cezdoc
Member
I have a Model S so may not apply to the MIC M3LR but the following has given consistent results over 5+ years and multiple software updates:
Without using 3rd party apps I can get two measures of capacity: one for charging and one for discharging.
For charging capacity, as suggested above, if you can measure (meter) how much kWh is needed to add, say, 50%, to the battery SOC (state of charge) you can extrapolate to 100% to get the energy needed to fill the battery. Doing this over several charge sessions and taking an average/doing a line fit on a spreadsheet would give a more accurate estimate. If AC charging the current (10A / 16A / 32A) makes a noticeable difference with the highest current being most efficient.
For discharge, if you note the % before setting off on a long, non-stop (i.e. don't leave the driver's seat so the car doesn't power down) trip the "since hh:mm" trip info can be used. E.g. depart at at 80%, arriving at 30%, 100 miles covered, 320 Wh/mi. Total energy used is 100*320/1000 = 32 kWh (so useable battery capacity is 64 kWh). If you set off immediately after charging then the "Since hh:mm" and "Since last charge" stats will tally and confirm the total kWh used. Again multiple long trips allow a more accurate estimate to be made - they should all plot on a straight line (energy vs. change in SOC) (if there is no measurable battery degradation over the period).
Finally as a way of measuring degradation look at the battery range in miles vs %. E.g. miles at 90% will gradually decline over time as the battery loses capacity. Rated miles corresponds to actual battery capacity. In my case (MS 70) 90% = 191 mi whereas when it was new 90% = 202 mi. You can calibrate the rated miles to kWh using the trip stats: for my car it works out at 1 rated mile = 287 Wh. This has stayed fixed over multiple software updates and the changing seasons.
I recall there may have been a bit of headroom above 100% on brand new cars (i.e. it was possible to add a bit more energy even when the SOC = 100) which helped to hide some initial degradation, but unless you charge to brim full you're unlikely to be affected by that.
Without using 3rd party apps I can get two measures of capacity: one for charging and one for discharging.
For charging capacity, as suggested above, if you can measure (meter) how much kWh is needed to add, say, 50%, to the battery SOC (state of charge) you can extrapolate to 100% to get the energy needed to fill the battery. Doing this over several charge sessions and taking an average/doing a line fit on a spreadsheet would give a more accurate estimate. If AC charging the current (10A / 16A / 32A) makes a noticeable difference with the highest current being most efficient.
For discharge, if you note the % before setting off on a long, non-stop (i.e. don't leave the driver's seat so the car doesn't power down) trip the "since hh:mm" trip info can be used. E.g. depart at at 80%, arriving at 30%, 100 miles covered, 320 Wh/mi. Total energy used is 100*320/1000 = 32 kWh (so useable battery capacity is 64 kWh). If you set off immediately after charging then the "Since hh:mm" and "Since last charge" stats will tally and confirm the total kWh used. Again multiple long trips allow a more accurate estimate to be made - they should all plot on a straight line (energy vs. change in SOC) (if there is no measurable battery degradation over the period).
Finally as a way of measuring degradation look at the battery range in miles vs %. E.g. miles at 90% will gradually decline over time as the battery loses capacity. Rated miles corresponds to actual battery capacity. In my case (MS 70) 90% = 191 mi whereas when it was new 90% = 202 mi. You can calibrate the rated miles to kWh using the trip stats: for my car it works out at 1 rated mile = 287 Wh. This has stayed fixed over multiple software updates and the changing seasons.
I recall there may have been a bit of headroom above 100% on brand new cars (i.e. it was possible to add a bit more energy even when the SOC = 100) which helped to hide some initial degradation, but unless you charge to brim full you're unlikely to be affected by that.