But some feel that E-Pedal uses friction braking too much which lowers efficiency. Now, how they got this idea is anyone's guess. E-Pedal does use friction braking if the SOC is high, E Pedal will engage more friction braking in order to minic E Pedal at lower or "normal" SOC levels but for the most part, friction braking is used primarily at VERY low speeds.
Well, it became quickly apparent that just saying E-Pedal is better wasn't going to work. People simply got it in their heads that certain things were happening and and that was that so this is my attempt to "data dump" naysayers into submission!
So armed with a good charge (75% is highest SOC my LEAF has seen in months) Fully charged LEAF Spy phone (and LEAF Spy of course) off I went.
Now the first thing we need to know is that LEAF Spy on your phone changes rather slowly. You can see this by watching power output. Take your foot off the E Pedal and the motor power should show regen. The delay from the pedal movement to the LEAF Spy screen is significant. a few seconds. Depending on timing of that delay, it can be hard to get values especially when we are only looking for max values and with regen levels we are expecting, max values will only last a few seconds unless going down very steep hills. So several runs will be needed to determine a good close approximation. Then the best course is downloading and reviewing the log files which can be opened in any spreadsheet program. This allows sorting of any value which makes gathering peak values quite easy.
To lessen the possibility of errors, I decided to do this over several days hoping for different temperature ranges to see if they had an effect. I also QC'd before each run to heat pack at least into the low 80's. Was aiming for the upper 80's but one day, pack started at 51º and temps basically stopped rising about 75% SOC so had to settle for low 80's. Close enough, I think.
I also separated the E-Pedal runs and Eco B mode runs into separate days as well. So if LEAF Spy's granularity is so poor, why use it? Well, the ability to download the data and sort in a spreadsheet is obvious but if that isn't enough consider...
We have a power meter on the dash that shows power or regen and like most Nissan instrumentation, it should be ignored. Ok, maybe that last statement was a bit over the top. There is a small meter that is visible on most screens that has 8 regen segments and 16 power segments or we can use the dedicated screen that doubles the segments for both. Should be enough, right? WRONG!
Well... maybe not "completely" wrong as long as one understands the meter uses different scaling for each drive mode. In retrospect I do understand why people might think E-Pedal uses a lot of friction braking because everyone knows the slowdown in E-Pedal is much more severe than B mode but what if they found out that E-Pedal's regen has a 50% higher ceiling?
We all know E-Pedal slows the car dramatically faster than B mode does although B mode does a pretty good job as well, just not quite as fast. If there is a slight upwards slope to the road, B mode will slow the LEAF to nearly a complete stop. But creep will allow the car to continue to... well, creep. Sadly, even E-Pedal has creep enabled. Creep power is small, roughly 200ish watts or so but even at a standstill, E-Pedal is still using this 200 watts just like D mode, B mode, and likely reverse (You will have to check on that) but at least "friction braking" still brings the car to a full stop.
Now both E-Pedal and B mode do quite well with moderated regen. And this is how most (including me) drive 90% of the time. Its gradual slowdowns mixed with shorter more aggressive deceleration. So all this is dealing with the remaining 10% where speeds are much less predictable due to traffic, controls, crazy drivers, etc. So the target of the test is finding out why E-Pedal slows faster.
I did several runs using B mode only (no braking) at high speeds on steep downhill slopes in order to hit max regen as long as possible. After collecting several data points, the best B mode could do was 36.8 KW. Below is an edited version of LEAF Spy logs. No values were changed. I simply removed extra fields that do not pertain to the topic for clarity.
After several people contended that friction braking is enabled in E Pedal even at higher speeds, I have begun a test of efficiency that will last several weeks. Since I am not going to just "drive around" in a circle or any other type of attempted close course, I can only average my results over an extended period of time. I did start the testing before the weather got warmer and drier but did miss the colder part of the year so will be adding that later this year but will be posting at least initial findings when I have enough "hot weather" data collected so stay tuned.
It does look like the easiest method for efficiency is B mode for most driving using E Pedal for rapid slowdowns and full stops. This does not change the fact that E Pedal is still a dream come true in stop and go traffic!