RPM data part deux

Discussion in 'Clarity' started by Clarity_Newbie, Mar 14, 2019.

  1. Clarity_Newbie

    Clarity_Newbie Active Member

    Data collected Feb 1 - Feb 28th

    17 drive days, 751 miles, ~26 hours of driving. 64 log files generated 258,424 data points. GVW 4260. Temps 25F to 58F...several days of rain, couple days of wind.

    For perspective...I live in the mountains and run the valley floors which are flat to rolling. Otherwise varying degrees of steepness prevails. For example...I lose ~2 miles EV like clockwork when I drive the last 1/2 mile to the house at ~25 mph.

    I operated the Clarity as I would normally do...no special roads or testing conditions. Unlike the first RPM data test which was conducted solely in HV mode, this go-a-round the Clarity was in EV mode 77.8% of the time with the remaining in HV mode. Neither Sport mode nor ECON mode was utilized.

    Clarity charged as needed to maintain SoC to ensure adequate EV range available for the next days drive. Typically I charge to 75% - 95% by using 9 hours charge time instead of charge to full.

    As I normally do every month, I purposely ran the Clarity in HV mode two days for the entire day. On HV mode days...SoC always 80% or higher.

    As a matter of course, when I decide to run the cabin heat...I put Clarity in HV mode.

    Both HV mode only days and heat-on events can be spotted on the chart depicting the entire 17 day run. Skinny spikes on chart indicate cabin heat-on events.

    Typically I will put heat on, when temps ~ 45F or less...otherwise seat heating does the job...especially when the sun is out.

    I used the same breakpoints for February data as January data for ease of comparison. Link to January data for those interested: https://insideevsforum.com/community/index.php?threads/hv-only-gas-mileage.4089/page-3#post-45189

    January results in black. February results in red.

    Clarity Speed breakdown
    • 1 - 35 mph..........39.4%...........40.3%
    • 36 - 60 mph........42.3%...........47.5%
    • 61 - 79 mph........18.3%...........12.2%

    Clarity RPM breakdown
    • 1 - 1000..............40.47%.........78.2%
    • 1001 - 2600........56.59%.........20.1%
    • 2601 - 3600..........2.39%...........1.6%
    • 3601 - and up.......0.55%..........0.08%

    Clarity February data with 0 RPM’s removed
    • 1 - 1000...................1.9%
    • 1001 - 2600............90.7%
    • 2601 - 3600..............6.8%
    • 3600 - and up...........0.5%

    Based on 21 drive days (Jan/Feb combined) for data collection (~340,000 combined data points)...the conclusion for the Clarity I drive is I can expect 1000 to 2600 RPM’s while in HV mode with rare spikes above 3000 RPM’s. Weather and/or terrain and/or speed are the obvious culprits for RPM’s above 2600. The chart demonstrates this very nicely.

    Hope this helps with those who are trying to gauge RPM’s for their own Clarity. I have empathy for those who express concerns over “angry bees” and/or loss of power accompanied by high revs according to some owners.

    Some forum posters say RPM’s haven’t breached 2000...others say 3000 plus is routine. I’d love to see more data so we as a collective whole can perhaps narrow down what is “normal” expectations for the Clarity.

    As everyone knows but is still worth repeating...individual driving habits are a huge variable in how this car will operate.

    As a side note...HV mode engine clutch engagement remains predictable and consistent. Clutch engagement occurs at speeds of 45 to 70 mph.

    pdf attached with some comments and two charts depicting 17 day run...RPM's over MPH.

    ***These charts/data is not being presented for reverse engineering. The sole purpose is to demonstrate one Clarity’s RPM range with associated speed to folks who believe the Clarity they drive has RPM issues. At least it is a start and some comparisons can be drawn if owners collect OBDll data.

    Good luck!

    Attached Files:

  2. sniwallof

    sniwallof Active Member

    Very useful study and data, nicely done! Remind us which OBDII hardware/software you are using.

    Except for reverse engineering for the express purposes of defeating some sort of software protection (e.g. (digital rights management) DRM), I do not think there is any prohibition (or worry) for any reverse engineering in the conventional sense.
    Kailani and KentuckyKen like this.
  3. The Gadgeteer

    The Gadgeteer Active Member

    CN, thank you so much for collecting this data. This is great.

    It seems that your Clarity spends most of the either with the engine off or in a normal economical rpm range which I suppose it what is supposed to happen.

    Do you use HV mode on cold days on the premise that engine heat will be leveraged and thus offsetting using battery power to generate it for cabin climate control? I know below a certain temperature (20F?) the engine will start to help with heat and other things. I have been wondering if it leverages engine heat above that temperature if the cabin climate control asks for heat if the engine is still hot from running for other reasons like running more often due to HV or HV Charge.
  4. Sandroad

    Sandroad Well-Known Member

    Awesome! Thanks for the charts and explanation of your driving. If I were to make a WAG, I'd say all Claritys would operate the same with the same driver and same conditions. There is no reason for the software/hardware to be different in individual cars.
  5. Clarity_Newbie

    Clarity_Newbie Active Member


    I use the Kiwi 4 by PLX devices. Here is a link to more info from a previous post.


    Hope this helps.
  6. Clarity_Newbie

    Clarity_Newbie Active Member


    The chart is compressed time as it covers ~26 hours of drive time. If I were to post a chart of one of the "skinny blue spikes"...one would see more variance in RPM's and use of EV mode since the car goes back n forth between ICE and EV mode depending on speed/stopping/throttle position etc. 30 minute drive time is a close average for each "skinny blue spike".

    I run HV mode when I run the heat simply because it is much less detrimental to the SoC/EV range. For my driving patterns, I see no sense in running heat while in EV mode since it will deplete the SoC noticeably quicker. Since 50 miles a day is average for me...I'd be on HV mode any way at some point most likely. It works well for me since I typically run heat only in the morning then let solar do its job...plus the seat heaters..then the rest of the day is almost a guarantee to be "all EV".

    Hope this helps.
    Last edited: Mar 16, 2019
  7. Clarity_Newbie

    Clarity_Newbie Active Member


    Agreed. Folks need to compare apples to apples...a sedate driver who rarely "floors" the pedal or who does the speed limit or who doesn't see how quick they get "from 0 to 60 mph'...will most likely have data similar to mine.

    Conversely, if someone does 80 mph or zips in and out of traffic or is constantly in up-tempo driving mode...will most likely see much different results. No right or wrong...just different styles.

    That's why I posted the "sedate driver" data so folks have at least one Clarity to compare data against...but who is to say the Clarity I drive is "normal"...dunno. That's what I am trying to find out...set a baseline.
  8. Walt R

    Walt R Active Member

    I've wondered the same thing. The following is pure speculation, but this is what I expect:

    The Clarity electric heat is described as directly heating the core, from where heat is transferred to air blowing into the cabin. Thus, I assume that the electric heat control measures the temperature in the core directly to determine whether to supplement it. Thus, if the core were warm from the engine previously running, I would not expect the electric heat to come on even though the engine is no longer running.

    The interesting question to me is whether the reverse is true. When put in HV from a cold start, will the electric heat still come on to heat the core before the engine does, using battery charge to do so? Or is there logic that says "engine is on, don't heat the core even though it is still cold"? I've noticed that the Clarity starts putting warm heat into the cabin much more quickly than my Prius did, about 2 minutes vs. 5. But I haven't run HV from the start often enough to notice if the time to heat is different when on HV and cold.
  9. sniwallof

    sniwallof Active Member

    I ordered one. Not sure why it's $99 on Amazon, and $149 on sale at the PLX website, but Amazon claims its the same one with the SD card. I never buy warranties for stuff like this, but someone said their's failed at 6 months, so I added the 4 year Amazon warranty for $6, possibly a waste, oh well. None remaining tonight, I think you sold a few of them.


    Apology if you posted this before, which parameters are you recording on the SD card. Is it six max? Sounds like at least two are engine RPM and vehicle speed.
    Last edited: Mar 16, 2019
  10. The Gadgeteer

    The Gadgeteer Active Member

    I read a technical document somewhere on the Clarity and let me tell you this is a complex car. Anyway, one item I recall was there are some valves that isolate the heater core from the engine coolant for when the electric heat is heating. The same article also said the engine will help with heat below a certain temp and those valves will open. I think that temp was 15F or 20F. I will have to look for the document. I also read that if the engine coolant temp rises with the engine off then an error is generated because the heater core valve(s) must be stuck open causing the electric heater to loose heat to the engine.
  11. The Gadgeteer

    The Gadgeteer Active Member

  12. Clarity_Newbie

    Clarity_Newbie Active Member


    Looks like the same one to me.

    Any electronic device regardless of manufacture/how much it costs...X% will have issues. This is a new device without much history...much like the Clarity. I have an issue with the 32 gb SD card I am using and working with PLX engineering on it to help the cause. Otherwise, the device has worked flawlessly in self-run mode for ~9 weeks of data collection or roughly ~2000 miles.

    Most of the negative reviews are for the Kiwi app and connecting with bluetooth. I use the Kiwi app to A) set-up vehicle, B) choose parameters to log while collecting data and C) to place device into self run mode. The app has not been an issue for me nor has been connecting to bluetooth. The app is not intuitive per se but if you can cipher on the go...its not hard to figure out. When I ran the device twice in manual mode, I used Torque Pro app...once on a Toyota and once on a Subaru...works like it is supposed that way as well.

    The PLX Kiwi4 is capable of recording up to 16 parameters according to the documentation. I have run data collection for 12 parameters with no issues. IMHO the relative high cost is due to the capabilities to receive/transmit data at not only a high rate...but also volume (ie) up to 16 parameters...plus the ability to "set and forget it" with SD card feature. These are the factors that are important to my group. I have placed the device on a friends Clarity and she drove it for a few weeks and didn't even know it was there. Same for the Toyota.

    I put the device on the Clarity February 1 and didn't remove till February 28th...so real convenient. You can choose multiple log file configurations which are generated as .csv files. I chose to create a new log file every time the Clarity is started. That way I could easily isolate a particular run if needed. To each his/her own.

    The core data I collect is:
    Air temp
    Engine load
    Manifold air pressure
    Speed (mph)
    CO2 emissions
    12v battery
    Engine HP
    Engine torque
    Throttle position...

    ...and played around with a few others. The one thing it does not collect right out of the box is state of charge (SoC) for the traction/hybrid battery. I am not sure if it is a function of the device or the capabilities of the kiwi app...I really should test the Clarity with Torque Pro to see if it registers SoC through the PLX device to be sure. I don't have much incentive since the Clarity I drive acts the same whether SoC is 80% or 20%.

    At the end of the day...if all one wants to do is some short term testing to get a handle on how their car is performing..then a $30 device does great. All half-decent OBDll scanners will do a fine job collecting the core information and sending to phone app for review. If long-term testing on multiple vehicles is a need...or you just don't want to mess with electronics every time you get in the car...then the PLX is an alternative. Again...each his/her own. No right or wrong.

    Sorry for the long post but figured folks who read this will have most questions answered about the device.

    Hope this helps.

    Good luck
    Last edited: Mar 17, 2019
    sniwallof likes this.

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