Recent content by Gonville

Is this also because you have very moderate temperatures? We have below zero centigrade frequently in winter and folks routinely get a failure if they have left the car for a week at Christmas/end of year holidays. If the 12v is already weak I guess that can kill it off more frequently. I...

Pretty sure it isn’t activating the DC-DC charger unless the car is ‘on’. Easy to leave it in that state but opening the door makes it go to off - of course it stays on if you clip the seatbelt in (behind you) as it still thinks you are safely in the car. So with it ‘off’ but the rear open...

I had this message come up once with my 60Ah - I was moving house and was packing the last things into the back with seats down. Car doors were open but car was switched off. State of charge was not recorded but must have been high as we were about to drive to the new location (170 miles)...

I disagree. There is no BMW technical data that supports anything other than plug the car in. This is for an i3. i4 is different as are all the other i models none of whom use the refrigerant cooling. Even the Mini SE has same drive but different glycol based cooling. There is evidence to...

Worth reading what aloha has said about the accuracy of the capacity reporting of the various apps.

I think like all these discussion disagreement requires proof. Battery university has all that and unfortunately it all related to single cell with no thermal management and no BMW safe guarding deep discharge etc etc etc. I leave the reader to Google.

Yes I believe BMW told us at that meeting that it was around 85% indicated. They didn’t want to impact range on the very small battery below that level. We have used that ever since although I have never found that identified in any workshop manuals.

I agree on a lot of this but the practicalities are not quite how asserted. Again it is battery university, single naked cell, no deep discharge protection, no overcharge management, no thermal management, 1C charge and discharge. We don’t have that. - Calendar degradation - yes nothing...

First - I like the logic but the 10% buffer was at the top in the early models. So that negates most of what is calculated from there on. Current models are different I agree. Second - if you don’t charge higher there will not be cell balancing. I can’t see how that fits with the argument...

We think the level at which cell balancing doesn’t happen is 85%. Yes I did meet with engineers in UK - we had a mega meet at Farnborough BMW HQ. Was very informative. Pictures I took at that session are in David Bricknell’s excellent book. I suspect as we have had only 1 or 2 documented...

Cell balancing also is passive top end. That only happens on completion of charging when the level is above 85%. Indicated. If you only charge to 80% indicated the cells will become unbalanced and a reduction in charge capacity and therefore range will occur.

Calendar degradation occurs irrespective of charge level. Thinking that a low level of charge which save on degradation is naive at best and misleading at worst. Calendar degradation is what it says. 1-2% per annum irrespective of charge level. Also BMW engineered a refrigerating cooling...

This ignores the fact that there is a top end ‘reserve’ not available which prevents charging above 85% actual? So unless one qualifies the remarks about ‘100%’ that advice in itself is worthless. The manual used to state leave it plugged in and there was no system iDrive mechanism to ‘stop’...

I remember that. They have a guy who does it but it’s only economic in batches. So they wait until they have 20 and then send them off for resoldering. It’s about 10:17 into this video under the ‘Internal’ section. Doesn’t show repair just explains that the LEDs need replacing as they are...

The 12v is charged when the HV is being charged. Could be why the poor things are dying if they are not left plugged in at least some of the time and mileage is relatively low?