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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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Discussion Starter · #3 ·
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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Discussion Starter · #11 ·
Thx to all those who replied! My original post neglected to provide details about the comprehensive testing and research that I and the dealer service mgr did to try to figure this out. I was trying to keep it brief! And, yes, I drive in purely EV mode about 98% of the time and certainly during testing since the entire purpose was to test the battery range. Glad to see one of the replies reiterated the same experience both before and after a computer reset on the car. I haven’t tried to follow any steps to do the reset myself but what I have inferred is that it is not an easy thing to do and will prob require a trip back to my service mgr. There is a simple way to reboot the Tesla computer so I was hoping for the same type of solution for the Clarity. Thx again to all!!
 

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Thx to all those who replied! My original post neglected to provide details about the comprehensive testing and research that I and the dealer service mgr did to try to figure this out. I was trying to keep it brief! And, yes, I drive in purely EV mode about 98% of the time and certainly during testing since the entire purpose was to test the battery range. Glad to see one of the replies reiterated the same experience both before and after a computer reset on the car. I haven’t tried to follow any steps to do the reset myself but what I have inferred is that it is not an easy thing to do and will prob require a trip back to my service mgr. There is a simple way to reboot the Tesla computer so I was hoping for the same type of solution for the Clarity. Thx again to all!!
Sorry to be persistent but I couldn't tell from your post if any of the comprehensive testing involved using the odometer?

There was also an earlier question about this statement, "My battery has been checked and has the capacity for 50 miles of range when fully charged." Did they explain how they arrived at that figure? Because just like a full tank of gas will drive a car various distances depending on driving conditions, a full capacity EV battery will drive the car various distances depending on conditions.
 

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Discussion Starter · #13 ·
Sorry to be persistent but I couldn't tell from your post if any of the comprehensive testing

There was also an earlier question about this statement, "My battery has been checked and has the capacity for 50 miles of range when fully charged." Did they explain how they arrived at that figure? Because just like a full tank of gas will drive a car various distances depending on driving conditions, a full capacity EV battery will drive the car various distances depending on conditions.
Sorry to be persistent but I couldn't tell from your post if any of the comprehensive testing involved using the odometer?

There was also an earlier question about this statement, "My battery has been checked and has the capacity for 50 miles of range when fully charged." Did they explain how they arrived at that figure? Because just like a full tank of gas will drive a car various distances depending on driving conditions, a full capacity EV battery will drive the car various distances depending on conditions.
 

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Discussion Starter · #14 ·
Yes, the odometer was used in testing. I’ll try to explain using my Tesla which is pure EV. We bought it with lowest range and got about 200 miles between charges. Several years later we were given an upgrade to 250 range over the air - a software update. Now we drive farther between charges even though nothing physically changed in the car. The computer was told via the update to allow the battery to charge to a higher capacity - one that was always possible but was restricted by the computer in the car. Of course there were always minor variations in range due to habits and conditions but we reliably knew what to expect. The Clarity does the same thing - the computer is telling it to hold back on range because it is more economical. Only a computer reset will get the car to its full capacity - as I witnessed after the dealer’s reset. The majority of the time, a lower range is fine because I am driving less frequently. However, when I know I am going to be driving a longer distance, I would like to be able to charge to capacity and it seems the only way to do so is a reset.
 

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The range estimate does not equal battery capacity. It is just an estimate. It is a known fact Tesla sold the same exact battery for models with 200 mi range and 250 mi range, just limited the amount of available capacity (unless you initially paid extra for it). Then later decided to release the extra capacity out of consideration of COVID or some natural disaster relief. Most manufacturers do not do this. They have a certain amount of capacity they do not allow charging above to limit apparent (visible) battery degradation. If they limit to 80 %, as your battery goes from 100 % down to 98 %, down to 96 %, down to 94 %, etc, you see no change as they capped you at 80 % initially.

I do not know of an easy way to reset the meter. I do know there is a radio code so unlike in Prii unplugging the battery will make you have to unlock the radio. That would be my initial guess, unplug the 12 V. You can search the Honda service technical information at the independent workshop site here for a nominal fee. I have and found how to do my own maintenance:


Good luck...
 

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Yes, the odometer was used in testing. I’ll try to explain using my Tesla which is pure EV. We bought it with lowest range and got about 200 miles between charges. Several years later we were given an upgrade to 250 range over the air - a software update. Now we drive farther between charges even though nothing physically changed in the car. The computer was told via the update to allow the battery to charge to a higher capacity - one that was always possible but was restricted by the computer in the car. Of course there were always minor variations in range due to habits and conditions but we reliably knew what to expect. The Clarity does the same thing - the computer is telling it to hold back on range because it is more economical. Only a computer reset will get the car to its full capacity - as I witnessed after the dealer’s reset. The majority of the time, a lower range is fine because I am driving less frequently. However, when I know I am going to be driving a longer distance, I would like to be able to charge to capacity and it seems the only way to do so is a reset.
We have yet to see your odometer readings. The Guess-o-meter is just that, an estimate based on your recent driving history. What we need to determine if you have a problem with the car are actual road tests, including terrain, speeds, and temperatures.
 

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I do not know of an easy way to reset the meter. I do know there is a radio code so unlike in Prii unplugging the battery will make you have to unlock the radio. That would be my initial guess, unplug the 12 V.
This works on the Clarity also, the term often used is 12V reset. If you disconnect the negative battery terminal for a minute or so then reconnect it, this clears driving history, resulting in the EV range display (i.e. guess-o-meter) typically displaying somewhere in the 40's regardless of what it was displaying prior to the 12V reset. During summer when the guess-o-meter has been showing in the 50's, then after a 12V reset someone sees that it has suddenly dropped to something in the 40's, they think they have lost actual EV range. But they haven't, all that happened is that since 12V reset clears driving history, the guess-o-meter has no prior history to work with so it truly does have to guess at the EV range, so it just displays a default value. But after a few trips it starts to build up driving history again and it will usually settle back to where it was previously.

The reverse can happen in winter, if in cold weather the guess-o-meter has been showing say in the mid 30's, then after 12V reset the guess-o-meter is suddenly showing in the 40's, then it could lead someone to think that something has just magically increased their actual EV driving range. When all that actually happened is that the guess-o-meter was reset to default value, and again it will usually settle back to where it was previously after a few trips and it is able to build up some driving history.

12V reset also occurs whenever the 12V battery is replaced, as obviously the terminals have to be disconnected to remove the old battery. It also can occur if the 12V battery is completely drained down and the car is jump started.

As a side note regarding 12V reset, some people (well most people) become understandably alarmed when after starting the car for the first time after a 12V reset they see a bunch of very ominous warning messages about failed systems like ABS, TPMS, etc. But that is normal and just means that those systems need to reset themselves, which they do within the first mile or so of driving.
 

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The battery indicator on the left and the EV range are not in sync with each other. The power meter does not compare range data, driving habits, or sync with the EV Range directly. Full bars on the left = "fully charged" battery.

Where as the EV range is based on both driving habits and calculates those habits by the power % left on the battery.

Drain your battery to 2 bars, whether it's been 30 miles or 50 miles...it will still take 2 1/2 hours to "fully charge" with Level 2 regardless if it thinks it's giving you 30 or 50 miles back.



Now regards to "fully charge" -- if the battery indicator is fully charged on the left, it will stop charging the battery. Well...fully allowed... But again, charging is not based on EV range/habits or any history..it's just that the battery doesn't always Completely charge or fully drain when "dying" on your to save its lifespan on a macro level. (5-10++ years from now) -- But it gives you the same % of power every charge allowing more power over time as it degrades. But again, if you "drain your battery" it will always take the same amount of time to fully charge it again...regardless of how you drive, it's all about the power level available, regardless of how you used it.
 
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