Alternator vs. Battery
#1
Alternator vs. Battery
So, how to you tell which is going bad? I read to start the car; pull off the negative cable and if the car stalls/dies it is an alternator issue.
My battery is an odyssey PC925 which is about 2 1/2 years old and lives on a battery tender when not in use. A new battery is only $170 and really easy to install.
Sometimes when I try to start I get a single click and nothing. I have clutch in and have gas pressed as I turn the key and that seems to help. Interior lights work fine when I open the door.
If it is the alternator can I just purchase one at Auto Zone for less than $200, would this work? I put in 2004 911 and got a list fits your vehicle.
Any thoughts?
My battery is an odyssey PC925 which is about 2 1/2 years old and lives on a battery tender when not in use. A new battery is only $170 and really easy to install.
Sometimes when I try to start I get a single click and nothing. I have clutch in and have gas pressed as I turn the key and that seems to help. Interior lights work fine when I open the door.
If it is the alternator can I just purchase one at Auto Zone for less than $200, would this work? I put in 2004 911 and got a list fits your vehicle.
Any thoughts?
#6
^^ what he says ^^
NEVER disconnect our battery when the engine is running....
What does the voltmeter (in the dash) read? Should indicate between 13.5 - 14.5v max.
A fully charged battery = 12.6v @ the terminals but that's no guarantee it's OK, it needs to be load tested to confirm it will start your engine.
NEVER disconnect our battery when the engine is running....
What does the voltmeter (in the dash) read? Should indicate between 13.5 - 14.5v max.
A fully charged battery = 12.6v @ the terminals but that's no guarantee it's OK, it needs to be load tested to confirm it will start your engine.
#7
take the battery to an auto parts store and have it load tested. this will tell you if theres a bad plate r the battery is defective. and stop pressing the gas pedal for startup. its a fuel injected car and completely uneeded. you can also take the alternator to the same parts store and have it tested as well
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#8
Ok. Glad I asked. I did not like the idea of disconnecting the battery when the car was running. The part for a new alternator is so inexpensive. Everything is leading towards the alternator. If possible I will try to have the battery tested.
#9
Basic battery/alternator testing
Check the battery voltage with the ignition off
Check the battery voltage with the car running
#11
I replaced the voltage regulator on my 997. It's a pretty simple job, and cheap. You might do that vs a new alternator, as you have to take the alternator out in either case. Maybe you can recycle this for a GT3. (I haven't tried and others say it's different)
-td
https://rennlist.com/forums/996-gt2-...n-brushes.html
https://rennlist.com/forums/997-foru...error-diy.html
-td
https://rennlist.com/forums/996-gt2-...n-brushes.html
https://rennlist.com/forums/997-foru...error-diy.html
#12
Reviving an old thread with the search feature. I just had the battery light come on in the dash for the first time ever. The battery is one year old. Its currently at the auto parts store being tested. Typically what is the issue when that light comes on?
#13
Low voltage - the alternator is not supplying enough power (v) when the engine is running: output = greater than input.
A simple (though not infallible) way to test the charging system is to put a voltmeter (DCv) across the battery terminals (everything off) after the car has sat for a couple of hours - voltage should be 12.6v for a fully charged battery.
Then check the voltage as above with the engine running, everything switched off (fans / lights etc) voltage should read approximately 13.5 - 14.5v.
This is really a rough check as both the battery and alternator should really be load tested to be sure...….
As a reference, battery terminal voltages are:
12.6v = fully charged.
12.4v = 75% charged.
12.2v = 50% charged.
12.0v = 25% charged.
A simple (though not infallible) way to test the charging system is to put a voltmeter (DCv) across the battery terminals (everything off) after the car has sat for a couple of hours - voltage should be 12.6v for a fully charged battery.
Then check the voltage as above with the engine running, everything switched off (fans / lights etc) voltage should read approximately 13.5 - 14.5v.
This is really a rough check as both the battery and alternator should really be load tested to be sure...….
As a reference, battery terminal voltages are:
12.6v = fully charged.
12.4v = 75% charged.
12.2v = 50% charged.
12.0v = 25% charged.
#14
Appreciate the advice. The auto parts store charged and tested the battery and said it was good. I put it back in the car and and started it. The battery light came on immediately. I put the voltmeter on the battery and it was only charging at 12.2v. I'm guessing its the alternator.
In regards to the alternator, does the Porsche one have magic dust in it? Its freaking $1,200 where the 150amp reman Bosch is $269.
#32 - https://www.porscheatlantaperimeterp...rimLevel=18177
https://www.rmeuropean.com/Products/...6-efaf80cb153d
Unfortunately I could get the Porsche one today but have to wait until next week most likely for the Bosch
In regards to the alternator, does the Porsche one have magic dust in it? Its freaking $1,200 where the 150amp reman Bosch is $269.
#32 - https://www.porscheatlantaperimeterp...rimLevel=18177
https://www.rmeuropean.com/Products/...6-efaf80cb153d
Unfortunately I could get the Porsche one today but have to wait until next week most likely for the Bosch
#15
As Stephan said — never disconnect the battery from a running car — never.
The battery tempers the DC voltage both in level and in noise. The latter contains spikes and other hideous things that damage electronics.
The battery tempers the DC voltage both in level and in noise. The latter contains spikes and other hideous things that damage electronics.