I was recording ODB parameters for a 26-mile trip I made today and I was wondering how much regen I got. For some reason, it bothered me not to know how much difference regen makes. So the Car Scanner app has a data recording functionality that allows for the user to record all the parameters and then export them to Excel. Today I drove 26 miles and here are some interesting numbers: The trip was a mix of freeway and city driving and some waiting in the car (freeway speeds of around 65mph). The trip took 50 minutes and 14 seconds and covered 26.013 mi State of Charge at the start was 100% and 60% at the end. The car used 5.639189 KWh of battery capacity. It actually used 7.255261 KWh but it was able to regenerate 1.61607 KWh which resulted in the 5.63...KWh final number. That is ~22.3% regen which is higher than I expected. My trip MPGe was 155 when you include regen and 121 MPGe without it. The process to get these numbers. 1.) Recorded Data in Car Scanner app 2.) Exported it to CSV 3.) Created a graph and calculated the area under the curve (5.639189 KWh) 4.) Calculated the area under the curve for positive numbers (7.255261 KWh) 5.) Calculated the area under the curve for negative numbers (1.61607 KWh) Here are some pictures. Here is the State of Charge vs. Battery Power vs. Car Speed in Car Scanner: Here is the same in Excel: Anyways, not sure if this is interesting to anyone but I think 25% regen is realistic and makes a lot of difference.
That is way more than I expected from regen... never thought that will make a significant difference. Which scan tool did you use? Thanks for sharing!
This is great !! You will undoubtedly be interested in a similar test that I did earlier in the year to look at how effective regeneration is in minimizing the use of the friction brakes. You can see my results here: Click Here I assume you are using the Clarity profile in Car Scanner which also provides a lot of Clarity-specific parameters including Battery Capacity. We provided those PID's to the Car Scanner developer some time ago. There are a few more related to the A/C (Freon pressure) that are not in Car Scanner, but can be found in the Budget Battery Capacity thread.
@Aleksandar Mitrovic is using the Car Scanner App... I don't know which OBD2 adapter he uses, but I highly recommend the Vgate iCar (BLE4.0 version). It is around $30. You can see the reasons why in the Budget Battery Capacity thread.
@MrFixit So you helped get the parameters into Car Scanner. That is awesome work. How did you go about figuring out what they mean? We also have a BMW i3 and unfortunately, the people buying BMW's are not as obsessed as the pragmatists buying Honda Clarity's therefore Car Scanner data for BMW is limited. Thank you for all of your work on getting the parameters in. It is amazing! I did buy the Vgate iCar (BLE4.0 version). The only thing that I do not like about it is that in order to reconnect to the Car Scanner app I have to unplug it and plug it back in every time I start the car. Any tips on how to address that issue?
Yes, this is a power saving 'feature'. You can disable that, per these instructions: Click Here The Clarity PID's were obtained by sniffing the CAN bus while using a known diagnostic tool. It was a matter of decoding the binary responses in order to sniff out the bytes / bits in comparison to known good results.
@MrFixit This is awesome!!! I have done the same figuring out a protocol at my work before. That can be a big job. So, what is your next car after Clarity? I am not sure I want to have a car without Car Scanner PID's again. It is great for engineers to be able to measure that stuff!
I run them until they die !!! I hope to have the Clarity for 10+ years, so who knows what kind of vehicle may be available then. I am thinking a BEV of some kind.
Thanks @Aleksandar Mitrovic (Alex?) this is wonderful! Great read. Forgive me if I overlooked it, but I couldn't tell if you'd driven exclusively EV or perhaps HV. Your graph mentions "HV Power" so I suspect it's the latter (or a mix of both?). I've been thinking about this issue (battery regen) as I work on a spreadsheet to track my usage, and realized that I wasn't directly accounting for the "regen" that occurs (that is, recharging) during HV driving. Your calculations are a great inspiration. But then I also wonder: if you were driving in HV mode, it seems that some of your regen is due to slowing and braking, but then some of it would also be when the ICE is returning energy to the battery. Correct? Hope you can...er...um...clarify (!) that point for me. -Matt
Matt, Great question. I did run only in EV mode. You are correct to point out that if the car was in HV mode some of the negative power would have been generated by the engine recharging the battery and not just regen.
Of course! Thanks for the fast answer! Would you attack HV "recharge" data using the same AUC (area-under-the-curve) strategy, or analyze the data differently? -Matt
Well depends on what are you trying to answer. In the case of regen, the best thing is to run it in the EV mode and then look at the negative area under the curve as regen (since nothing else should be generating negative power). In the case of HV if you are wondering how much power is generated by the engine there is another parameter that is called "Instant engine power (based on fuel consumption)".That parameter is also in kW and I was able to see that when the engine is running at 1,500 RPM it is generating ~4kW of power and the HV/Battery power was showing -2kW at the same time. This means that the car was using 2kW and the other 2 kW produced by the engine was used to recharge the battery. The Car Scanner has the ability for you to create different dashboards and one of my dashboards has both the power by battery and power by the engine.
OK, so I have an update on the regen numbers. This time I recorder two trips in town. I drove somewhere and back (6.6mi each direction) and I have recorded the trip there and back. I got 40% regen in both directions. The numbers were so good that I started questioning my methodology but when I checked the area under curve against SOC number (SOC depletion * ~14kWh) everything matched. Anyways either my methodology is incorrect or in town regen is 40%! You decide.
