come down to basically one answer:
stop.
doing.
that,
start.
walking.

come on, weather? oh big boo hoo, if it's 20 seconds drive it's barely 2 min. walk! :banghead:

please, don't tell me you go to the gym because you want to excercise more :rofl:

Posted: Sat Jun 12, 2010 9:37 pm
by cgneon
lol, k its a bit more than 20sec, i may haev exaggerated.. but when its 100degrees and you work outside everyday, the last thing you want to do is walk in .... more heat....


but im gonna just take the bike from now on, unless its storming.. so i can keep the wear off the car..

Posted: Sun Jun 13, 2010 3:42 am
by Marcel
well if you work outside all day, those 5 min. walking towards and from work don't really matter anymore, right? :rofl: :P
but yeah, good idea, the engine suffers the most from running cold (cold for engine measures obviously ;) ) so you're doing the right thing for your car now :)

Posted: Wed Jun 16, 2010 4:29 pm
by Skyjay
If you REALLY NEED IT, out of insanity, i offer this option:
Buy one of those portable emergency-start dealies that have an internal battery you can charge at work, and keep your car battery unplugged.
The consistent charging/discharging of the battery is going to severely shorten it's life, so why not kill a 30/40 item instead of a 80/90 item.
Downsides would be your radio stations wouldden't stay, and if you don't insulate the battery cables, they could short.

Once the car is going, the generator provides enough electrical power to run everything. I don't see any OBD problems off the top of my head. I practically ran without a battery for about 3 months, pain to jump it each time (you can find one that will start from a cigarette lighter), but it can save you in the long run.

Posted: Wed Jun 16, 2010 4:38 pm
by occasional demons
Skyjay wrote: I practically ran without a battery for about 3 months, pain to jump it each time (you can find one that will start from a cigarette lighter), but it can save you in the long run.
You may charge the battery from the power outlet, but there is no way you will get enough amps through that circuit to crank the engine.

Wal Mart batteries are about $40ish, so why go through the hassle?

Posted: Wed Jun 16, 2010 5:20 pm
by Skyjay
occasional demons wrote: Wal Mart batteries are about $40ish, so why go through the hassle?
If only we all hard access to a wal-mart in ohio, they start at $70 here.