is it safe to intall a new battery while the car is running?
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Old March 27th, 2008, 10:35 AM   #1
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is it safe to intall a new battery while the car is running?


i have a optima battery that got drained just before i got my new alternator, id like to put it back, can i start the car, pull the current battery and intall the optima so that the alternator charges it?
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Old March 27th, 2008, 11:00 AM   #2
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sounds like a really dumb idea. Go get a $15 battery charger at Wal-Mart. If you can't afford that in order to be safe, then sell your car and buy a honda.
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Old March 27th, 2008, 11:01 AM   #3
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the day i ever will even consider buying an import will be the day i have a kid

sigh ill just take it down to autozone and get it charged
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Old March 27th, 2008, 11:13 AM   #4
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do not pull your battery you will fry solid state components in your car
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Old March 27th, 2008, 11:29 AM   #5
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thnx, thats y i asked before i did it
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Old March 27th, 2008, 11:39 AM   #6
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Don't try to charge a dead battery with an alternator, puts alot of stress on it (the alternator). Alts aren't meant to to charge, only maintain.
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Old March 27th, 2008, 11:49 AM   #7
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it doesnt put any stress on the alt. it will put out the same volts and amps if it was charged already its just bad for the battery
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Old March 27th, 2008, 11:53 AM   #8
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Stupid idea to use you alternator to charge a totally discharged battery. Do that with a GM product and you will buy a new alternator. Charge the battery first.
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Old March 27th, 2008, 12:13 PM   #9
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I don't even think that's possible. Won't the car turn off.
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Old March 27th, 2008, 12:25 PM   #10
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your cars will turn off mine wont because i dont have any computers in mine other than an ignition module thats not very high tech at all
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Old March 27th, 2008, 01:09 PM   #11
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Car won't turn off even on a computer controlled car because the alternator will still put out volts/amps - however the battery regulates the voltage to 12.5ish and without it you'll likely get voltage spikes etc. that may cause electrical damage. And yes, again, trying to charge a dead battery with an alternator can certainly damage it, most likely you'll be ok but the battery may not fully charge.
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Old March 27th, 2008, 01:11 PM   #12
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charging a battery is free in most places..
just put the thing in your trunk and drive it to a local store..


problem solved.
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Old March 27th, 2008, 01:16 PM   #13
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I would think the biggest problem with pulling the battery while the car is running is that you no longer have a common ground other than the car chassis which can't soak up much current. The battery is like a big electronic buffer.
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Old March 27th, 2008, 02:17 PM   #14
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Originally Posted by mdvaldosta View Post
Car won't turn off even on a computer controlled car because the alternator will still put out volts/amps - however the battery regulates the voltage to 12.5ish and without it you'll likely get voltage spikes etc. that may cause electrical damage. And yes, again, trying to charge a dead battery with an alternator can certainly damage it, most likely you'll be ok but the battery may not fully charge.
the battery does not regulate anything the voltage regulater does that hence the name "voltage regulator" what the battery does is absorbs fly back voltage from actualtors turning on and off which can go all the way up to 25 volts and will fry solid state components. so with out the battery the fly back voltage will kill things like your ecu tfi module ect. and your car will die
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Old March 27th, 2008, 04:55 PM   #15
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why dont u just put your battery in and jump your car with another?????
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Old March 27th, 2008, 04:56 PM   #16
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Originally Posted by ryans88gt View Post
sounds like a really dumb idea. Go get a $15 battery charger at Wal-Mart. If you can't afford that in order to be safe, then sell your car and buy a honda.
+1 on this one i bought a 2-6 amp slow charger and i love it... it was like 12 dollars at wally world
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Old March 27th, 2008, 05:27 PM   #17
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Niceeeee
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Old March 28th, 2008, 12:02 AM   #18
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Originally Posted by HACKGT350 View Post
the battery does not regulate anything the voltage regulater does that hence the name "voltage regulator" what the battery does is absorbs fly back voltage from actualtors turning on and off which can go all the way up to 25 volts and will fry solid state components. so with out the battery the fly back voltage will kill things like your ecu tfi module ect. and your car will die
You totally contradict yourself in this statement. Yes, thats what the voltage regulator is there for, but the battery isn't the voltage regulator... the voltage regulator is. If the alternator sent out 25v that would fry stuff with or without a battery. Removing a battery with the car running will technically do nothing to the cars electronics and the car will stay running, unless connection for the power from the alternator to the rest of the car is actually made at the battery and that connection seperates when you remove the battery. The only thing is you run the risk of is the pos. lead touching ground and burning the alternator up... which is a pretty big risk, one that I wouldn't take.

Also, like mdvalosta said before, alternators aren't meant for charging batteries, only maintaing them. You wont get much of a charge for of a dead battery with an alternator.
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Old March 28th, 2008, 12:49 AM   #19
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i never said the alt was putting out something like 25v it could be any other component in the car. and yes i know the battery isnt a voltage regulator its more like sponge to absorb fly back voltage like i said from any other compnent in the car. i said only the voltage regulator regulates voltage. and yes i know the battery isnt the only thing that takes in fly back voltage
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Old March 28th, 2008, 01:16 AM   #20
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The only things that "puts out" voltage in the car is the battery and the alternator. I've been in the 12v field for many years now and have never heard of this "fly back voltage" that you're talking about, capacitence maybe. The only thing that a battery absorbs is a voltage drop, i.e. such as when you turn on the rear defrost, which is a large draw on the charging system. Without the battery present to supply the extra current needed for the initial spike in current(not voltage) when you first turn it on, the alternator would eventually fail prematurely due to excess load.
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