battery check and OBC 9 test reading question, please

[nariusb]

Hi,
I checked my battery with DMM it shows 12.20V and also I took a OBC test 9 reading and it says 11.79 UB.
Shouldn't those be identical? If, yes then where do I loose that voltage?
Thanks guys

[Bill R.]

margin of error might be that much or your obc margin of error could be that much. Or if your battery terminals have any corrosion at all on them the resistance increase could be enough that the obc would read off... assuming that you stuck your leads from your dmm directly on the battery posts



Hi,
I checked my battery with DMM it shows 12.20V and also I took a OBC test 9 reading and it says 11.79 UB.
Shouldn't those be identical? If, yes then where do I loose that voltage?
Thanks guys

[Qsilver7]

Bill, could there possibly be more drain on the battery when you perform TEST #9 versus using the DMM on the battery posts?

Let's see, using the OBC (TEST #9), the door may be open and interior lights on, and when you turn the ignition to position 1...what else has powered up and drawing power from the battery (since the engine isn't running...thus not recharging the battery). This may account for the different reading...just a thought.

[nariusb]

Hi,
I checked my battery with DMM it shows 12.20V and also I took a OBC test 9 reading and it says 11.79 UB.
Shouldn't those be identical? If, yes then where do I loose that voltage?
Thanks guys

Where does OBC look at the DC exactly? I can't get a reading that way above 12v ever. Does this mean the battery is dying? I do get a battery light ON for a second at the startup and cranking could be shorter too. I wonder if that's related at all.

[Bill R.]

door would be open and the lights on, but i didn't consider any other draws when the key is on such as the ventilation system fan or anything else that gets energized.. thats a good possibility. He could also check it up front at the jumper cable contacts and see if its lower there than directly at the battery which would imply resistance in the battery cables somewhere.




Bill, could there possibly be more drain on the battery when you perform TEST #9 versus using the DMM on the battery posts?

Let's see, using the OBC (TEST #9), the door may be open and interior lights on, and when you turn the ignition to position 1...what else has powered up and drawing power from the battery (since the engine isn't running...thus not recharging the battery). This may account for the different reading...just a thought.