What is your miles/kWh (total average electricity consumption) on the "Drive Monitor 2"

On my 2017 PRIME, I put 40K miles in 2.5 years and the lifetime average was 5.2miles/kWh. But this includes very intensive manipulation to increase EV efficiency in the last 8 months of the ownership. At the end of 2 full winters at ~30Kmiles, I had 4.5miles/kWh. If I did not change the way I drove, the number would have stayed at around 4.5 miles/kWh all the way to the end. The first 10K miles is easier to change the lifetime average, but longer you drive harder to change the average for the lifetime miles/kWh. I traded in 2017 Prime to 2020 Prime at the end of Feb. Since I now have only ~500 miles on my car, my DM2 miles/kWh fluctuate daily between the min 0 miles/kWh when I reset DM2 data to max 99.9miles/kWh. It is currently showing ~15miles/kWh. This is with EV/HV switching to maximize EV efficiency.

 

Update on my 2020 PRIME. After 1000 miles on ODO, I am now recording over 20miles/kWh on the DM2 which was reset shortly after I purchased the car new. The car had 40 miles on ODO when I purchased it, but there was no record that it had ever been driven EV mode with a charged traction battery. All miles driven were accounted on the Eco log, but corresponding miles/kWh was all 0.0 indicating that no EV mode was used for those miles. Yet, DM2 was showing 5.3miles/kWh when I took the delivery. I have reset the DM2 to check if the number represents the base number where the record starts, but that was not the case. Immediately after the reset, the DM2 was showing 0.0 miles/kWh. So I don't know how initial 5.3 miles/kWh was generated without any EV mode drives.

In any case, since then I have been trying to keep the EV efficiency high by using EV mode only in very low demanding portions of my trip, namely on downhill, flat road coasting, and very light accelerations. This has resulted in DM2 recording above 20 miles/kWh. However, my current GoM for a full charge is just slightly over 30 miles mark. If GoM is calculated simply from average miles/kWh, it should show much more than 30 miles, but it doesn't. What can be concluded is that the GoM must use other parameters besides just average miles/kWh. But I don't know what other parameters are???

 

If I can put numbers and formulas on that common sense, then I will be satisfied with your answer. I am just curious how GoM mile is calculated internally in my car. That's all.

In my current, ~50 miles per week driving and very low cost of gas (about 40% lower than electricity for the same distance), it is the best time to experiment those parameters.

 

That's very good to hear. Since I traded in my 2017 Prime, I am starting out a totally new matrix. I plan to keep a record of kWh required for a full charge, unlike I neglected with my 2017 for over a year during my ownership. But currently, I am not driving my 2020 PRIME much, and I don't want the car to just sit with a full battery charge. I have charge my traction battery fully charged from empty only twice so far. Both times it took ~6.5kWh. I think the slight variation on the full charge amount comes from the amount of discharge after the traction battery reaches 0% before starting to charge and also the ambient temperature. But I don't have any hard data to support this theory.

 

That's too close. Maybe the battery temperature was different?

 

I just did a full charge on my new PRIME today. The full charge took 6.92kWh measured by Kill-a-watt meter. I run out of EV range just a few hundred feet before pulling into my driveway yesterday, so I did not over-discharge the traction battery after EV range was depleted. This was probably the highest amount of kWh used for a full charge in my recollection. I really don't know what's going on.

 

I wish I had the Hybrid Assistant running the last time I depleted the EV range. If I did, I could tell what SoC the hybrid battery was at the time I parked my car.

For the record, on 2017 Prime, the number of times I did check the EV range depleted traction battery SoC, it ranged from 10.2% to 14.12%, but this is not precise 0% EV as you have measured. A varying distance of HV drive after depleting EV range caused the variation. More interestingly, the 100% SoC on the dash corresponds to a much tighter range from 82.35% to 83.92% but did show some variability. Low mark on 0% and high mark on 100% might explain more kWh used for a "full-charge", but that's only speculation at this point.

 

Aha! The cooling fan might be the reason for the increased kWh. Due to the COVID-19 situation, I am not doing nightly scheduled charging now. The car was parked over night since last driven on Sat, but for yesterday (Sunday), I just did the immediate charge by plugging in at 10:30am. I don't usually charge my PRIME during day. Yesterday high temp was 76F. Even though the car was parked in a shade I am sure the inside of the car was above 80F. Compared to this, our night temp even during hot summer is usually 50-60F and inside of car is as cool as ambient temp. As far as I can remember, this was the first time I charged my PRIME from zero to full during a summer midday.

 

Wouldn't that shows up on the SoC matrix on HA? At least for my 2.5 years of owning 2017 PRIME, the real SoC on the traction battery was always corresponding to 84% to 14%.

 

I understand what you are saying, but to be honest, I do not have enough knowledge about the lithium battery chemistry and physics to understand how the "capacity" of the battery can be degraded without change in voltage. At least for the 12v lead-acid battery, the voltage measurements and overall capacity (State of Charge SoC) seems to be direct relation, at least that is what I have learned from reading several 12v battery maintenance threads. If the lithium battery is somehow different, I don't have a clear grasp of what constitute the degradation and how it happens.