Cash Traylor
Well-Known Member
There is a tremendous amount of good information here about HV and HV Charge mode and "best practices" and why would you use it etc. There is a lot of personal preference and operating habits. We all have our preferences. The one thing is that first, yes, the motors are brushless DC (asynchronous I believe but cannot find my notes now) which due to phasing of the DC current can be thought of as AC for this discussion. You have motor drivers (inverters) that phase the current to the motors to produce torque, then act as voltage and current controlled rectifiers (DC Chargers) to place the regen energy back into the battery during deceleration. The smaller motor/generator that is part of the ICE effectively is what is used for HV Charge mode as the ICE remains decoupled from the drive shaft (e-CVT) for most all of HV Charge operations. The choice of the 58% SOC for the HV Charge cut-off is likely very much what they said. It is the point where the ICE ceases to be efficient in operation as a generator relative to battery voltage. Honda made a big deal about their system managing efficiency. If you thought of HV Charge as a way to turn liquid fuel into electric fuel, and (no, it doesn't work like this but come with me on this journey) you turned on HV Charge and watched the fuel gauge go down while the electric gauge went up (net zero change in total range) - HV Range decrease but EV range increases. The cut off was selected when the generator was burning more gas than the car could convert into electric range. So if earlier (again I know) the "net total range" was remaining the same, you were just moving the miles from right to left on your dash, at about 58% the engineers noticed that the range was decreasing rapidly (of course they knew that from the specifications of the battery, gen, BMS, etc, but...) So that is why you don't charge further.
Now for my $0.00002 cents worth of "HV Charge button/mode" use input. Lithium chemistry batteries (even Li-PO4 to some extent) do not like being stored in a low state of charge (Hear me DEALERS!!! PLUG THE DANG CARS IN ON YOUR LOT ONCE IN A WHILE) for a long time. Now long is both objective and subjective, but for here lets say you drove your car to the airport to fly to a ship port for a 3 week cruise (I know, I am dreaming of vacation...) and would basically leave your car parked for almost a month at the charge you ended with, unable to charge it while away. It would be a good idea to use HV, or even HV Charge to put about 40-50% of the energy back in for storage chemical (separator plate) stability. Li-Ion cells like to be stored between 40%-60% SOC, not 100% and definitely not 20%. I used to fly a lot of Lithium powered RC aircraft using performance batteries (and you can check Battery University for info as well) and the rule of thumb was never discharge below 20% (which the Clarity protects automatically) nor store at 100% (again, mostly automatic). However, the Clarity will let you drive until the HV battery is at minimums and then switch to ICE, then you can continue to drive to your destination, park and leave it at "EV Empty" for as long as you want. However, that is not recommended - but not prevented by Honda. So again, if you are going to leave it parked for a while - plan your "end of trip" to include a half charged traction battery...
Cheers,
Cash
Now for my $0.00002 cents worth of "HV Charge button/mode" use input. Lithium chemistry batteries (even Li-PO4 to some extent) do not like being stored in a low state of charge (Hear me DEALERS!!! PLUG THE DANG CARS IN ON YOUR LOT ONCE IN A WHILE) for a long time. Now long is both objective and subjective, but for here lets say you drove your car to the airport to fly to a ship port for a 3 week cruise (I know, I am dreaming of vacation...) and would basically leave your car parked for almost a month at the charge you ended with, unable to charge it while away. It would be a good idea to use HV, or even HV Charge to put about 40-50% of the energy back in for storage chemical (separator plate) stability. Li-Ion cells like to be stored between 40%-60% SOC, not 100% and definitely not 20%. I used to fly a lot of Lithium powered RC aircraft using performance batteries (and you can check Battery University for info as well) and the rule of thumb was never discharge below 20% (which the Clarity protects automatically) nor store at 100% (again, mostly automatic). However, the Clarity will let you drive until the HV battery is at minimums and then switch to ICE, then you can continue to drive to your destination, park and leave it at "EV Empty" for as long as you want. However, that is not recommended - but not prevented by Honda. So again, if you are going to leave it parked for a while - plan your "end of trip" to include a half charged traction battery...
Cheers,
Cash