Budget Battery Capacity Readout

54.83 at ~4900 miles

 

I try to take a battery capacity reading each month and have recorded them in the spreadsheet about once a month since early March. For the first time this month (August), I got the same reading as the month before. I have an idea about why my battery capacity did not change in the past month while I have been seeing an average of about 0.06 AH per month. During this past month, the SOC never went below 30% (32% was the lowest). During the past months (before mid-July), there was one or more weeks where the SOC dropped to 30% or lower. I think that the BMS does not reset/measure the battery capacity unless the battery has a relatively low SOC (below 30%?) when the charging starts. I also think that the charging must be done to 100% (or near 100%) for the capacity tp be measured.

This is similar to laptop LiPo batteries. The capacity can only be reset when the laptop battery is nearly fully discharged and then charged to full (or near full) capacity. This is because the BMS algorithm needs to know how much charge (electrons counted by the coulomb counter) a nearly depleted battery takes to fully charge. Less than a full charge (low to high SOC) makes the battery capacity measurement inaccurate So, in those cases, the BMS does not reset the battery capacity..

The above may explain why those who "baby" their batteries (never getting relatively low of high SOC's) have unchanging battery capacities. The BMS never measures (or calculates) a new battery capacity.

One more observation is that the Clarity battery degradation is also time based and not just mileage and/or number of charge cycles dependent. Our 2018 Clarity was built in October of 2017 (the first build month) and has relatively low mileage. However, our battery capacity degradation is similar to Clarities with similar build dates but more mileage.

LeoP

 

Ordered this yesterday scheduled to arrive Monday.



I just downloaded the “Car Scanner ELM OBD2” app to my iPhone 12 Pro Max. I should be good to go, right?

 

The Vgate iCar Pro arrived today.

I could not get it to show up in my iPhone’s list of Bluetooth devices, but was able get it connected via the app.

Result is 46.62 Ah Battery Capacity. Dealer test right after delivery in Nov 2018 was 55 Ah. Seems consistent with the drop of 5 to 6 miles of EV range I seem to be seeing. Car is coming up on 3 years old and has 56,560 miles. Charged to full almost daily, rarely on anything other than the stock EVSE cable @ either 120 or 240v.

Next I’ll seek out the spreadsheet and input my data. Beyond that, I’ll probably just check the capacity annually starting Nov of this year.

Oh, and big thanks to MrFixIt!

edited to add: data entered on spreadsheet for both the 55.0 Ah when new and the 46.62 Ah now.

 

Thank you Mr. Fixit for the dashboard. I also got the vgate ipro and was able to connect using the car scanner app by switching the connection in the app to Bluetooth. The vgate instructions were a little convoluted. I will update the spreadsheet tonight. 2018 touring, 21k miles and I charge to full whenever I use the car no matter how little I have driven. I think I’m 80% EV over three years and only use HV on the highway when I know I will deplete the battery. Battery capacity is 48.9.

 

So like insightman, third time is a charm. I bought the Autel AP200, and could not use because my android is 32bit, and I already owned an older BT Vgate, so finally bought the one recommended in this thread. It arrived tonight. Battery capacity 49.12. Woo hoo, only a year of waiting, and I can read the capacity myself.

PS: to others who read the quick guide, if iPhone, you can use WiFi, select the WiFi network the device creates called VLINK, then the rest is same. There's a couple of models of this unit; one that does both Bluetooth and WiFi and a slightly cheaper variant that appears to be WiFi only (and labeled as such). I did the wifi only unit, but mine does not show up in Bluetooth. I have to select the wifi network VLINK or no gotty.

 

I tried using WiFi after the iCar Pro didn’t show up as a discoverable Bluetooth device in Settings on my iPhone. I got an alert about iOS 14.7.1 needing permission under Privacy settings, but that seemed to be on. What finally seemed to work was going back to Bluetooth but initiating the connection from the app, even though it didn’t show connected on my iPhone. I think. I predict I’ll have to grope my way through it again next time I try it.

 

I edited my original post, because I think its useful to know there are (or may be) different versions of this unit. There's one (like you seem to have) that has both bluetooth and wifi, and there's one that is wifi only. They're correctly, listed in Amazon, but if you do the wifi only model, then you may have to connect to the VLINK "peer to peer" wifi network that creates. I have no VLINK or similar in bluetooth to choose, because I bought the wifi only model...

 

I never saw vlink as an available Bluetooth connection on my iPhone. The only place it showed up was in the connection settings within the Car Scanner app itself (settings and then connections). By default the WiFi option is selected. Change that to Bluetooth and the device becomes discoverable.

 

FWIW, I posted on 8/13 (at 3970 miles) my first BC reading of 53.98 Ah, but I had not done a charge from completely depleted to full (call that a "full capacity" charge) for some time - maybe three or four months. Since then I have checked BC every other day just for curiosity (doing regular partial charges to full as appropriate) and there was no change at all, until today. I strongly suspect today's change was caused by doing a nominal full capacity charge (nominal because just before charging the EV range said 0 miles, but there were still two bars remaining on the battery gauge, indicating between 5 and 10% remaining SOC, over and above Honda's built in safety margin). It is possible that some other trigger (elapsed time? Accumulated miles?) caused the change in BC, but that should be easy to determine with continued observation. If doing a full capacity charge is the causative factor, it would be interesting to know the upper limit on the SOC just before plugging in to re-charge, above which a new BC value will NOT be measured and stored. Lots still to learn.
My BC reading today at 4119 miles is 53.82 Ah; now added to the spreadsheet.

 

I did not check this with Car Scanner itself. ie. maybe my unit also does BT, but I can say the OS bluetooth (settings on iPhone) cannot see it via Bluetooth. It did work fine via WiFi. When time permits, I'll check-- i.e. maybe it's there on mine too, and I just didn't do it correctly. Thank you for the specifics.

 

Personally I wasn’t paying that close attention but luckily got the BLE4.0. I looked back at Amazon and they had this handy note that I didn’t notice until today that was also not in the user manual that came with the device.

 

The SOC was at 25% when I charged this weekend. I just read the battery capacity and it was down from the July reading (50.56 AH to 50.50 AH). When I checked the BC a week ago, the BC was unchanged from the July 50.56 AH. During that interval (about a month), the lowest SOC was 32%. During previous monthly intervals where the BC went down, the SOC for some week was always less than 30%. Thus, I think that the SOC needs to go below about 30% for the BC to be recalculated after a charge.

Please note that I always charge until the charger stops (100% SOC) so I do not have a handle on what SOC needs to be reached to recalculate the BC. I do know that most laptops need to be fully charged from a near depleted state to reset the BC so I would assume that this is also true for the Clarity PHEV.

LeoP

 

Just wanted to make sure people search directly on Amazon for the vgate reader. One of the links in this article took me to someone selling for $65. When I searched directly, vgate was selling the same one for $32. (If you are looking for alternative. . . LE-link 2 that I already had for LeafSpy does NOT have enough buffer FYI)