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Discussion Starter · #1 · (Edited)
(UPDATE - This thread was started when the only known way to check battery capacity was through the dealer. The general information below about battery capacity is still valid, however starting in post #6 there is information about checking battery capacity yourself using an inexpensive and easy to use Bluetooth OBD-II device and smartphone app.)

A lot of people become concerned when their EV range is noticeably lower than when they first purchased their Clarity. Or if they feel they have never seen the high numbers that other people seem to get. Much of this is due to driving conditions and driving habits, which can vary greatly depending on where you live and how you drive. And in many cases it's because people are looking only at the instrument panel display, which is commonly referred to as the "guess-o-meter", after all it is just a predictor based on recent driving habits. Unfortunately the Clarity does not display anywhere on the screen actual EV miles driven. The only accurate way to check actual EV range is to pay attention to the odometer and keep track of how many miles you are able to drive in EV mode on a full charge before it gets to 0.

A lot of the complaints tend to come in this time of year because many owners especially new owners are not aware how much EV range decreases during the winter depending on what part of the country that you live in. The electric heater is a big part of this because it uses a lot of electric power to heat the cabin. Using the seat heater can help because it uses less electricity than the cabin heater, and it allows you to reduce the cabin temperature and still be comfortable.

There is a way to determine your actual battery capacity, but it's not something that you can easily do yourself (UPDATE - yes it is, see post #6 below). Probably most people know that modern cars store all kinds of diagnostic information in their internal computer, and that this data can be read by plugging into the OBDII port under the dash. For the Clarity one of the pieces of diagnostic information that it stores is the battery capacity.

What many people don't realize is that you can simply ask your dealer to check the HV battery capacity for you, which they can do by plugging into the OBDII port and reading this value. A new battery will have a battery capacity of 55 Ah (amp hours). Most people who have had their battery checked find that they have a value pretty close to this. If someone has actual loss of battery capacity compared to when they first bought the car then they will see a lower number, perhaps something in the high 40's, which would be around 10% loss in capacity. Honda will only replace a battery under warranty if the capacity has dropped below 36.6 Ah, which is a 33% loss of capacity. Unfortunately if the capacity drops below 36.6 Ah it will not put any messages on the screen or store a DTC code in the computer, so the only way to know if your battery capacity has dropped this low is to have the capacity checked.

Dealers will sometimes check the battery capacity for free especially if the car is in for other service. Some dealers charge to check it, I have heard of them charging over $100. And in many cases people find that the dealer is not aware that they are even able to check the capacity, or how to do it. In those cases it helps if you tell them that it's a line in their i-HDS system called Battery Pack Capacity, which is located in the Electric Powertrain Data List. You can also give them the screenshot that I have attached to this message, this screenshot is from Service Bulletin 17-093, Clarity Plug-In Hybrid: PDI and New Model Service Information.

Inexpensive OBDII readers like you get at your local auto parts store can read basic diagnostic data, however more expensive units costing in the hundreds of dollars are required to read more advanced data including the Clarity battery capacity (UPDATE - an inexpensive OBD-II device has been found which can read the Clarity battery capacity, see post #6 below). The i-HDS (Honda Diagnostic System) that dealers use is actually just a software that runs in Windows 10 and is available also to independent repair shops as a subscription based software. If your dealer insists on charging over $100 to check the battery capacity, you might try finding an independent shop that has the i-HDS software and they might check it for you for a lower price.
 

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And in many cases people find that the dealer is not aware that they are even able to check the capacity, or how to do it. In those cases it helps if you tell them that it's a line in their i-HDS system called Battery Pack Capacity, which is located in the Electric Powertrain Data List. You can also give them the screenshot that I have attached to this message, this screenshot is from Service Bulletin 17-093, Clarity Plug-In Hybrid: PDI and New Model Service Information.
2002, Does this apply to my 2019 Clarity?

Had the car at the dealer today for the 13,375 mi service (AO12) and asked them for "the Battery Pack Capacity printout that I was not given from the PDI". Told them "Elect PowerTrain page, Serv. Bulletin17-093", and the Serv Manager came back flummoxed. They couldn't find anything about it and he asked a couple of old guys ("one has worked there 25+ years" and we laughed when I said "this is a Clarity!") who never heard of it. He said they did a PDI, but I wonder if it was a common version for an Accord. I told him I would query you and send him the info. I'll send a copy of your screenshot.

Some history: My car had to be delivered from New Jersey to Lewiston Maine because the car that we were looking at Saturday evening, was sold by another salesman at 8am Monday morning. After sitting in the showroom for three months. It was driving out as we got to the dealer with our checkbook (they refused a CC). That was the only one available in Maine! Two weeks later ours arrived with 400 miles on it. Perhaps the PDI was done in NJ.

Once again thanks for your help, G-
 

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Discussion Starter · #5 ·
2002, Does this apply to my 2019 Clarity?

Had the car at the dealer today for the 13,375 mi service (AO12) and asked them for "the Battery Pack Capacity printout that I was not given from the PDI". Told them "Elect PowerTrain page, Serv. Bulletin17-093", and the Serv Manager came back flummoxed. They couldn't find anything about it and he asked a couple of old guys ("one has worked there 25+ years" and we laughed when I said "this is a Clarity!") who never heard of it. He said they did a PDI, but I wonder if it was a common version for an Accord. I told him I would query you and send him the info. I'll send a copy of your screenshot.

Some history: My car had to be delivered from New Jersey to Lewiston Maine because the car that we were looking at Saturday evening, was sold by another salesman at 8am Monday morning. After sitting in the showroom for three months. It was driving out as we got to the dealer with our checkbook (they refused a CC). That was the only one available in Maine! Two weeks later ours arrived with 400 miles on it. Perhaps the PDI was done in NJ.

Once again thanks for your help, G-
Yeah a picture is worth a thousand words that's why I recommend show them the picture whenever possible. Hopefully that will ring a bell when they see it.

The entire story is a little complicated. There are two separate things, the PDI checklist and the PDI instructions. The checklist they are supposed to fill out and leave it in the car. The instructions as the name implies gives the technician information on how to conduct the PDI items on a particular model.

Okay here's the complicated bit - the HV battery capacity check is not on the PDI checklist. Thus neither customers nor dealers typically know that it is part of PDI. But how to check the HV battery capacity is in the PDI instructions (it's the last item on the last page of the instructions). So it is not surprising that many (if not most) dealers apparently don't check the battery capacity since it's not on the checklist, and likely they don't read the instructions all the way to the end, they probably only look up something in the instructions if there is something they have a question about. Why the battery capacity check is not on the PDI checklist is yet another mystery about the Clarity that we will likely never know the answer to.

However since checking battery capacity is on the PDI instructions then in theory the dealer should check it, but even if they do there is no stipulation that they record the number anywhere or give it to the customer. All they are checking for is if the capacity is under 36.6 Ah which would mean it needs to be replaced. I can imagine that is a situation that is extremely rare on a new Clarity, if it has happened at all. If the battery was that shot on a new Clarity it would probably be throwing codes as well and they would know there is a problem anyway.

Nevertheless many people essentially "bluff" their dealer by telling them "You were supposed to check the battery capacity during PDI", as if they know for a fact that it wasn't checked. To give dealers credit they don't usually seem to argue, they just don't seem to know how as it is usually the first time they have ever even heard of it.

It's funny that you gave your dealer all of that info and they still don't know where to look, unless they couldn't figure out that you were talking about their i-HDS (Honda Diagnostic System). Giving them the picture should hopefully clear that up for them.

Service Bulletin17-093 was for the 2018 model, I would think there are versions for newer models but if so I don't know the numbers. But if you show them the screenshot hopefully the lightbulb will go off as to where in their system they are supposed to look.
 

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Just updating this for future searchers-- you can indeed check this at home easily with an OBD and app. My cheapest OBD doesn't work, but the $30 one I bought on Amazon for another vehicle worked with the app "car scanner'. I have the $4 pro version of that app, but I'm not sure that you need the pro version. There is a setting in the app for the clarity. The $30 one that I used to check this is an iCar Vgate Pro. I'm not affiliated with the app or the device. I just bought a used Clarity and wanted to know the state of the battery. I took a screenshot, you'll see my capacity is 50.48 Ah. On the next screen, it shows every single cell too.
Font Darkness Number Terrestrial plant Screenshot


660
 

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Hi,

can you please share the type of OBD you bought?, and what type of configuration steps (if any) needed to run the app on/with it. would be appreciated.
Sure. I used the
Vgate iCar Pro Bluetooth 4.0 (BLE)...
Purchased from Amazon for $30. I used the app called Car Scanner Pro (android, same may be available on iOS, I'm not sure).

I plugged in the OBD, turned on the car. Open and connect the app. Choose Honda Clarity as my car in the app. That is all ... No special config.
 

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Discussion Starter · #9 ·
Sure. I used the
Vgate iCar Pro Bluetooth 4.0 (BLE)...
Purchased from Amazon for $30. I used the app called Car Scanner Pro (android, same may be available on iOS, I'm not sure).

I plugged in the OBD, turned on the car. Open and connect the app. Choose Honda Clarity as my car in the app. That is all ... No special config.
After reading your post I ordered the Vgate 4.0 also and installed Car Scanner Pro. I have a 2018 with 17,000 miles and it shows my battery capacity as 53.64 Ah, a new battery is 55 Ah. My EV range seems about the same as when I first bought my Clarity so that number is about what I was expecting.

The free version of Car Scanner also shows the battery capacity, but it was only a few dollars to upgrade to pro and get rid of the ads. I found setting up the dashboard a little confusing at first but I eventually figured it out. If someone just wants battery capacity and doesn't want to set up a dashboard right way, you can go to All Sensors and then scroll through all of the different items until you find battery capacity.

On my Android phone's Bluetooth connection screen the Vgate appeared as two separate devices, Android-Vlink and iOS-Vlink. So it looks like iOS is supported also.
 

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Nice, glad it worked for you too. I didn't even set up the dashboard, just looked in the all sensors section. Mine is the same year as yours with a few fewer miles. My battery capacity was a bit lower than yours, but I tested it when it was kinda cold out. I'll recheck it when it's warmer. Mine was about 50.5, which is totally fine-- but it would be nice if it was a little higher. Either way, at this rate it'll still have plenty of range for a long long time.
 

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Discussion Starter · #11 ·
Temperature shouldn't make a difference in the number that it reports, the battery capacity shouldn't change, other than very slowly over time. From what I understand it runs a capacity check every so often, then it stores the result in the computer and it will report that same number each time you look at it, until the next time it checks the battery capacity. I'm not sure if it runs the capacity check every few weeks or after so many miles. Either way whenever it does calculate the battery capacity I would think it factors in the current temperature.

I don't know if it makes a difference but I only charge to full when I know I will be driving past my battery capacity. On days when I know I won't be needing the full capacity (which is most days) I only charge to around 80%. There is some evidence that staying away from 100% helps the battery to last longer. Now a full charge is not really 100% because the system keeps an unused reserve for that reason, so it won't harm the battery to charge to 100%. But over time it may possibly decrease battery capacity somewhat if it's charged to 100% every day. However unless Honda provides data specifically on the Clarity (which I doubt they ever will) there is no way to prove one way or the other, other than collecting battery capacity data from hundreds of Clarity owners to see if there is any correlation between battery capacity loss and charging habits. But for me it's easy enough to only charge to what I need so that's why I do, even if it's just a slim chance that it helps.

There are other reasons why one person might experience more loss of battery capacity than another. Very hot climates (example Phoenix) would be one possibility. I suspect another possibility is if the dealer let the HV battery completely drain during the several months that most of our cars sat on the lot. I don't mean just letting it get down to 0 EV range, which is common, but if it's already at 0 EV and then the car sits for several months it could drain the HV battery to full depletion which would not be good for it. Or it could be inconsistency in battery construction. More likely it's a combination of all the above, which makes it even harder to prove anything definitively one way or the other.
 

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I bought it used and am unsure of the previous owners charging habits. With our Tesla, we charge to 90% (used to be 80, but Tesla updated guidance) daily. With the clarity, I don't plug in nightly... Just charge it up at work. When I do charge it, I just let it go to "100%". My reason for doing so is that Honda gives no guidance and no way to set the max charge to a specific cap (like Tesla). As a small capacity battery (or, as a PHEV) the battery is set to not discharge to near empty or charge to near full, I think.

I thought I'd read that the capacity reading is affected by temperature. I stand, corrected! If it is anything like the Tesla, the capacity reading is based on calculations that require charging from a lowish state of charge to over 90%.
 

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Discussion Starter · #13 ·
I bought it used and am unsure of the previous owners charging habits. With our Tesla, we charge to 90% (used to be 80, but Tesla updated guidance) daily. With the clarity, I don't plug in nightly... Just charge it up at work. When I do charge it, I just let it go to "100%". My reason for doing so is that Honda gives no guidance and no way to set the max charge to a specific cap (like Tesla). As a small capacity battery (or, as a PHEV) the battery is set to not discharge to near empty or charge to near full, I think.

I thought I'd read that the capacity reading is affected by temperature. I stand, corrected! If it is anything like the Tesla, the capacity reading is based on calculations that require charging from a lowish state of charge to over 90%.
I would think that Clarity uses a similar method to calculate battery capacity, but with Honda they are very tight lipped about anything related to the hybrid system. Like they mention that it will sometimes do a "System Check" and start up the engine, but they give no indication how often it will do that. I have gone up to a month without the gas engine coming on, and when it did come on it was either because I purposely switched to HV or did a hard acceleration. So I know that it will go at least a month without doing a system check.

The only thing the owner manual says about charging is, "To help extend the lifespan of the battery, it is recommended that you fully charge the battery each time prior to driving". Okay but why? I could understand if they said that charging the battery to full will not reduce battery life, or maybe say that you should charge to full at least once a month, etc. But saying that you should always charge to full to extend battery life is a statement that really could use some explanation. I realize that the owner's manual probably isn't the right place to get into that level of technical detail, but as far as I know there has never been an explanation from Honda why they say that always charging to full will extend battery life.
 

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With that statement it is likely that they are limiting the max charge to the ideal level when we charge to "100%". Tesla also says that the ideal scenario is that we should charge fully every day... But by "fully", I mean to the preset max of 80 or 90%... Only charging to the actual full 100 before a long trip.
 

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Discussion Starter · #16 · (Edited)
With that statement it is likely that they are limiting the max charge to the ideal level when we charge to "100%". Tesla also says that the ideal scenario is that we should charge fully every day... But by "fully", I mean to the preset max of 80 or 90%... Only charging to the actual full 100 before a long trip.
Do you have a quote from Tesla on that? Not questioning I'm just curious if they are saying specifically that it is ideal for battery life to always charge to at least 80%, and if so why. The only reason that I can think of is that charging to that level decreases the chances of getting low on SOC, which apparently can also have an effect on battery life although to a lesser extent than charging to full. But if you know that you will only be driving twenty miles, is it still better for a Tesla's battery life to charge to 80% even when you don't need it?

As far as low SOC, I routinely drive my Clarity down to 0 EV miles. I use all the battery power that I can. I just don't charge more than I need to, even though according to Honda I am reducing my battery life by not charging to full every time.
 

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Discussion Starter · #17 · (Edited)
People over in this forum seem to be the ones that figured out how to parse the clarity info. Also, a number of people are posting their capacity, mileage, etc. Budget Battery Capacity Readout
Are they also posting their charging habits? Although it would still not be enough of a data pool to be definitive, it would at least maybe give an inkling if it has some effect.
 

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"To help extend the lifespan of the battery, it is recommended that you fully charge the battery each time prior to driving". Okay but why? I could understand if they said that charging the battery to full will not reduce battery life, or maybe say that you should charge to full at least once a month, etc. But saying that you should always charge to full to extend battery life is a statement that really could use some explanation. I realize that the owner's manual probably isn't the right place to get into that level of technical detail, but as far as I know there has never been an explanation from Honda why they say that always charging to full will extend battery life.
This is only speculation on my part, but perhaps the key words in this recommendation are "prior to driving", rather than "fully charge". That is, maybe it is hinting at "when" to charge, rather than "how much", to help extend battery life?

That would be consistent with the advice in manuals for Li-Ion battery powered shop and yard tools that I have - those advise that Li-Ion batteries will last longer if not stored either fully charged, or near fully depleted. That is, storing at some level of partial charge seems to better prolong battery life. Of course such hand tools might normally go unused for a half year or more, or for some users never longer than a couple of days, so what periods of disuse qualify as "storage" is somewhat nebulous - perhaps the randomness of each application makes it impossible for manufacturers to say.

With that in mind, my interpretation of the above sentence is that it is better to "fully charge" closer to the beginning of your next drive, rather than, say, to "fully charge" immediately after your last drive. If this interpretation was Honda's intent, then while technically correct, it is still poorly worded, because if you end up near 0% SOC at the end of a longer drive, you would want to promptly charge the battery, but if you don't plan to drive again for more than (some time period, assumed to be between a day or three), then that's where they should clarify that doing a partial charge might help to extend battery life, but do remember to complete a full charge just before your next drive...

On the other hand, with efficient battery management including temperature sensing and active cooling, the difference in battery life between normal practice and optimal practice (whatever those mean) might be small enough that it only warrants an off hand imprecise comment in the manual? :(
 
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