Only 18 KWh Usable Energy for MY Leaf--Retest Shows 20.3 KWh

TickTock, thanks for posting this. I was going to do a similar graph with my SOC meter, but you saved me the trouble. I expected more of a shoulder at the top end, though.

If you can send me the logs, I'd be happy to generate the plot. I think it would be good to get another set of data from a more "normal" battery since mine seems to be an outlyer.

Thanks Tick
Not a good idea discharging past the first warning.. the fact that so many people do it routinely means Nissan is doing a very good job matching cells. Will the cells remain matched as they age?

Stoaty,
If you prefer, I posted some perl code here if you want to save some time figuring out the log format:

http://www.mynissanleaf.com/viewtopic.php?f=44&t=6088

I'm using strawberry perl and notepad++ (both free).

One more datapoint. I also integrated the battery_volts*battery_amps*delta_time during the charge from 28 gids to 100% (244 gids). I got 18.2kWh actually going into the battery. My wall power meter read 19.9kWh for the same charge cycle. This comes to 91% charging efficiency. We've pretty consistently been coming up with ~85% total efficiency using the miles_driven/dash_efficiency compared to the wall power. So it looks like the driving efficiency is about 93%. Given the error bars, I'd call it ~92% efficiency each side. Some pretty good engineering on Nissan's part.

Awesome data, thank you for sharing all this!

Truly great data! Thanks!!

Thanks to garygid for for providing the hardware and support!

Thanks.
A means of getting good data into the hands of the technically
curious (and capable) was one of my goals.

As interest grows, I hope we will have many good insights.

One more observation. I graphed the change in energy vs gids and the resulting flatness I think confirms that the units are, in fact, energy (and not charge). This, of course, makes the most sense for predicting range. When I plotted versus charge, there was a clear curvature. Lots of variation (DNL) but the average step size is 0.085kWh for my battery.

TickTock -- good graphs! How are you sampling the battery pack voltage?
Being able to match these to dash indications and SOC units is very useful information.

It is based purely on the "Li-ion battery voltage signal" transmitted from HVBAT to EV/HEV on the EV Can bus. I am trusting Nissan's measurement is reasonably accurate.

TickTock said:

One more datapoint. I also integrated the battery_volts*battery_amps*delta_time during the charge from 28 gids to 100% (244 gids). I got 18.2kWh actually going into the battery. My wall power meter read 19.9kWh for the same charge cycle. This comes to 91% charging efficiency.

Click to expand...

This was with an L1 or L2 charge?

Herm said:

TickTock said:

One more datapoint. I also integrated the battery_volts*battery_amps*delta_time during the charge from 28 gids to 100% (244 gids). I got 18.2kWh actually going into the battery. My wall power meter read 19.9kWh for the same charge cycle. This comes to 91% charging efficiency.

Click to expand...

This was with an L1 or L2 charge?

Click to expand...

L2 (240V via AV charger).

I have noticed a large loss of range. I drive as you should know 76 miles 5 days a week. I charge 5 days a week to 100% and 80% 1 day a weeks as that is enough to drive the weekend. After the reprogramming I came home after my 76 mile RT from work I had as much as 15 mile on dash. Now I am coming home on (---) that's not good.

Stay tuned I will have more.

Gonewild said:

I have noticed a large loss of range. I drive as you should know 76 miles 5 days a week. I charge 5 days a week to 100% and 80% 1 day a weeks as that is enough to drive the weekend. After the reprogramming I came home after my 76 mile RT from work I had as much as 15 mile on dash. Now I am coming home on (---) that's not good.

Stay tuned I will have more.

Click to expand...

And you're certain the heater isn't turning on?

I have never used the heater. If the heater was on I would not make it home.

Do you think it's temperature related? Or something else?

soon as temps go below about 70º you will be affected. i lost more than 10% (please do not insult me with heater questions!!) due to a drop in temps from the mid to upper 70s into the low 60's.

nothing else has changed and that includes, type of driving (urban, no freeway) destinations, traffic conditions, etc. its only the temperatures.

i saw the same thing except in reverse in Apr/May of this year. now i know why

This makes me ask why even on cars equipped with a pack heater, it's activation set point is -4F ?

It then warms the pack to 14F

Reason , not to maintain range that's for sure, it drops when pack temps are lower than 65 or so


It's onLy
to prevent a no start or frozen pack condition, what a waste!