So when returning from Iowa City to northern Suburbs, we were drenched. I had not yet driven in Plus in heavy rain on the highway before, certainly not for extended periods of time.
I have done this trip a couple times now, so usually, on the 225 miles, I can average low 4's at around 65 mph average (I did punch it on the way out, and at 70 for good distances ended up with 4.0 miles per kWh). Now I do stay with set set of traffic, and will go a bit slower if by myself as the wind resistance will quickly eat into my efficiency.
So in the heavy rain (even in medium rain), the impact of rain was significant. In the heaviest of rains, due to visibility, I was only going about 40 mph and was only getting about 3.5 miles per kilowatt. I had not anticipated getting such a large impact to efficiency.
We were lucky in the end, as between Dekalb and Aurora the rain lightened giving back a bit of efficiency, We were going to stop at the EA charger off of 355, but then the rain stopped and efficiency improved again.
As we moved on to 294, because weather patterns were moving quickly north and east, we had an unbelievable tail wind. I sometimes feel like driving an electric car is more like flying a plane then driving a car. I had never seen such amazing efficiency on the highway, for the 18 miles, between the end of 88 and 294 we averaged over 5.3, at 60 mph... It was truly unreal to get that type of efficiency. (maybe normal for Tesla 3's, but crazy good for us Leaf drivers when not driving downhill).
I ended up rolling up with 5 kilowatts left on Leafspy which was much less close then I thought due to the amazing tail wind. It never even hit very low battery (though very close). 1% showing on the dash for the last 6 miles. I sometimes think Nissan made a mistake by leaving so much range under 1%, as the car reviewing places tend to discount it. I think i had close to 6 kilowatts or 10 percent when dash went to 1%. In the few videos I have seen, it seems Tesla only leaves a couple miles of spare at the bottom of gauge. While I know this prevents getting stranded (in fact has anyone heard of anyone getting stranded in a plus), it gives a more negative perception of overall range.
Battery temp was about 87 F when we left and about 94 F when we pulled into the garage. Ambient temps were between 73 and 76 F. Temp was flat at around 91 for much of the trip until the battery was very low, and crept up the the last few degrees only in the last 15 minutes. I am guessing the rain with slower speeds for the mid section kept temps in check. Usually it creeps up a bit more during these 4 hour drives on a charge.
The good news is the Michelin Defenders did really well in the rain, even at 44PSI ,and traction on the roads, even when driving through mounting water was very good.
I think it was Olympia Dave that said rain is your biggest impedance to efficiency, and I would have to agree after this run. 25-30% impact to range in the downpour. When you consider even at 40-45 i was only in the mid 3's.
2019 SV Plus Silver
2013 Leaf SV
100 Mile Club Member (Number 87)
Max distance on 13 Leaf: 120 miles
Max distance on 19 Leaf: 242 Highway 4.5 miles/kWh (4.9 KWh remaining)