Budget Battery Capacity Readout

@Casey Martin ... You are doing better than me. I'm at 45.62 Ah with 42,250 miles (about 26,000 electric miles) also on a 2018.

 

How do you know how many miles were electric? I didn't explore all the lines on the Honda IDS. Maybe it shows that data?

 

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).

 

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.

 

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?

 

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?

 

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.

 

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.

 

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 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.

 

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).



As MrFixIt mentions, this data will only become more accurate the more datapoints are entered, so please continue to contribute!