The reason I asked about your updates is that our Clarity has had the 18-089 (EVTC and 3-way Valve) and the 18-091 (HV mileage fix, current version of 18-069) software updates in early October. I think that the 18-089 update has changed how the engine and HV system operates. A couple of weeks ago, the engine started in our garage when I turned the heat on for freezing rain conditions. This was the first time the engine had started since the software update. I do not think this was a system check (no mention on display). The engine seemed louder to me but this could be subjective. After reading some comments in this forum about how the engine operated in HV mode, we took the Clarity out on a freeway drive to see if things had changed. We have driven the Clarity on the freeway for a hour or so every six weeks or so to exercise the engine as the Clarity is used entirely in EV mode normally. This last time, in HV mode the engine did not stay locked to the drive train all of the time when the speed was over 45mph. Instead, the engine disconnected when additional power was needed up hills of more than mild grade. The engine revved up to 3500+ rpm (rather than about 2500 rpm when locked in at 70mph - we had a tachometer display from a connected OBD2 dongle). Previously, the extra power needed was taken solely from the LiPo battery for the same grades and speeds. Also, on going down mild grades, the engine disconnected and shut off. Previously, the engine would stay locked in. Finally, the engine was more noticeable (a bit louder?), even when locked in than previously.Only update I have applied is the HV range one, Service Bulletin 18-069.
I have not had any of the other problems like warning lights or “chargus interruptus” (that one’s for @insightman) so I am hesitant to apply other updates and possibly upset the apple cart. Especially since my Clarity is working so great with no angry bees and plenty of power even at 2 bars. But I haven’t tried a public Charge Point EVSE. Mine works fine on a dual Aerovironment one though. If any problems do pop up, I’ll apply the updates but until then it’s steady as she goes matey.
Best car I’ve ever owned.
The above is not all for the worse. I think that the possible increase in noise, especially at startup idle (1500 rpm), may be caused by a change in the VTEC controlled valve timing to help with warmup and overall engine efficiency. The change in lock in behavior in HV mode at freeway speeds may be a change to help in the overall efficiency of the power train system. It seems, for our 100 mile trip (about 80 miles with the engine running), that the gasoline mileage increased as it appears we used less gasoline (by the gauge and the HV mileage change) than previously. This is something we can check the next time we add gasoline (later this month). Honda has stated that the VTEC valve timing can be changed for either efficiency or power operating modes. And, a gasoline engine, even an Atkinson-cycle one, works more efficiently at larger throttle openings and optimum rpm. So, perhaps Honda has found some better VTEC and drive-train settings to produce better highway mileage in the HV mode and to keep the LIPo battery at a constant state of charge. This comes at the slight expense of, perhaps, a bit quieter HV operation at freeway speeds with a slight "angry bees" sound when a moderate amount of extra power is needed. I think that on balance, the software updates are good, especially for those that had the "multiple system warnings" (as we did).
As Kentucky Ken has said, the Clarity is one of the best cars I have driven and this is so even after the software updates. We are very happy with our Clarity.
LeoP