Charging anomaly

MrFixit said:
It would not seem unreasonable to architect a modular system where each 'module' has a self-contained BMS. Although a critical (albeit non-trivial) function, it would seem that a BMS is a rather 'simple' piece of microelectronics when compared to everyday things like cell phones and microcomputers.
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I'm just an "armchair engineer" on this subject, too. All I know is what I read. What you say certainly sounds plausible, at least on paper, and perhaps in the future, EV battery packs will be made that way. It would add an extra layer of complexity because then the BMSs would have to balance charging/discharging not only between the different strings of cells in the module, but they would also have to balance between the different BMSs. I don't see anything there that appears especially difficult to control or program -- not moreso than what BMSs are already doing -- but then I'm not an electrical engineer, and it may be more difficult than we realize.
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Walt R said:
Sorry for not re-reading the full thread, but are you actually using the same energy to get your reduced range? If the battery capacity is reduced, you may be using the same energy/mi but stopping charging sooner. I know that's not the point of the thread, but I'm trying to keep you from thinking you're being penalized twice, if that's not the case. Your original post showed a lot of partial charges, so I don't know if you are correlating miles to kWh for charging.

I'm not a battery expert, so maybe this problem does consume more energy. But on basic principles, I wouldn't think that holding the voltage high and the battery not accepting it (thus no current) would create heat. But maybe there are inter-cell effects I am not familiar with.
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I see what you are saying. Assuming there is something wrong with the battery... It is possible that it is taking less energy to "fill" the battery with an estimated range of 40 miles than it was to fill it resulting in a 50 mile range. In either case if the actual range falls below our driving habits the car will begin to consume gas which is a penalty.
 
Hi jdonalds, I know you have been reporting what the car shows as estimated EV miles after charging. I assume that the actual driving EV miles have decreased, and not just the GOM number, right?
 
This is a question for Insightman. What estimated EV mileage range (as shown on the display) are you currently getting. I recall that you have an early Clarity. We also have an early Clarity and I want to compare estimated EV mileages (as best as can be done considering all of the variables).
 
At over 32,000 miles our range estimates seem to be increasing as expected as we go into warmer weather here in North Carolina and as far as I can tell are on par with last year. The OpenEVSE also shows normal charging curves.

Unfortunately our situation is a poor comparison to yours since we have far different usage. A typical day sees a quarter to half of a charge used at most, but every few weeks we have a weekend trip using mostly HV which accounts for our high mileage. So we have far fewer deep charge cycles than you do.

geo
 
leop said:
This is a question for Insightman. What estimated EV mileage range (as shown on the display) are you currently getting. I recall that you have an early Clarity. We also have an early Clarity and I want to compare estimated EV mileages (as best as can be done considering all of the variables).
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Yes, we bought our Clarity at the start of December, 2017. Of course, driving style has a significant effect on the Guess-O-Meter's projected EV range. My travel is split 50-50 between 70 mph on the e-way and 50 mph on country roads. With temperatures in the mid-60's I'm seeing 50-52 miles on the G-O-M. I'll be surprised if I don't again see 60 miles on the Meter when our delayed spring snaps into Michigan summer. On the rare occasions that I use up all the battery's available charge, I find the G-O-M is pretty accurate.
 
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My wife has had the car out of town for a few days, but as of last week temps are now in the mid to upper 80s and we're back up to 55 or so on the G-O-M. If everything is the same as last year that should continue up to around 58-60. With that being said temps this week are expected to be 10 to 15 degrees above normal so the AC usage may take it's toll.

geo
 
I also purchased my Clarity in December of 2017. With the temperatures around 70 I am getting 61 or 62 miles reported after a full charge.
 
Thanks for the last few reports. You are all seeing GOM numbers that I would expect.

We've had a week of cool temperatures in the 60s with rain. We are seeing 38-41 EV Range.

Our situation though seems to be changing. I still see charge graphs with some sawtooth patterns, but most charge graphs are smooth and flat. At the same time our range is reduced. If I were to guess I'd have to think we have a bad cell or two.
 
@jdonalds, hopefully there is minimal battery issues that do not effect your usage and enjoyment of the car. Eventually you may have enough battery degradation so you get a new battery from a warranty claim. You mentioned you bought new tires. Are the new tires also low rolling resistance tires? I do not doubt most of your missing range is due your battery issue but the question is how much.
However, it may make more of a difference than you think. The issue is that even regular bald tires have a lower rolling resistance than new tires even if you were going from regular to LRR tires. So if you did the reverse (LRR to regular tires) you are going to see a pretty big immediate difference comparing the end of life of LLR tires to the new life of non-LRR tires. The difference over the full life of both set of tires will not be as great but short term you may see a hit of more than a couple of MPG. Again, it seems clear there is some battery situation going on but I hope the impact will be less as time goes on.
 
The Gadgeteer said:
@jdonalds, hopefully there is minimal battery issues that do not effect your usage and enjoyment of the car. Eventually you may have enough battery degradation so you get a new battery from a warranty claim. You mentioned you bought new tires. Are the new tires also low rolling resistance tires? I do not doubt most of your missing range is due your battery issue but the question is how much.
However, it may make more of a difference than you think. The issue is that even regular bald tires have a lower rolling resistance than new tires even if you were going from regular to LRR tires. So if you did the reverse (LRR to regular tires) you are going to see a pretty big immediate difference comparing the end of life of LLR tires to the new life of non-LRR tires. The difference over the full life of both set of tires will not be as great but short term you may see a hit of more than a couple of MPG. Again, it seems clear there is some battery situation going on but I hope the impact will be less as time goes on.
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The car is still providing the desired outcome; that being driving on EV only around town. The problem will come next winter when temperatures drop and we will likely be forced to use some gas around town. As it is we came pretty close to running out of EV power over the winter just passed.

I bought the new tires on April 24. The problem started on April 17. The other indicator is the sawtooth charge graph which would not have anything to do with the tires of course.

If the tires were the sole reason for the drop in EV range that would be about an 18% drop. I remember changing tires on the Prius which caused a drop of about 2-3 mpg. Dropping from 48 to 45 is only a 9% drop.
 
Agreed. So about half of the lost range is due to the battery issue. So if it is linear, and it might not be, in the winter you are losing 3 to 4 miles range and maybe twice that in ideal weather. I would not be happy either. Your best bet for now is to keep a log and monitor for changes. This issue might end up happening to many others given enough time, miles, and charge cycles.
 
The Gadgeteer said:
Agreed. So about half of the lost range is due to the battery issue. So if it is linear, and it might not be, in the winter you are losing 3 to 4 miles range and maybe twice that in ideal weather. I would not be happy either. Your best bet for now is to keep a log and monitor for changes. This issue might end up happening to many others given enough time, miles, and charge cycles.
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Hard to say if it is just the battery capacity loss or a combination of that and the new tires. The thing is the range dropped before I had the new tires installed seven days later. The new tires are not rated LRR but there is no way to know how much the tires contribute to any additional loss. I did not notice any additional loss after the tires were installed.
 
jdonalds, can I ask what your usual climate control settings are? If your weather has been similar to the Sacramento area this past week, it's been cold and wet in the mornings -- a temperature setting of 70 will result in a lot of heat usage in the morning (I get surprised by that blast of heat the next morning if I movee the temp off of my normal Lo setting the day before to reduce the afternoon AC cooling). From what I can tell, the electric heat is a big battery drain, much more so than the AC. And the defroster (front especially) seems to be the biggest drain, as it probably uses the AC compressor AND some heat at the same time.

Driving conditions and style (especially speed) make a big difference -- my commute is half freeway (10 miles each way), and if I keep it at 65 just for that part the total EV range is easily 5+ miles more than if I drive my normal 75+ (both actual driving it out and the next day's EV Guess-o-Meter). I *really* wish Honda had given us direct instantaneous, averaged, and per-trip Miles/kWh measurements, instead of the stupid MPG data that's completely useless for a PHEV. I bet I'd see 3.5+ mi/kWh on local 40MPH roads, and 2.5 mi/kWh on the freeway at high speed. Right there that's the difference between 37 and 52 miles of range.

Ultimately, what we really need is a drive-off -- have 2 Clarities meet, charge fully, and go for a drive together in some set of conditions (including climate settings) and see how far each goes on EV. That would be the best way to see if your car is performing similar or worse than others. For extra nerd-points, if the results are consistently similar swap the tires on the 2 cars to see how much difference the LRR tires really make :-) If you were closer I'd do it!
 
The climate system is usually off these days. In the winter we used pre heat while plugged in. We may use the seat heaters.

The thing is our daily commute is fairly constant. We take our son to school, then pick him up. That alone represents the majority of our miles. Each leg is 12.5 miles so 50 miles per day just for school. That portion of our day doesn't vary. Also we have no traffic here so these trips don't vary. Our driving patterns don't vary in general.

The car began to creep up in EV range back in April with increasing ambient temperatures rising. I recorded 48 miles of range twice in early April. Then on April 18, still warm temps, it suddenly dropped 8-10 miles both in estimate and actual.
 
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