Budget Battery Capacity Readout

I track all the gallons of gasoline I put in the tank and assume 40 mpg (I keep a spreadsheet of gasoline purchases). This lets me say the rest of the miles are electric. Approximation, but probably pretty close. It's just a nerdy thing to do, but it lets me keep an idea of savings of electric vs gas and hours of operation of the gasoline engine (from assuming an average speed when running on gasoline).
 
Robert_Alabama said:
I track all the gallons of gasoline I put in the tank and assume 40 mpg (I keep a spreadsheet of gasoline purchases). This lets me say the rest of the miles are electric. Approximation, but probably pretty close. It's just a nerdy thing to do, but it lets me keep an idea of savings of electric vs gas and hours of operation of the gasoline engine (from assuming an average speed when running on gasoline).
Click to expand...
Same. I tried to also keep track of charging, but some public stations don't report the KwH, so I mostly gave up.
 
2019 base clarity, bought may 2019, 27000 km on it, 90% of them in pure EV mode.

Just bought a vgate ICAR 2 on Amazon, car scanner shows 48.88 Ah capacity.
 
Happy New Year [again], and thanks to everyone for their interest in helping to characterize the HV battery longevity of this great vehicle !!

Thanks to all, our data accumulation effort has been phenomenal! Don't forget to check out the results of this ongoing effort by examining the shared spreadsheet.

This year, A forum member who is very talented in statistical analysis has contributed a new graphical analysis viewpoint. There is a link to this from the shared spreadsheet, or you can get to it directly here: Thanks to Thomas Clauser !
Statistical Analysis Here

Here is a link to the Shared Spreadsheet. The Introduction Page has instructions and links to data entry and all of the graphical results:
Shared Spreadsheet Here

If you are already a participant, but haven't done a measurement for a while, the start of 2023 is a great time to pull out the OBD tool and add a fresh new reading to the data set !!!

:) Thanks again for all of the interest :)
 
I did an experiment yesterday. I drove 24 miles to an errand and back, 90% on freeways at speed limit (65mph) without switching to HV mode as I usually do. The starting GOM range was 62 EV miles with 100% charge as measured by ELM. After 44 miles the GOM hit 0.0 EV miles left, with two bars and 10% remaining battery per ELM. It automatically turned off EV mode, on the engine and kept the 10% charge the remaining 4 miles. Fortunately there were no hills and most remaining drive was street level so no strain on the car. BTW, the capacity still seats at 51.26 AH, with odometer at 31557. Funnily, after charging the GOM gives me 57 EV miles of range...
 
I need to get back and test my battery again. I can tell my range has dropped since last time (I'm at 66K miles now)

edit: where is the post with the step by step procedure to do this again? I have the app and scanner at home. Is there an updated special file I need to download to have the most accurate reading?
 
coutinpe said:
Funnily, after charging the GOM gives me 57 EV miles of range...
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The “GOM” is reactive. Run your experiment for a few consecutive days and the EV range estimate will settle in around 44-46 miles and your battery capacity will still be 51.26.
 
Does the calculated battery capacity drop in time regardless of the usage?

I first checked January 6 and got 48.88, now January 22 I get 48.80. I haven't used the car much since, only a couple hundred km max.

Does the computer just keep dropping the capacity based on the age of the battery?
 
victor_2019 said:
Does the calculated battery capacity drop in time regardless of the usage?

I first checked January 6 and got 48.88, now January 22 I get 48.80. I haven't used the car much since, only a couple hundred km max.

Does the computer just keep dropping the capacity based on the age of the battery?
Click to expand...

To be accurate, the capacity would be measured, rather than calculated.

Time, usage, operating conditions, storage conditions, charging conditions, to name a few will all have an impact on capacity.
 
victor_2019 said:
Does the calculated battery capacity drop in time regardless of the usage?
Click to expand...
We are only guessing precisely how Honda Engineering mechanized this... But,

It is certainly not just a function of time (without regard to usage). If that were the case, then everyone's curve would be a perfect straight line and they would all line on top of each other.

Be careful not to over-interpret the precision of this. In your example, 48.88 vs. 48.80 is an extremely small 'change' (less than 0.20%). Any measurement has some tolerance. You hardly used the car during this time, and to me the capacity number essentially didn't change either.

You need to look at this over the span of many weeks or months, not just a couple of weeks. I record mine every month or-so but it is not necessary to even do it that often. Unless you are especially technical, I would suggest recording your capacity every few months.
 
I agree there's no need to measure capacity in short intervals. For me it will likely be once a year. But I do think its relevant to mention that all batteries of every technology use an electrochemical process that itself degrades with time. The degradation process can be accelerated with things like high numbers of discharge and recharge cycles, or heat, but time alone does matter.

I think with EV batteries, the consensus is you might get an average of 10-17 years (so the useful life is long) but don't store your car even on a float charge for years and assume its capacity will be preserved.

There's a nice article on the subject here: https://www.pcmag.com/news/ev-batteries-101-degradation-lifespan-warranties-and-more

And of course, even when a EV battery does fail, there are usually options to get a remanufactured battery. There may be options short of buying a new battery pack from the manufacturer.

But yeah, I'm not paying real money for anyones 12 year old EV with original battery pack unless I know the cost of replacement and factor that in.
 
Reyn said:
My wife took the Clarity to work today. I will try to remember to take a photo and post it later tonight. But in the meanwhile let me give you the link to the mount i used.
Phone Mount, MOKPR Universal Car Mount with Long Arm Dashboard Windshield Car Phone Holder and Strong Suction Cup Car Phone Mount Anti-Shake Stabilizer Phone Holder for iPhone, Galaxy, Pixel, Moto etc https://a.co/2LBzNVI
Click to expand...
Looks like a pretty solid unit, beats one of these universal/multi-purpose ones:
image.thumb.png.b8a96b1a82a248f55c21f4b3283a1a44.png
:D
 
Is that held in place with chewing gum? It does appear that it will provide some impact protection in the event of a front end collision.

Some macadamia nut farmers in Hawaii cut old slaps into strips, fold them in half to form a small loop, tape it together with electric tape and use it to hold the nut while whacking it with a hammer. Tings you never know.
 
MrFixit said:
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@MrFixit could you update my readings? I am scared that I will mess up the database. My battery capacity readings (Clarity Touring 2021) have gone up to 54.80 (from 53.80 in September 2022). Odometer 10,214 miles. Since my last reading that I sent you, my 12 volt battery had drained (over the Christmas break while I was away for 4 weeks and I had forgotten to turn off the dash cam) which necessitated the use of a 12 volt Li-Ion jump starter. I did not take a battery capacity reading right after this.
 
Reyn said:
@MrFixit could you update my readings?
Click to expand...

OK, Done. Thanks for checking in...

It looks like you have been affected by the mysterious capacity "Reset". You may have read about this earlier in the thread. It is not possible for the HV battery to suddenly increase it's capacity so it is really a 'false' reading. Over time, (quite a long time) your reading should return to be back in line with the previous reading. Although we don't understand this completely, the working theory is that disconnecting (or draining) the 12V battery may cause this. We know if the disconnect is 'short' in duration, it does NOT reset the capacity. You could have had a drained battery for quite some time based on your description.
 
MrFixit said:
Happy New Year [again], and thanks to everyone for their interest in helping to characterize the HV battery longevity of this great vehicle !!

Thanks to all, our data accumulation effort has been phenomenal! Don't forget to check out the results of this ongoing effort by examining the shared spreadsheet.

This year, A forum member who is very talented in statistical analysis has contributed a new graphical analysis viewpoint. There is a link to this from the shared spreadsheet, or you can get to it directly here: Thanks to Thomas Clauser !
Statistical Analysis Here

Here is a link to the Shared Spreadsheet. The Introduction Page has instructions and links to data entry and all of the graphical results:
Shared Spreadsheet Here

If you are already a participant, but haven't done a measurement for a while, the start of 2023 is a great time to pull out the OBD tool and add a fresh new reading to the data set !!!

:) Thanks again for all of the interest :)
Click to expand...

Good day all,

I finally found some time to make some changes to the analysis focusing on forecasting an accurate capacity reading based on all the data (which can now be found on the second page).

This method takes the average capacity readings for each user in each mileage category (every 5,000 miles) that has at least 3 entries and performs a linear regression to predict what the capacity will be. (nerd note: the correlation coefficient of this data is 0.97 so it's very well attuned to the linear regression method). if there were any categories that did not meet the criteria, the forecasted capacity is used to maintain the continuity of the forecast. This can be seen for reference in the upper left hand chart.

In short, you can now enter any mileage you wish and see what the projected capacity in Ah will be based on the aggregate data. You can also enter your current capacity in Ah and your current mileage to see how you compare to the the total population.

in the example below, I've entered my current capacity (40.38 Ah) and my current mileage (55,000) and see that my projected capacity should be 47.06Ah
This is depicted on the chart on the lower left as follows:
Yellow = Projected capacity/Entered mileage
Green = Your entered capacity in Ah
Red = the 36.6Ah warranty threshold

You can also see where you current capacity should fall on mileage based on the projection. In my case my capacity is far below what should be expected. What this shows is that based on the cumulative data the average person wouldn't expect to see my capacity until at least 125k miles (don't worry, I picked mine up used a couple months ago and am definitely an outlier in the data).

upload_2023-2-24_10-25-16.webp

As MrFixIt mentions, this data will only become more accurate the more datapoints are entered, so please continue to contribute!
 
Thomas Clauser said:
I finally found some time to make some changes to the analysis focusing on forecasting an accurate capacity reading based on all the data (which can now be found on the second page).
Click to expand...

Hello Thomas - Thanks for making your excellent analysis tool even better !!

I would like to ask your opinion about some of the data (which I consider to be clearly anomalous) and may be having an influence on the statistics. There are 13 of these anomalous users currently. Some of them may already be excluded by some of your existing filtering rules. I consider these anomalous users to fall into 3 main categories. To find them, I went through all users and viewed each of their curves individually.

Category 1 - These users have had battery capacity "Resets". Something (perhaps a 12V battery discharge or long disconnect) caused these resets, and it takes a very long time for the reading to come back to 'normal'.
CLARITYDAVE1
LINCOMATIC
DANKS1
RANGAVASU1
KLIM1
JL-EV1 (probably a reset, but only 2 points so reset not completely apparent)

Category 2 - Implausibly high reading (typically only one reading that is implausibly high for the mileage)
EVA FARKAS1
JIMK1
VINCES1
DONNYD1
STACEY BURKE1

Category 3 - Questionable because of a 'perfect' starting measurement even though mileage was 'significant'
CIVAN1 ('perfect' at start, but with 12K miles)
ALTER1 ('perfect' at start, but with 22K miles)

Here is a graph of just these users (not all show well because of the default colors):
upload_2023-2-24_11-41-44.webp

In an ideal world, I might propose something like this:

Category 1 users - should be ignored while they are 'recovering' from the 'reset', but that is often an extended period and hard to identify unambiguously.
Category 2 users - should be always excluded (perhaps any single-point users with capacities greater than 54 and miles > 10K)???
Category 3 users - Not sure about these. Keeping them probably doesn't hurt much because there are only 2 of them...

What is your opinion about the impact of these users who's data clearly seems 'wrong' , and whether additional filtering makes sense?
 
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