Another theory for HV-charge vs HV

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I’m having the same experience as @David Towle. Except for when in regen, hard acceleration, and steep hills when it obviously has to be off, I can’t see any rhyme or reason when it decides to be in or out of gear mode. Some trips it’s a lot and some not much even with speed and terrain similar.
 
KentuckyKen said:
I’m having the same experience as @David Towle. Except for when in regen, hard acceleration, and steep hills when it obviously has to be off, I can’t see any rhyme or reason when it decides to be in or out of gear mode. Some trips it’s a lot and some not much even with speed and terrain similar.
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If the state of charge runs down too far from the setpoint when you activated HV the gear mode disengages. It’s likely to happen on any hill with more than 3- 400 feet of elevation change. At higher speeds, especially above 80 you’re likely to lose state of charge faster than gear mode can keep up. Also when it’s cold and windy it wont always stay in gear mode.
If I want to stay in gear mode I’ll cycle out of HV and back within a few seconds in the middle of the hill climb. The engine stays running and gear mode reengages immediately.


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HagerHedgie said:
If the state of charge runs down too far from the setpoint when you activated HV the gear mode disengages. It’s likely to happen on any hill with more than 3- 400 feet of elevation change. At higher speeds, especially above 80 you’re likely to lose state of charge faster than gear mode can keep up. Also when it’s cold and windy it wont always stay in gear mode.
If I want to stay in gear mode I’ll cycle out of HV and back within a few seconds in the middle of the hill climb. The engine stays running and gear mode reengages immediately.
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Click to expand...

I'm usually above 40% charge and almost never above 72 mph.

If I switch out of and back into HV it runs in EV for a mile or 2 burning up a couple bars before it goes back into gear mode. So its not worth it.
 
KentuckyKen said:
I’m having the same experience as @David Towle. Except for when in regen, hard acceleration, and steep hills when it obviously has to be off, I can’t see any rhyme or reason when it decides to be in or out of gear mode. Some trips it’s a lot and some not much even with speed and terrain similar.
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KentuckyKen

Just a rehash of data collection efforts for those who are new'ish forum members. Thought it might add to the conversation.

From a post made back in March 2019...

..."Engine clutch mechanism engages as I expect on all roads where speed limit is ~45 or greater. When maintaining 45 mph speed or greater...it goes off when climbing noticeable grade and when descending a similar grade. Otherwise...stays on majority of the time when maintaining speed. Very pleased with performance of the engine clutch"...

The data collected to date points to a certain RPM range where the clutch will engage/disengage at a given speed. As posted several times...as an example...clutch engagement in the Clarity I drive comes on like clock work at 45 mph/~1625 RPM when desired speed is reached and I maintain that speed and RPM. When I say like clock work...I mean in the literal sense.

The data also demonstrates when I am at speed (ie) 45 mph...if the RPM is greater than/less than 3% of the threshold (ie) ~1625...then the gear icon will either disengage or not engage.

Every time I notice the the clutch disengage...RPM's have increased or decreased past the 3% threshold whilst maintaining speed. Uphill more power thus higher RPM's...downhill less power even goes into EV mode.

The data collected also indicates a strong correlation of RPM/clutch engagement at 5 mph increments up to 65 mph. (ie) 50 mph clutch engagement at ~1800 rpm for example. Very predicable at given speed and RPM. Same 3% threshold applies to all speeds = 3% higher/lower RPMs = clutch disengagement or won't engage.

I don't have the opportunity to drive on flat ground often so my experiences are rolling to mountainous roads. I have no real idea how the Clarity operates in south Florida or West Texas on pseudo flat ground.

At the end of the day..the clutch engagement remains predicable based on speed/RPM thresholds for the Clarity. The question is why does the Clarity increase/decrease RPM's for no apparent reason when maintaining speed on the same stretch of road? Under similar conditions? Generator? Needs mo power? Dunno.

Scan Gauge II works great for the correlations. The Autel Maxi AP200 provides interesting data as it includes three RPM levels...Engine RPM...Motor RPM...Generator RPM. Still trying to cipher the what and the why on the differences...may be nothing. Interesting thing is when the Clarity is on the move...each of the above display significantly different RPM numbers.

It would be great if mo folks would collect mo RPM data so we can collectively hone in on this issue.

Hope this helps.
 
Clarity_Newbie said:
The question is why does the Clarity increase/decrease RPM's for no apparent reason when maintaining speed on the same stretch of road? Under similar conditions? Generator? Needs mo power?
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I’d hazard a guess that the generator is providing variable amounts of power to the motor and batteries as deemed necessary by the engineers.
 
Clarity_Newbie said:
KentuckyKen

Just a rehash of data collection efforts for those who are new'ish forum members. Thought it might add to the conversation.

From a post made back in March 2019...

..."Engine clutch mechanism engages as I expect on all roads where speed limit is ~45 or greater. When maintaining 45 mph speed or greater...it goes off when climbing noticeable grade and when descending a similar grade. Otherwise...stays on majority of the time when maintaining speed. Very pleased with performance of the engine clutch"...

The data collected to date points to a certain RPM range where the clutch will engage/disengage at a given speed. As posted several times...as an example...clutch engagement in the Clarity I drive comes on like clock work at 45 mph/~1625 RPM when desired speed is reached and I maintain that speed and RPM. When I say like clock work...I mean in the literal sense.

The data also demonstrates when I am at speed (ie) 45 mph...if the RPM is greater than/less than 3% of the threshold (ie) ~1625...then the gear icon will either disengage or not engage.

Every time I notice the the clutch disengage...RPM's have increased or decreased past the 3% threshold whilst maintaining speed. Uphill more power thus higher RPM's...downhill less power even goes into EV mode.

The data collected also indicates a strong correlation of RPM/clutch engagement at 5 mph increments up to 65 mph. (ie) 50 mph clutch engagement at ~1800 rpm for example. Very predicable at given speed and RPM. Same 3% threshold applies to all speeds = 3% higher/lower RPMs = clutch disengagement or won't engage.

I don't have the opportunity to drive on flat ground often so my experiences are rolling to mountainous roads. I have no real idea how the Clarity operates in south Florida or West Texas on pseudo flat ground.

At the end of the day..the clutch engagement remains predicable based on speed/RPM thresholds for the Clarity. The question is why does the Clarity increase/decrease RPM's for no apparent reason when maintaining speed on the same stretch of road? Under similar conditions? Generator? Needs mo power? Dunno.

Scan Gauge II works great for the correlations. The Autel Maxi AP200 provides interesting data as it includes three RPM levels...Engine RPM...Motor RPM...Generator RPM. Still trying to cipher the what and the why on the differences...may be nothing. Interesting thing is when the Clarity is on the move...each of the above display significantly different RPM numbers.

It would be great if mo folks would collect mo RPM data so we can collectively hone in on this issue.

Hope this helps.
Click to expand...

Pay attention to the state of charge of the battery when you notice that behavior from the engine. I only really notice it at a high state of charge after aggressive driving; the car wants to re-charge the battery but it keeps limiting the charge rate.


Sent from my iPhone using Inside EVs
 
Landshark said:
The wife and I thought the car looked like a Landshark, especially in Solar Silver. I was pleased to find that the name was available.

Some may be too young to remember the Landshark from SNL.
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Wow. Parallel universe. I remember the Landshark and have the same silver Clarity.
 
MrFixit said:
I like this thought... I have found that HV mode does 'maintain' charge level (some have reported a steady loss of charge). But - it seems impossible to maintain charge during a long HV trip because of 2 things... First, whenever you stop and re-start, it establishes a new charge 'setpoint' which is invariably a little lower than what you had previously. Also, I think everyone (in spite of good intentions, and post-it notes) forgets to engage the darned thing every time!. On a 'long' trip with a lot of stops and starts, it becomes virtually impossible to maintain charge level.

This seems like a good use of HV charge mode - to provide 'makeup' charge for losses due to human error (failure to re-engage) or setpoint losses due to re-engagements.
Click to expand...

A few weeks ago we took a 3,000 mile trip over 12 days and used HV for virtually all those miles. I found the SOC did not fluctuate greatly while in HV and seemed to maintain at least 90% of the charge level at the start of a day's drive. I did not record the actual numbers nor study it scientifically, so this is purely anecdotal.
 
I have a long trip planned in a few weeks, so I’ll monitor the battery level and EV range while driving in HV. On the last long trip, 2 months ago, I recall the battery level remaining at or near 50%, up and over the grapevine on I-5.

Is it possible that programming on the 2019 differs from 2018? Ours was built 5/19.
 
Clarity_Newbie said:
KentuckyKen

Just a rehash of data collection efforts for those who are new'ish forum members. Thought it might add to the conversation.

From a post made back in March 2019...

..."Engine clutch mechanism engages as I expect on all roads where speed limit is ~45 or greater. When maintaining 45 mph speed or greater...it goes off when climbing noticeable grade and when descending a similar grade. Otherwise...stays on majority of the time when maintaining speed. Very pleased with performance of the engine clutch"...

The data collected to date points to a certain RPM range where the clutch will engage/disengage at a given speed. As posted several times...as an example...clutch engagement in the Clarity I drive comes on like clock work at 45 mph/~1625 RPM when desired speed is reached and I maintain that speed and RPM. When I say like clock work...I mean in the literal sense.

The data also demonstrates when I am at speed (ie) 45 mph...if the RPM is greater than/less than 3% of the threshold (ie) ~1625...then the gear icon will either disengage or not engage.

Every time I notice the the clutch disengage...RPM's have increased or decreased past the 3% threshold whilst maintaining speed. Uphill more power thus higher RPM's...downhill less power even goes into EV mode.

The data collected also indicates a strong correlation of RPM/clutch engagement at 5 mph increments up to 65 mph. (ie) 50 mph clutch engagement at ~1800 rpm for example. Very predicable at given speed and RPM. Same 3% threshold applies to all speeds = 3% higher/lower RPMs = clutch disengagement or won't engage.

I don't have the opportunity to drive on flat ground often so my experiences are rolling to mountainous roads. I have no real idea how the Clarity operates in south Florida or West Texas on pseudo flat ground.

At the end of the day..the clutch engagement remains predicable based on speed/RPM thresholds for the Clarity. The question is why does the Clarity increase/decrease RPM's for no apparent reason when maintaining speed on the same stretch of road? Under similar conditions? Generator? Needs mo power? Dunno.

Scan Gauge II works great for the correlations. The Autel Maxi AP200 provides interesting data as it includes three RPM levels...Engine RPM...Motor RPM...Generator RPM. Still trying to cipher the what and the why on the differences...may be nothing. Interesting thing is when the Clarity is on the move...each of the above display significantly different RPM numbers.

It would be great if mo folks would collect mo RPM data so we can collectively hone in on this issue.

Hope this helps.
Click to expand...
This makes no sense that engagement is predictable based on speed/rpm thresholds unless you're only considering summer perfect weather data. How can I drive for hours in the winter between 65 and 70 mph on rolling highways and the gear mode never engages? There are clearly other factors besides the speed/rpm thresholds that control engagement of gear mode, I think both precipitation (humidity?) and temperature are factors..
 
IMHO, the RPM data is a symptom of gear mode, and not the cause. Gear mode is determined by the SOC.

In HV mode, the ICE will not start until the SOC drops. After the ICE starts, the SOC will continue to drop while the ICE comes up to temperature. If the SOC drops too much during ICE warmup, it will be tough to get back to SOC and engage gear mode.

The HV reset can jump the gear mode setpoint, and get the car back into gear mode.
 
I'd be happy to receive suggested lottery numbers from anybody who can accurately predict the operation of "gear mode."
 
David Towle said:
This makes no sense that engagement is predictable based on speed/rpm thresholds unless you're only considering summer perfect weather data. How can I drive for hours in the winter between 65 and 70 mph on rolling highways and the gear mode never engages? There are clearly other factors besides the speed/rpm thresholds that control engagement of gear mode, I think both precipitation (humidity?) and temperature are factors..
Click to expand...

I’m pretty sure it only has to do with the SOC. Your driving style, speed, and the terrain all effect energy consumption. If gear mode can’t keep up with the power you’re asking for, then you won’t see it engage very often. I keep a close eye on the little gauge in the middle of the dash the tells you your HV and EV miles remaining to within a 10th of a mile.
If I’m going up a long hill or it’s very cold and windy, or if I feel like driving over 75 miles an hour for an extended period of time, I will cycle in and out of HV mode to maintain gear mode. I cycle in and out in just two or three seconds and the engine doesn’t even turn off.
It took me about six months of driving and 15,000 miles For me to figure it all out. At this point I could tell you exactly when gear mode is going to engage and disengage. I pay very very close attention to the state of charge compared to when I engaged HV mode.
You can go about 3 to 4 miles of EV range below the setpoint before the car kicks out of gear mode.
Don’t be afraid to cycle in and out of HV mode. the car is not that smart it can’t see the hill up in front of you. I think the engineers knew this.


Sent from my iPhone using Inside EVs
 
insightman said:
I'd be happy to receive suggested lottery numbers from anybody who can accurately predict the operation of "gear mode."
Click to expand...
I don’t play the lottery or go to casinos because I hate to lose. But I’ll bet you any amount of money I can tell you exactly when the gear mode is going to engage and disengage.
Pay close attention to the state of charge to within a 10th of a mile. When you’re more than three or 4 miles away from when you hit the HV button you won’t see gear mode a whole lot.
The two biggest things you could do see gear mode more often are slow down and cycle thru HV mode as soon as the gear disengages.
It’s really hard to keep the gear engaged if you’re going over hills with more than 200 feet of elevation change and/or driving over 75. Use the button! It saves gas


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HagerHedgie said:
I only really notice it at a high state of charge after aggressive driving; the car wants to re-charge the battery but it keeps limiting the charge rate.
Click to expand...

How have you been able to determine the “charge rate” of either the ICE generator or regenerative braking?
 
Landshark said:
How have you been able to determine the “charge rate” of either the ICE generator or regenerative braking?
Click to expand...

Just a quick and dirty estimate. When braking I would guess it’s maxing out somewhere between 30-50kw if the battery is warm and SOC is under 80%.
I know it’s limited when cold and at high SOC. I know the motor puts out about 120kw and the battery maxes out around 80kw so probably around 40kw for generator.
A couple times at very low SOC I have seen the generator add 5 miles in a minute or two after aggressively climbing a hill. It was high revs and I was basically gliding. So that corresponds with about 40kw.
These are just estimates. I like to think about this stuff when I’m driving. I keeps my brain busy.


Sent from my iPhone using Inside EVs
 
Charge rates are expressed as a decimal fraction of a batteries capacity. For Lithium, typical charge rates are .5C-1.0C with .8C being a common target.

We would need to know the voltage and amperage being supplied by the generator or regenerative braking in order to determine the C-rate.

I would imagine that the charge rate from regenerative braking/chevrons and the generator would be infinitely variable depending on SOC, braking force and throttle position.
 
Landshark said:
Charge rates are expressed as a decimal fraction of a batteries capacity. For Lithium, typical charge rates are .5C-1.0C with .8C being a common target.

We would need to know the voltage and amperage being supplied by the generator or regenerative braking in order to determine the C-rate.

I would imagine that the charge rate from regenerative braking/chevrons and the generator would be infinitely variable depending on SOC, braking force and throttle position.
Click to expand...

I would agree. I’m just going by feel and what I’ve experienced. I would imagine Hondas first priority was preserving battery life. When I first got the car winter was just setting in here in MD. It’s not very cold but we have our share of days in the 20’s and see teens and even single digits a few times a year. I was frustrated with the operation of the car sometimes. Especially coming from a Prius which hardly gets affected by the cold.
As I learned more about Li-ion tech it all started to make sense.
I read a lot about Tesla’s and there is a ton of info about battery management on their forums.


Sent from my iPhone using Inside EVs
 
Landshark said:
Charge rates are expressed as a decimal fraction of a batteries capacity. For Lithium, typical charge rates are .5C-1.0C with .8C being a common target.

We would need to know the voltage and amperage being supplied by the generator or regenerative braking in order to determine the C-rate.

I would imagine that the charge rate from regenerative braking/chevrons and the generator would be infinitely variable depending on SOC, braking force and throttle position.
Click to expand...

Since the Clarity battery is 17kwh, that corresponds with about C3 at 50kw.
To me that sounds very reasonable since you’ll only see the regen get that aggressive(going by power gauge on dash) under close to ideal circumstances like lower states of charge and mild temperatures.


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