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Discussion Starter · #1 ·
Through trial and error and research, I discovered that the AI on the Clarity (2018) will reduce the “full” status of the battery when charging. In other words, the capacity may be 50 but it thinks the battery is fully charged when it reaches 36-38. This happened during Covid when driving far fewer miles, charging less frequently, not driving on freeway at higher speeds, etc. the AI “decided” I didn’t need to charge to capacity. The dealer didn’t understand this until I finally proved it through a full reset of the computer. The range is down again and I’m wondering if anyone knows how I can do the computer reset without going to a dealer. We are going on a road trip and I want it to charge to the real full capacity. Thanks!
 

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Through trial and error and research, I discovered that the AI on the Clarity (2018) will reduce the “full” status of the battery when charging. In other words, the capacity may be 50 but it thinks the battery is fully charged when it reaches 36-38. ...
Welcome to the forum.

It sounds like you are talking about the "EV Range" indicator. 36-38 miles is about what I see for non-highway driving. This range estimate is derived from current battery charge level and recent power consumption (2018 Clarity Manual P.129). Its ability to predict future driving range is, um, imperfect; many owners call it the "Guess-O-Meter". Factors such as a change in temperature or a change in driving style -- such as a long trip -- will affect the estimate over time. To my knowledge there is no easy way to reset or adjust it.

The EV Range estimate does not influence charging. When the curved white battery gauge at the left of the instrument panel reaches the top (20 bars), then the battery is fully charged. If charging stops before that, then something else is going on. Perhaps the Clarity's charging schedule has been enabled, or Honda SmartCharge.

Range estimates are a topic of frequent discussion here. You can find more information by searching for headings such as "EV Range" or "Battery Range".
 

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Let me try to describe the issue I am referring to again. When every dashboard indicator says that my car is fully charged - this is not actually true from a capacity standpoint. My battery has been checked and has the capacity for 50 miles of range when fully charged. However, the car’s computer has told the system to indicate fully charged at 38 “miles” of range based on driving and charging habits. It thinks that it is more economical and, in truth, it does usually meet my current (wfh) daily driving needs. However, when I need a greater range and want to charge to the fullest capacity of the battery, I need to somehow trick the computer into allowing me to do so. I was able to do this once before via the dealer with a computer reset. My question to the forum is to find out if it is possible for me to trigger the reset on an as-needed basis. I do understand the other range issues discussed on the forum and have read the prior threads but did not find anything related to my question. Prior to Covid, I had no idea that this type of issue was real and neither did the dealer. We went through a comprehensive process and demonstrated evidence that what I am describing is a real issue with the computer. It isn’t about weather or temp, etc. This issue occurs when the car switches from daily driving and charging to driving only rarely for short distances at slower speeds with infrequent charging (maybe once a week). To repeat, it indicates fully charged but is in fact only partially charged due to the artificial intelligence (AI) of the computer determining that this is the most economical range based on daily driving needs.
 

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The 2018 Clarity Owner's Manual p.331 describes how to do a Factory Data Reset, but does not say whether that affects anything beyond the infotainment system. Certainly you would have to redo all your custom settings afterwards (phone numbers, apps, locking and lighting options, etc.).

Mileage Computer did not update suggests disconnecting the 12v battery for at least two hours.

Are you using an OBD-II sensor to measure the battery capacity, or some other method?

You could try posting this question in the Honda Clarity Tech Section, to reach a more technical audience.
 

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Let me try to describe the issue I am referring to again. When every dashboard indicator says that my car is fully charged - this is not actually true from a capacity standpoint. My battery has been checked and has the capacity for 50 miles of range when fully charged. However, the car’s computer has told the system to indicate fully charged at 38 “miles” of range based on driving and charging habits. It thinks that it is more economical and, in truth, it does usually meet my current (wfh) daily driving needs. However, when I need a greater range and want to charge to the fullest capacity of the battery, I need to somehow trick the computer into allowing me to do so. I was able to do this once before via the dealer with a computer reset. My question to the forum is to find out if it is possible for me to trigger the reset on an as-needed basis. I do understand the other range issues discussed on the forum and have read the prior threads but did not find anything related to my question. Prior to Covid, I had no idea that this type of issue was real and neither did the dealer. We went through a comprehensive process and demonstrated evidence that what I am describing is a real issue with the computer. It isn’t about weather or temp, etc. This issue occurs when the car switches from daily driving and charging to driving only rarely for short distances at slower speeds with infrequent charging (maybe once a week). To repeat, it indicates fully charged but is in fact only partially charged due to the artificial intelligence (AI) of the computer determining that this is the most economical range based on daily driving needs.
The only way to measure the actual EV range of the car is to note the odometer reading when the car has been charged, and then the odometer reading when the car runs out of charge and the engine starts up. This test requires that you do not switch to HV during this time, so that the miles driven reflect the actual number of miles driven fully electric. Using the trip meter can help make this test easier.

The only way that you would know if you have lost actual EV range is if you have done the above test several times per year during your ownership of the car and seen the actual range go down over time, comparing tests conducted at the same time of year and in similar driving conditions.

As indicated in the first reply that you received, the range that is displayed on the dash is just an estimate it is not the actual electric range of the car, and in fact can at times be completely inaccurate. Fluctuations in the estimated range displayed on the dash do not necessarily reflect changes in actual EV range.

Maybe you know all of this already, but if so you did not state it so that is why people are asking you questions, because in order to provide helpful advice we need to know exactly what you looking at.
 

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... My battery has been checked and has the capacity for 50 miles of range when fully charged. ...
In re-reading your description, this sentence is what I find most confusing. Can you describe what measurements were done, and what calculations were made? Battery capacity is normally measured in amp-hours. Converting that to miles requires some assumption for how many miles you get per amp-hour. Also, was the calculation based on the battery's full rated capacity, or on a somewhat lower nominal capacity that manufacturers usually specify in order to reduce battery degradation? "Fully charged" normally gets you this lower capacity, so estimates based on full rated capacity are less realistic.
 

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Sounds exactly what I went through in Nov 2020 w/ my 2018 Clarity. Three session w/ Honda technicians (who frankly know zero about the Clarity), ultimately pulled in a Honda Engineering Rep and finally they were able to convince my engineering brain that system is working as designed. They used the Honda Diagnostic System (Ver 1.006.013) to confirm my battery capacity supported 55.0Ah (full capacity) and all my other battery indicators were good (look under Vehicle Selection>System Selection Menu>Electric Powertrain>Data List in the Honda Diagnostic System tool). Yet, all indicators on the dash only equated to 32-33 miles of EV Range. I argued forcefully that either my battery was deficient or was not charging to capacity. They finally convinced me they were correct by disconnecting my battery for probably 30 minutes and then reconnecting it which reset the "AI" removing all my admittedly bad driving history. EV Range guess-o-meter immediately jumped back to 50+ miles...and proceeded to degrade over the next few weeks back to 32-33 as I proceeded to drive too fast :-(. On the bright side, it gets back up into the low 40 range during the summer, then back in mid-upper 30s when weather cools down. Bottom line, that Ah (Ampere Hour) conversion to EV mile range guess-o-meter on the dash is totally dependent on your driving habits & affected by outside temps. What really matters is how many miles you are actually able to get on a charge. Sadly, with my driving habits the guess-o-meter isn't far off. For primarily highway miles at 80-85mph, I'm lucky to get 30-35 miles on strictly EV. It was also true right after the reset when my guess-o-meter erroneously told me I had 50+ mile range.
 

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... They finally convinced me they were correct by disconnecting my battery for probably 30 minutes and then reconnecting it which reset the "AI" removing all my admittedly bad driving history. EV Range guess-o-meter immediately jumped back to 50+ miles...and proceeded to degrade over the next few weeks back to 32-33 as I proceeded to drive too fast ...
It sounds to me like 50 miles is just a default initial value, which turns out to be optimistic for most situations.
 

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OP needs to clarify whether he/she actually got those miles driven in pure EV mode until engine kicked in. If it’s the guess-o-meter then forget it. According to Hondas publication, although the Figure is not clear, the optimal speed for max range (50+mi) is 18-40 mph, and it peaks at 28mph (55mi). If you drive 60mph you get 39mi range. At 80mph 28mi range.

Temperature also plays a big role. From experience, anything below 60F outdoor then miles drop.

Other quirks on a mild summer day at 70F, if you turn on AC set to 68F, the heater will also run using electricity just to blend with the AC cold air. For ICE cars heat is a waste byproduct and free so it doesn’t matter. AC uses much less power than the resistive electric heater.

On another note I’m guessing the actual battery capacity reported through ODB adapter updates only after draining to 10% (until engine kicks in) followed by a full charge. I’ve been charging discharging between 20-80% and the reported capacity was not changing for several months. It finally dropped a little after doing drain and full charge, but it may be a coincidence.
 
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