Quick drop in charge when car is started

[GroundHog]

I have noticed that my % charge display on the dash drops very quickly when I first drive the car after charging, and then levels off as I drive farther. This doesn't seem to matter whether I charge to 100 or to 80. With no climate control on, The following is fairly typical:
80% 0 miles --- mi/kWh (battery temp of 52 F)
79% 0.1 mi --- mi/kWh
78% 0.9 mi 2.7 mi/kWh
77% 1.6 mi 3.7 mi/kWh
76% 2.0 mi 3.3 mi/kWh
75% 2.8 mi 3.5 mi/kWh

Is this what others see?

Even if I was driving horrible backing out of the garage and down my street, which I can't imagine, these numbers don't add up after what should be slightly more than 1 kWh consumed. In fact my Leaf Spy tells me 1.1 kWh consumed at this point. So where is the missing energy?

I have also seen the same thing happen when I charge to 100% and the charger stops. Then I start it again a few more times just to make SURE that I am really at 100%.

Is there something going on at the start of the discharge cycle just to get things going? I know that in my Prius, I get bad mileage for the first few miles because the engine has to be on to warm up. But I don't see what would be happening with the Leaf.

 

[smkettner]

You mean GOM miles? :roll:
Mine typically goes down 0 to 2 miles my first 10 miles. Must be easily confused by the small hill I live on.
Then it drops rapidly(faster than miles driven) down to about 20 after which it seems fairly accurate in normal circumstances.

Typically GOM is pretty optimistic at the start. Your readings are probably normal.

 

[GroundHog]

These are real miles driven in the 2nd column. I added the GOM readout in the 4th column:

80% 0 miles --- mi/kWh 68 miles
79% 0.1 mi --- mi/kWh 68 miles
78% 0.9 mi 2.7 mi/kWh 66 miles
77% 1.6 mi 3.7 mi/kWh 66 miles
76% 2.0 mi 3.3 mi/kWh 66 miles
75% 2.8 mi 3.5 mi/kWh 66 miles

 

[johnrhansen]

you are lucky you even see 80 percent. The charger kicks off as soon as it sees 80 percent, so you end up right on the edge. It doesn't take long before it goes to 79 just sitting there. Most mornings I get to my car it shows as 79 percent. That explains the fastest drop in your chart.

 

[Graffi]

I see this also, but I have a short downhill a few houses, maybe 60 yards, then slight uphill for maybe 1/2 mile, flat for 1/2 mile as the m/kwhr slowly goes up, then start a 3 mile steady downhill, with a couple of short rises. It takes 4 miles to get to the freeway and I am usually at 8 or 9 m/kwhr by the time I get to the freeway ramp. On carwings I am usually in low 100's each month for regen. One month I was 96, so I finally made the top 100 list.

 

[GroundHog]

you are lucky you even see 80 percent. The charger kicks off as soon as it sees 80 percent, so you end up right on the edge. It doesn't take long before it goes to 79 just sitting there. Most mornings I get to my car it shows as 79 percent. That explains the fastest drop in your chart.

This is what I had always thought, that the quick loss of about 5% total was not really 5% due to round-off and perhaps some type of effect as the battery switches from a 'charging' state to a 'dis-charging' state.

But now that I have Leaf Spy, I'm wondering again. Because the Leaf Spy is reporting that during this 5% drop, I have actually used just over 1kWh. That would be a real 5%. So if I have really used 1.1 kWh to drive only 2.8 miles (net downhill at neighborhood speeds), the mi/kWh should be reading 2.6 not 3.5. All this assumes that the Leaf Spy is giving accurate readings for kWh consumed which I have no idea how it does this or what its based on, AND that the mi/kWh display on the dash is accurate.

 

[johnrhansen]

in the winter, a big thing is the initial high draw to warm up the car. When it gets really cold I'm down a a few percent before I even go a mile. My efficiency goes as low as 1.5 miles per KW before I get on the freeway.

 

[GroundHog]

in the winter, a big thing is the initial high draw to warm up the car. When it gets really cold I'm down a a few percent before I even go a mile. My efficiency goes as low as 1.5 miles per KW before I get on the freeway.

This makes total sense if you are referring to running the climate control to warm up the car. But that's not what I'm doing. It has been chilly lately, but I try not to use the climate control, and the numbers I posted were on a day that I didn't use the climate control until the very end of my trip. Also when the climate control is used, as you say, its effect is factored into the reported miles/kWh. This is perhaps my real issue... Why is the reported miles/kWh on the dash different from the actual miles driven divided by the actual kWh consumed as reported by Leaf Spy? By the end of my trip, these two numbers are only off by less than 0.1 miles/kWh (round-off error).