Thanks for the reply mate... ok, so with the headlights on (LED's) and the hvac fan on high the voltage at the battery dropped to 10.9V.

From comments earlier in this thread it seems like I'm needing a decent charge into it.

Cheers

Yeah, sounds like it might come up OK with a decent charge. Still, with a resting voltage of a tad over 12v, the BMW charger should be OK. Have you tested the BMW charger on another battery, just to eliminate a faulty charger?

Got a local battery world outlet so went and had a chat... they reckon the charger won't initialize because the battery is too far gone...

$278 for a new battery fitted and coded or $200 for another charger that will handle the charge....

I'm gonna get them to load test it but sounds like it might be time for a new one...

$278 for a new battery sounds good - closer to $400 here... :thumbup:

And forget the "coding" - there is no battery coding on an E53 - unless you (they) are referring to coding something else (not related to the battery). :confused:

FYI: just to reiterate whats been mentioned several times...the E53 battery DOES NOT need to be coded.


If you end up replacing your battery with a new one...and you get told/charged with coding/registering the new battery...DO NOT fall for this. It doesn't apply to your e53 because it doesn't use an IBS (intelligent battery sensor) and neither do you have the LIN or BSD bus.

The IBS started with the new generation BMWs...and the early new gen BMWs (like the e65/e66/e90) that didn't have an IBS but do have the newer LIN & BSD communication bus...requires battery registration/coding.

Cheers for that QS....my bad must be my memory from having an E70 that needed doing..

Well, went out to the garage this morning and she's officially dead, not even a click... guess I now know the answer to the battery status...

Off to spend some money :thumbup:

Open Circuit Voltage Approximate State-of-Charge at 80°F (26.7°C)
12.65 100%
12.45 75%
12.24 50%
12.06 25%
11.89 or less DISCHARGED