OBC Test Functions

[Alexlind123]

I unlocked my obc a bit ago for some fun and when i entered the test number for "Voltage at Terminal 4" It showed 11.54 with the key in the on position with the engine off, 12.82 with the engine on. Could this be indicative of battery failure? The engine has been starting with about 1.5 seconds cranking from a cold start (hot or cold ambient temperature, shows no signs on lengthening in the time i have driven the car). The battery is not original. I noticed that if i started the engine, let it run for about 30 seconds, thenm turned it off and put the key immediately in the on position, the voltage showed over 12 and when i started it it started much more easily than usual. I know that this could indicate a bad fuel pressure check valve, but with the voltage indicator it just makes me wonder.

[632 Regal]

13-13.5 while running is around the normal range while running. Check the alternator ohm output too.

[High Compression II]

I unlocked my obc a bit ago for some fun and when i entered the test number for "Voltage at Terminal 4" It showed 11.54 with the key in the on position with the engine off, 12.82 with the engine on. Could this be indicative of battery failure? The engine has been starting with about 1.5 seconds cranking from a cold start (hot or cold ambient temperature, shows no signs on lengthening in the time i have driven the car). The battery is not original. I noticed that if i started the engine, let it run for about 30 seconds, thenm turned it off and put the key immediately in the on position, the voltage showed over 12 and when i started it it started much more easily than usual. I know that this could indicate a bad fuel pressure check valve, but with the voltage indicator it just makes me wonder.

I hope to fit an OBC to my e34, What do you mean, by 'Unlock' your OBC?

Does this give extra test-functions such as voltage measurement etc??--Sounds like something good to have!

Regarding battery voltage, a battery fully charged, with NO load at all should show around 12.2-12.6V after having stood with no current drawn since last charge within 24 hours.
With all the electronic systems drawing a small current over a period of hours, like alarm systems clocks OBC's etc.etc. this will remove the 'surface' charge, and will leave you with around 11.9 v to 12.1--Add to this, the current drawn by the OBC and other systems while the ignition is on without the engine running, will drop voltage easily down to 11.5v Add to that, the resistance of the wires connecting the OBC to the battery (there must be several meters of it between the OBC and the battery!) 11.2 sounds a great value of voltage to have! Another point is, How accurate is the Voltmeter function 'Locked up' in the OBC??

Engine running with fully charged battery in good condition should be around 12.9-13.7V

[Javier]

check voltage with engine on, after a wile from starting (To allow battery to get some lost charge, and get a steady state in the alternator). I get a reading between 14.09 and 14.25 in my 535i.

If you are keeping 12.82 volts with engine running, I would say voltage regulator is a little weak.

Javier

[shogun]

High Compression II:
OBC unlocking, pls use the search:
http://home.iae.nl/users/bts/obc.htm

With 11.2V you will have a lot of problems, the engine will go into limp mode and you will see a lot of funny flickering on the cluster and alarms.