Confusion about Scanguage voltage reading
#1
03-23-2018, 10:25 PM
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Confusion about Scanguage voltage reading
My question is: Are the voltage readings taken from the batteries, or from what the alternator is putting out? I'm speculating that when the engine is not running, the readings are from the batteries, but when running, the readings are from the alternator, indicating how much voltage the batteries are calling for.
I don't possess much knowledge about electric/charging systems and am attempting to clear up some grey areas in my brain.
Thanks,eh?
Brad
I don't possess much knowledge about electric/charging systems and am attempting to clear up some grey areas in my brain.
Thanks,eh?
Brad
#2
03-24-2018, 02:16 PM
Brad,
When I check my system voltage off of the OBD connection under the dash with my DashBoss, I see 1/2 to 3/4volt less then actual "system" voltage due to resistance loss. Instead of trying to specify whether battery or alternator, the system voltage will basically read battery voltage when not running. With the engine running the system voltage will increase while charging. You can see a difference, with a vom, between the rear alternator terminal and the batteries, again due to resistance loss. Expect to see 13.8-14.4v at the alternator, slightly less at the batteries, knowing it will vary due to battery charging needs.
I always check my batteries after sitting overnight to get a good static reading. Expect good batteries to be between 12.6-12.8 volts.
I hope that helps, not confuses you more.
When I check my system voltage off of the OBD connection under the dash with my DashBoss, I see 1/2 to 3/4volt less then actual "system" voltage due to resistance loss. Instead of trying to specify whether battery or alternator, the system voltage will basically read battery voltage when not running. With the engine running the system voltage will increase while charging. You can see a difference, with a vom, between the rear alternator terminal and the batteries, again due to resistance loss. Expect to see 13.8-14.4v at the alternator, slightly less at the batteries, knowing it will vary due to battery charging needs.
I always check my batteries after sitting overnight to get a good static reading. Expect good batteries to be between 12.6-12.8 volts.
I hope that helps, not confuses you more.
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