Read Battery Capacity Yourself (Autel AP200 Breakthrough)

I notice in the spreadsheet that three of the seven lowest measurements are in Arizona. In terms of percentage of sales that seems hard to ignore as a factor. I can imagine that many of these cars sat on dealer lots for a long time fully charged in 100 plus degree weather. It's possible that the capacity was already diminished at the time of purchase. During PDI they are supposed to check the battery capacity, but even if they do as long as it's above 36.6 they aren't going to do anything, and they also don't seem to be under any obligation to record it anywhere or give this information to the owner.

I'm not sure what you can best hope for, either that the capacity doesn't drop much lower, or that it drops below 36.6 during the warranty period.

 

They indicated low to mid 40s when the car was new three years ago which seems a bit low to start out with, and now in the low to mid 30s. So that could mean it started with capacity already down a few percentage points, and then experienced more degradation over the subsequent three years, either at normal or a somewhat more accelerated rate. Driving in 100+ weather is probably not ideal, but at least the battery management and battery cooling system will be at work. And that will be true while charging also. But sitting out in the sun on a dealer lot all day in 100+ weather just seems like a potential problem. Especially since Clarity had a tendency to sit on dealer lots for a long time in states that did not have dealer incentives.

 

I agree that high temperatures can affect in those cases. Each owner situation is different, park at work in the sun all day, or in covered parking. Maybe only for an hour or so in the sun while shopping. Park at home in a garage or covered parking, or the car is parked on the driveway in the sun. Ambient temperature of 100+ is not great even in covered parking, but I am thinking it's much worse in the sun. We know that cabin temperatures can be 30 degrees above ambient, but I realize that's because of the windows. The battery is shaded so I'm not sure how much of the cabin and body heat and ground heat makes it to the battery when parked in the sun. I realize that the car is shading the ground underneath it, but the ground immediately surrounding the car is being blasted by sunlight and some of this heat might get radiated to the car.

There is also the theory that it's not great for the car to sit fully charged for a long time, although of course most people do that all the time if they follow standard charge to full protocol. So it probably makes little difference in most cases especially since we know that 100% SOC is not actually a full charge. But there is the possibility that if the car sits at 100% SOC in 100+ temperatures that this adds to the stress on the battery. Then again dealers were also notorious for not keeping the battery charged, so I don't know how likely it is that cars sat out on the lot in the sun fully charged.

In the case of Miles777 it sounds like the car is kept relatively cool while at home. Don't know how much time it spent sitting outside though.

 

For more background info, my Clarity was manufactured in Feb 2018. I bought it in Nov 2018 with 96 miles showing on the odometer. So it probably sat at at the dealer for many months, including the summer months. If the main battery capacity was tested during delivery preparation, I did not learn the results. It did have all but one of the Service Bulletins installed when I took delivery, and the dealer set up an appointment with me to have that remaining one installed a few days later (they had to order a part). I remember that it had a full tank of gas, and that there were single digits showing on the EV range when I drove it off the lot (it wasn't zero), so I promptly put it in HV Charge mode while driving home.

My 12 volt battery was replaced by the dealer under warranty at 19 months and 25,520 miles, when I was told that it failed their routine checkup while doing an oil change. Perhaps this fact indicates that the vehicle has been operating under heat stress. In Phoenix it's quite normal for a car's 12 volt battery to be replaced every 2 or 3 years, and few such batteries last for as long as 5 years. My car isn't typically parked outdoors, but even in my garage the ambient temperature can be above 100 degrees F in the summer.

 

Quite frankly, I'm not sure what to hope for either, but I guess it would be best if I got a replacement battery during the warranty period.

 

Hi guys. Been a while but wanted to update on my magic battery. About two months ago, the battery capacity finally started to change after a charge up from 24% to full. It went to 54.6, then two charge ups from below 30% later (I did not check immediately after the second charge up) it was 53.9kwh. Now after 4 more full charge ups from as low as 23% it still is tuck at 53.9kwh and it has been like this for at least 4 weeks now. I wonder if this truly is my capacity after nearly 4 years and 42,500km, at 90% EV? (entered into table)

 

for full charges to 100 (or 99%) from below 30% can only happen at home and I only have a L1 honda trickle charger. Don't have the time to wait at a L2.

However, I've mentioned before, anecdotally, I've found that the 15% SoC increments have taken less time and less kwh (read from EVSE's that report it when charging at public) since I first purchased the car. It is roughly 15% less time/kwh, which is in line with the average degradation around here. (I'm surprised that the kwh measurement in the clarity isn't more sophisticated as literally what I am doing is akin to measuring capacity as it's just a function of time/kwh vs. voltage.. and with li-on tables you can pretty much peg capacity at any point of charge by the input current vs. the rate that the voltage is increasing. Anyway.. it's definitely weird and it really puts to doubt how accurate the capacity readings are imo.

 

I think one of the theories is that something causes some people's battery capacity value to reset to 55. It then goes through a slow process of descending back down to the previous (and presumably accurate) value. Maybe part of the algorithm is to ignore or at least add little weight to measurements that have too much delta from the current value. So maybe the next test after the reset it calculates 48.0 or whatever, but it mostly ignores this and instead stores 54.8 or something. It might take a whole lot of measurement cycles to get it accurate again. Perhaps when they wrote the software they did not take into consideration the possibility of a reset to 55.0, especially if that itself is a bug.

No real incentive for them to fix this is there? A higher value is better for them as far as warranty. Not trying to get into conspiracy theories, but absent any information from Honda about this almost anything is possible.

Another concern someone raised is what if someone dropped below the 36.6 warranty threshold, then the dealer purposely did whatever it is that resets it to 55. I think that is probably going overboard in the conspiracy arena. But it may be possible that a service technician could inadvertently reset it while trying different things to "fix" the owner's complaints about battery range. Probably that's unlikely, but my suggestion is that if someone does reach the warranty number (I haven't heard of anyone even getting close so far), they should get a screenshot of it from Car Scanner. Then go to the dealer and don't say anything but ask them to check the battery capacity (even pay for it if necessary) and ask them for a printout. Having a printout in hand which shows a value below 36.6, say nothing to the dealer but instead contact Honda directly telling them that you are looking at a printout that you received from the dealer showing a battery capacity of less than 36.6.

 

So I did very rough calculations of the kwh readings between two 'ticks' of the SoC when the car transmits it (if you have the ACC on and the screen on the vehicle information display it will output the GOM reading whenever it transmits the tick). When I first bought the car it was approximately 2.4kwh or a total charge up of approximately 14.4kwh. Now it's approximately 2.05kwh or total of approximately 12.3kwh. Which seems inline. Also note the GOM is around 15% less than previous years as well for those good late summer days though this is of course much more variable.

As for 'slowly' going down, and for people who don't know of my situation. I've had this issue where the battery capacity stayed at 55kwh for basically 11 months when the car was three years old (and after a power system conniption and the service department disconnecting the 12 volt system to reset it). I unfortunately did not have the means to read the capacity before the conniption, nor between the time after the conniption and the 12 volt reset, so not sure what exactly caused the 55kwh reset value (I'm still working on the hypothesis that this value is false).

Finally what also bothers me is that the GOM requires at least SOME knowledge of the true capacity value to work properly. It does seem to be working properly as for round trips with no climate control it is stil surprisingly accurate, yet the capacity reading off the live data is completely wrong. And if honda has implemented any buffer algorithms (where it adjusts the battery buffer region more than just simply scaling) it requires a proper capacity reading as well.

 

this could be, but it's still pretty sophisticated... like it will change the estimation based on the temperature, which means it has SOME data on the battery chemistry. Also, without some information on the total capacity and battery management information the low end range estimation shouldn't be as accurate as it is. If they put so much thought in the GOM why couldn't they do the same for the capacity reading? Especially since it's a warranty issue. Anyway, Honda really makes you wonder sometimes.

 

Agreed, that's why I wouldn't recommend showing the Car Scanner screen to the dealer or to Honda, it's just for the owner's reference to compare with whatever the dealer's result is. The most critical thing if you know from Car Scanner that you are below 36.6 is to get a printout from the dealer's i-HDS system showing the value. I don't see any advantage to discussing the situation at all with the dealer other than asking for a battery capacity check, with no explanation why you want it other than you are just curious (not a lie because at that point you will be extremely curious!) In fact there would only be disadvantages to discussing it with the dealer. First of all the dealer isn't going to make the call on such a high ticket item, Honda will. And the dealer might gum up the works by attempting to "fix" a complaint about low battery range. Now we don't actually know if there is anything a service tech can inadvertently do (rebooting, software updates etc) that might cause the battery capacity to reset, but there is nothing to gain from letting them play around with it. You just want that printout in your hand from i-HDS showing that your battery is below 36.6 Ah before you say anything to anybody.

We also don't know for sure what Honda will say even with proof in hand, as we are only going by what the PDI sheet says about the 36.6 Ah warranty threshold. However I assume that this document is available on Honda Service Express, as I have seen a PDF of at least the 2018 Clarity PDI, presumably that's where someone got it from and presumably it's available for other model years as well. If so then there would be a credible explanation for how you obtained the document that you are using to claim that you are eligible for warranty. I'm not trying to be a worrywart, just considering the possible challenges that someone might face in this situation.

Although realistically this is probably a somewhat too early to discuss topic based on what we have seen with the charting, most likely if anyone does drop as low as 36.6 it will probably be towards the end of the warranty period at the earliest. Although there does seem to be some people who are under the 100,000 mile battery warranty who might get there within a couple of years. Currently the few battery replacements that I have heard of so far were the result of DTC's that popped up, at least a couple of which were the DC-DC converter. But apparently at least while under warranty they replace the entire IPU which in the case of Clarity consists of the 17 kWh battery and the DC-DC converter (itself a very expensive part). As Clarities eventually start going beyond warranty I expect there will be aftermarket refurb solutions for battery replacement, and probably the possibility of replacing just the battery or just the DC-DC converter since they are listed separately in the online parts websites. But we don't know any of this for sure just yet.

Of course for some current owners this is of no concern as they don't plan to keep their car past battery warranty. But at some point in the future there will be Clarity owners who either bought one new or used who will be discussing this topic.

 

So, is there a good place to buy an AP200, and is the Beta still available if I find one? My car is an outlier, a 2018 Base bought in April 2019 with 107K miles on it, so it would be really interesting to see where it's at for the extremes.