Attention Prius Owners, I believe I have discovered a previously unknown Mechanism of Low MPG.

I will hopefully have my final video out by the end of this year. I have most of the content I need to make the actual video... I've just delayed making it because I'm distracted by other matters.

Yes this is a very real phenomenon. There is too much evidence in my own experience and other people's posts where they describe the exact same MAX and WEAK EV State Behavior between 2 Prius or Toyota Hybrids that can't be explained by anything else..

My guess is there's a process somewhat similar to Ignition Mapping that occurs for the Hybrid Battery. Ignition mapping is where the engine software tests different Ignition points to learn knock values (engine compression causes causes fuel mixture to preignite).

During prolonged highway driving where the Hybrid Battery can be maintained at roughly 60%... software in the HV ECU does an analysis of the Hybrid Battery based on capacity, resistance, Battery temperature and other factors using methods like columb counting.

Here is my original post describing increased EV Output after multiple commutes in a row (3rd highlight paragraph):



Here is a Gen 3 owner that experienced the same thing (3rd highlighted paragraph)



Both of us drove our vehicles on stop & go drive styles for hours a day due to our jobs. Me in action below:

I'm driving in the exact same spot in the exact same way multiple days in a row on the mail route. You become very sensitized to how the Hybrid System behaves at different States of Charges and the behavior of the Hybrid System delivering mail like this... which is why I'm the 1st person to connect the dots to all of these other posts and really done the leg work to filter out any other possible causes like stages of Hybrid Operation, Hybrid Battery Temp, etc.

Now compare two other posts from a 2020 Rav4 Hybrid and 2005 Gen 2 Prius.





They both describe the same phenomenon of one Hybrid putting out more EV Power than the other despite driving both in the exact same condition.

That's because one Prius/RAV4 has met the necessary condition to verify it's Hybrid System health via software measurements and allow aggressive usage of EV Output during city driving, and the other has not. Toyota has likely programmed some version of this software into all of their Hybrids... and thisactually led to a lawsuit against them in the 2015 timeframe...







The cause of the Low EV Output in this lawsuit was misattributed to a software update... where really the software update just activated the latent WEAK EV State Software due to resetting the HV ECU.

The plaintiffs were right that they were experiencing a loss of EV Power and mpg in city traffic because of the update... but it was an indirect result rather than direct which led to the lawsuit going knowhere as they were looking in the wrong place in the software for the issue. When they brought it to Toyota's attention, the cause was misplaced and Toyota was 100% correct in that the low EV Output/MPG was not caused by the Software Update.