Why doesn't the OBC calculate avg speed correctly?
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From: Back in the Netherlands since July 2008
My Ride: 520d LCI, old engine, manual, black dakota, platingrau II, standard (242?) rims.
My wife drove my 520d for a day. This is what the OBC looked like after she returned:
In km and liters per 100 kilometers (the 'Belgian' way of presenting usage)

In km and kilometers per liter (the 'Dutch' way of presenting usage)

In miles and MPG (UK)

In miles and MPG (US)

I noticed that the stated time, distance and speed do not correspond to each other.
Driving 301 miles in exactly 6 hours makes an average speed of 50.2 mph, not 52.1.
(or, equivalently, driving 486 kilometers in 6 hours makes an average of 81.0 km/h, not 84.0)
Do others have the same experience?
BTW, the stated fuel efficiency statistics are about 10% off (actual efficiency is worse). I'm not complaining about the fuel efficiency, but would like to see more accurate figure. I plan to adjust the setting in the hidden menu after some more kms (only done 3100 on it now)
In km and liters per 100 kilometers (the 'Belgian' way of presenting usage)

In km and kilometers per liter (the 'Dutch' way of presenting usage)

In miles and MPG (UK)

In miles and MPG (US)

I noticed that the stated time, distance and speed do not correspond to each other.
Driving 301 miles in exactly 6 hours makes an average speed of 50.2 mph, not 52.1.
(or, equivalently, driving 486 kilometers in 6 hours makes an average of 81.0 km/h, not 84.0)
Do others have the same experience?
BTW, the stated fuel efficiency statistics are about 10% off (actual efficiency is worse). I'm not complaining about the fuel efficiency, but would like to see more accurate figure. I plan to adjust the setting in the hidden menu after some more kms (only done 3100 on it now)
Thread Starter
Members
Joined: Nov 2006
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From: Back in the Netherlands since July 2008
My Ride: 520d LCI, old engine, manual, black dakota, platingrau II, standard (242?) rims.
Originally Posted by Iceman' post='433157' date='Jun 7 2007, 03:10 PM
Where your wheels in motion the whole time during this trip? 

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Originally Posted by boukehj' post='433161' date='Jun 7 2007, 10:15 PM
Clearly not, but recall from earlier occasions (waiting in the car while my wife was shopping - good work distribution) that the average speed adjusts while idling.
I think it displays the driving speed only.
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Joined: Nov 2006
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From: Back in the Netherlands since July 2008
My Ride: 520d LCI, old engine, manual, black dakota, platingrau II, standard (242?) rims.
Originally Posted by qtrxist' post='434205' date='Jun 10 2007, 02:00 PM
quick noob question, what is the practicality/use of the average speed being monitored?
I am just surprised by the lack of accuracy of some aspects of my new 520d:
Fuel consumption: the car reports a figure that is around 10% too optimistic (compared with actual fuel consumption full tank to full tank)
Now this. It's not rocket science to calculate these figures (and I can have some understanding for a minor inaccuracy in fuel consumption, since it is based on sensory data).
Let's hope some other BMW engineer did the calculations on DSC, ABS etc ...
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My Ride: 2005 545i Titanium Silver Metallic / Gray / Steptronic / Sport Package w/ active steering, adaptive xenons, sport seats, 18" style 124 wheels / Logic 7 sound / PDC / Bluetooth / iPod Integration
Avg speed does include idling time.
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