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Battery Voltage during driving


Andrewkb
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I've just installed a voltmeter and it shows 13.x to 14 during driving.

However, I notice that when picking up from stop at traffic light, sometimes it'll drop to 12V holding consistently until I reach cruising speed... why is this so ?

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you mean when the car is staionary in traffic and meter shows it is at 12v? this is normal.

 

or

 

you mean the voltage stays at 12v all the way until you reach cruising speed, not up to 13+-14v when you start driving off? this is abnormal.

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Neutral Newbie

when you car is idling, the alternator is not charging the battery, which is why it holds at the 12v region.

 

conversely when you start accelerating, the alternator will use some of the energy produced by the engine to charge the battery, thereby resulting the increase in voltage.

 

hopefully i got it right, anyone can correct me if i'm wrong? [sweatdrop]

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Neutral Newbie

mine is ard 13v either idle or driving. when air-con/fan kicks-in, the volt will drop to abt 11-12v. when the turn indicator is on, voltage up/down 11-13v. havent really notice during pickup. will monitor.

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basically on idle, the alternator are charging the batteries at around 13+ to 14 volt nod.gif The alternator is providing most of the electricity instead of the battery, the car will depends entirely on the battery during engine crank start sly.gif

 

So, when you are doing a pickup from traffic light stops, all the electrical systems (Fuel injectors, Fuel Pump, Air-Con etc...) for your car are draining lots of current so that's why there's a slight drop to 12V sly.gif after the pickup stage, while crusing, the load on the engine is not as demanding as the initial pickup (remember during pickup, your engine speed (RPM) will goes up & it returns back to around 3K RPM during crusing) wink.gif

 

you can read more here :

 

 

 

http://www.autosite.com/garage/subsys/bachargs.asp

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nope, once your engine is crank start, the alternator will start charging liao sly.gif & should maintain during normal idling or driving at around 13+ to 14v. Under hard accelaration, the demand on the the electrical current is more so the voltage will drop down slightly 12v and stays around there wink.gif

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Neutral Newbie

hmmm...

 

but for my ride it seems to be at ard 12V during normal idling, e.g. stopping at traffic lights. [dizzy]

 

once i move off it'll go back to e 13-14.2 range. [sweatdrop]

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For my case, most of the time 13.8 to 14.1

However, on a "few" occasion it goes down the 12.1 during pickup. Other time, it sticks to 13+V to 14V even during pickup.

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Neutral Newbie

Mine is maintaining around 13.8 to 14.2 when idle and on the move. Only when I switch on my 3 fog lights, hi beam, cd and blasting, walkie talkie, hazards, all 4 interior room lights, then my voltage drops to 12.7. At stop without idling, it's at 12.5.

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I've just installed a voltmeter and it shows 13.x to 14 during driving.

However, I notice that when picking up from stop at traffic light, sometimes it'll drop to 12V holding consistently until I reach cruising speed... why is this so ?

 

Too many gadgets? [rolleyes][laugh][laugh][laugh] What's the amperage of your batt?

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65Ah or 70Ah is already powerful enough lah......... I think you are worring about nothing. Why don't you ditch all your measuring instruments and enjoy some stress-free driving instead? [sly][laugh][laugh][laugh]

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Neutral Newbie

Hehehehe.. you are a classic case of putting too many monitoring gadgets and start getting panicky when thinks are not precise to your expectation..

Edited by Cool
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