Update: I managed 145 miles before needing another charge, when I connected I had 16% battery left. Please note that I’m happy with this range as it is what I expected, especially with motorway driving. But it goes to show how broken my GOM is.
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Hi Folks,
Still this myth of GOMs with fixed rigid 4.7 efficiency assumption lives on. Sad really...
Let's use the above data from
@lee graham to bust this myth that the GOM works by assuming a fixed efficiency of 4.7
1. The current journey data shows efficiency of 4.7 at one point in the journey but later shows efficiency of 3.8
If the efficiency was fixed it will show 4.7 throughout. The data shows how the how system is self-updating and efficiency value in current journey is summative for the current journey up to the point in the journey where the reading was taken. As you can see at second point in journey the current data clearly shows 3.8 and is not fixed at 4.7 kWh per hour. If one were to go by the ridiculous rigid calculations that some have been using then at 3.8kWh the GOM should have been showing 161 miles at the start of journey.
2. Let's do more ridiculous maths....
If the GOM works on a simple addition, subtraction, multiplication, division bases like some want us to believe and the battery @16% is showing 39miles remaining, then at 100% it should have shown 244. Note at the start we are told it showed 215miles.
3. Also 145 to point of charge plus 39 remaining equals 184. This is not the 215 reading at the beginning.
Clearly the workings of the odometer is not based on simple multiplication and division or addition and subtraction maths.
One can continue doing further addition, subtraction, multiplication and division and things will never add up. Does that mean the odometer including the GOM is broken? Of course not.
Simple addition and subtraction basic maths will never work because rate of discharge of a battery is not linear and temperature and all the driving conditions that affect the GOM calculations vary considerably and also tend to be non linear.
Well....
The true situation is that we have 3 data sets in the odometer
1. Accumulative data..
This is the summative efficiency data from time of last reset of odometer to time reading is taken. This data tells one solely of the past and is self updating.
2. Current Journey data..
This data is summative from start of current journey to the point where reading was taken. It tells you about the current journey so far and is self updating.
3. The GOM... Distance on remaining charge.
This is the forward predictive section of the odometer. It tells you how far one may travel with the remaining charge in the battery if the driving conditions in which the car has been driven for the last X miles and/or Y minutes remains the same. It is self updating and not fixed on a rigid efficiency value.
The GOM is dynamic and its value is dependent solely on data from the most recent travel.
For example if you drove 40miles or 60 mins yesterday, then you charge your car overnight and switch it on in the morning, the odometer uses data from only the last X out of the 40 miles / last Y minutes out of the 60mins of yesterday's journeys and the immediate battery SOC to give you its first GOM reading. It then immediately starts to self update with today's driving conditions and today's battery state of charge as you drive along. It then continuously self updates mile by mile or minute by minute in keeping with your most recent X miles or Y mins of driving.
Because almost every factor that affects the GOM value in mathematical terms is exponential and there is complexity of correlations between the various factors, simple addition, subtraction, multiplication and division will not work if one tries to work out a GOM value by themselves.
Unfortunately as you can see there are people who deem themselves more knowledgeable than the whole of the EV industry and the makers of the odometer technology and such people will try with their basic maths to make all sort of conclusions. All such conclusions will be wrong.
So please do not get confused by those who continue to claim their GOMs work on a rigid fixed basic multiplication formula with a fixed efficiency of 4.7
GOMs are not designed to work that way.
Some also think the GOM is designed to give a minimum achievable distance no matter what. Unfortunately that is also not true.