Budget Battery Capacity Readout

Hi there. Long time lurker but haven't browsed in a while. This is an intriguing topic and got me curious to see what my capacity is. My guess o meter has been netting me 38 to 40 miles of ev range and I think it is because I live on a hill where I don't regen on the way down given I charge to full. I also don't have LRR tires. With that said, I think my capacity should be within expectation but wanted to check.

Before I invest in Vgate device, wanted to see if anyone in the southern California, orange county area wanted to meet up to test my battery and chat it up. Let me know... Just private message me. If not, no worries.

Lastly, BIG THANKS to all those that contributed to the effort.

 

Shockingly, my car, a 2019 Clarity with 52000 miles has a 53.8 ah battery. I’m still shocked. Was bought by a dealer from CarMax and flipped over to me.

IMG_1749 by Fe2_O3 posted Feb 2, 2024 at 4:44 PM

 

The battery capacity is only reset after a full (100%) charge starting from an SOC (state of charge) of less than 30%). If one has a 50 mile EV range (on the dash meter) after a full charge, a 30% SOC corresponds to about 11 EV miles left. Currently, I recharge our Clarity about five times a week to about an 85% SOC and the SOC rarely gets below 50%. We drive mainly on EV around our small town. We use HV on any trips longer than about 20 miles but such trips are rare (we have a gasoline powered car just for our longer trips, all well over 100 miles a few times a year). Once a year, or so, I let the Clarity battery run down to about a 20% and recharge to 100% SOC to reset the battery capacity. I started doing this just over a year ago with a new Level 2 charger. Before that, I had set the Honda Smart Charge to stop at 85% but at least once a month, Smart Charge would fail and the charge went to 100%.

Over the past 15 months, our battery capacity has went down from 50.06 AH to 49.96 AH. I think this is great. You can see the battery capacity data under user Leop. BTW, we bought the 2018 Clarity Touring in February of 2018. It was the first Clarity our local Indiana Honda dealer got.

 

I think my comments above about the battery capacity reset can be misinterpreted. I was speaking toward how the Clarity battery management system determines the battery capacity. Just like in laptop computer or cell phone, the battery mangement system measures the charge (coulomb counting) going into and out of the battery. To get the battery capacity (measured in amp-hours where an amp is a coulomb per second), the best way is to start with the battery at zero state of charge and end at 100% SOC. However, it is hard to start at zero battery charge as that hurts Li-Po batteries. But, if one knows the starting SOC, say X%, one can get the battery capacity by just normaizing the measured amp hours by 100%/(100%-X%). For batteries in general, one can estimate the SOC by looking at the open circuit votage. However, Li-Po batteries have a nearly constant OC voltage from 25% to 75% SOC which make it hard to estimate the SOC in that range. This is why one is asked to completely discharge (this gets the battery down to about a 10% SOC) a laptop or cell phone battery before starting a battery capacity measurement. The Clarity BMS works the same way and it is my experince that the Clarity BMS will take about a 30% SOC to enable a battery capacity measurement.

The other meaning of a Clarity battery capacity reset is when the Clarity BMS loses the battery capacity measure. Some say that this can happen when the Clarity has a some sort of a system failure. In that case, the battery capacity may be reset to the new battery capacity of about 55 AH.

I think that many higher than normal battery capacity values may be the result of the Clarity not being fully charged from an SOC of less than 30% for a long time. This can happen if a Clarity is recharged everyday but is not driven very far each day.

Leop

 

Thanks for that update. I also have disconnected the battery momentarily without causing a Battery Capacity Reset. This makes me continue to wonder what specific variables do cause that reset. I don't recall anyone on this forum specifically pinning that down.

 

Most things on a car that are expected to degrade (ie the fuel system, battery, engine, etc) are continuously "learning" or "adapting", sometimes only during certain conditions. Typically, this is gradual, and if the computer is seeing something that exceeds what it expects, it will usually enter a contingency, this sometimes is resetting the learning, sometimes it will go to a "base" setting. If I had to guess, this "reset" of capacity is caused either by a failure or accelerated degrading of the cell, that triggers the BCM to reset its capacity learning. The clarity, like almost any modern EV will perform cell balancing, and if a single cell is degraded, automatic functions will attempt to compensate. Probably with that is it isn't perfect, and one cell can drag down the entire pack depending on how degraded the cell is.

 

Tried this amazing tool today and loading the backup file loaded 3 dashboard panels of mostly empty stuff. Might have done it wrong but restored my backup and that worked well again. Made a few screens myself but definitely wanted to look at your handiwork.

 

Totally get that. I haven’t been able to make it work with my Mac yet because I think my vGate has given up the ghost, possibly by being connected to a faulty 3way connector. on the new one I'll disable the deep sleep and wrap a light electrical tape around it I guess to keep it better connected.

Has anyone tried it with a Mac yet? FWIW, I think these will be the Mac instructions I will try when the new vgate comes in tomorrow. will edit this post to confirm when I try it. posting here for others following.

1. Open Terminal
2. If Homebrew isn't installed, install it first:
   /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
3. Once Homebrew is installed, run:
   brew install blueutil
4. Wait for the installation to complete
5. Use system_profiler SPBluetoothDataType to list Bluetooth devices
6. Use blueutil --pair [MAC_ADDRESS] to pair
7. Use blueutil --connect [MAC_ADDRESS] to connect

To disconnect:

• Use blueutil --disconnect [MAC_ADDRESS] in Terminal
• Or click "Disconnect" in Bluetooth preferences

 

Ha! Well I'm not able to edit the old post - but the Mac Instructions are the easiest of them all. Disregard anything in Terminal.

1. Connect to the device in System Settings > Bluetooth like a normal device
2. the vGate iCar Pro BLE 4.0 for iOS/Android's Bluetooth is 1234 (very important, 0000 for others perhaps)
3. Must use Chrome, go to https://clarity-phev.github.io/powertrain_report/
4. Connect to the device, Load Data, Generate Report.

Congratulations on a really incredible platform you've built. Wish some of the github pages had better links and html instead of pdfs. there's one PDF that's just a link to a different page of a HOWTO that's moved that I wish were just a little easier to use. But those are mere dumb complaints to the major credit you deserve for building it.

 

Great news, congrats again on what you've built. I won't pollute your data on the official charts with what I have for now which feels ambitious. Still showing

HV Battery Capacity (A+B): 54.10ah
HV Battery Capacity A: 27.05ah
HV Battery Capacity B: 27.05ah

But I guess I might get news in the next 1000 miles? We'll see.
Odometer: 57380 mi.
Distance traveled since Battery Connected: 2179 mi.
Distance since DTC Cleared: 2187 mi.

Feels like I was clearing the DTC just a few days ago...

Thanks again for what you built for us. Saved me a couple hundred on a transmission oil change I was considering making at 60k until seeing this data. I do need to dive into the infotainment without CarPlay sometime again soon, but great to see it all out here.

 

I do realize that this reply is off-topic, too.

The brake fluid change is definitely by time. Brake fluid absorbs water even through the capped reservoir and hose lines. The Clarity brake system is too complex to consider not changing out the brake fluid every three years. I use a vacuum extraction system to do this twice, once with the Clarity in run mode and once with the Clarity turned off. The only time consuming aspect is getting all four wheels off the ground so the wheels can be removed.

The transmission fluid also appears to be by time, too, at least in most cases. Lubricating oils also affected by time as well has by heat. The Clarity transmission fluid lubricates the wet engine drive clutch and the reduction gears. Again, the Clarity (and other Honda hybrids) have a complex system. Changing out the transmission fluid every six years is not an expensive proposition especially for the average do it yourselfer.

LeoP

 

The manual is a bit cryptic on transmission fluid change; indicating it is driven by maintenance minder code 3, with no info as to what triggers that. However, it does have a note suggesting if you spend a lot of driving time in mountainous regions at low speed, higher xmsn temperatures abound and you should see to a change at 47,500 miles / 3 years. Dealer located records indicating mine was changed at 86k, about 10k prior to my purchase and I acceded to their recommendation to effect a subsequent change at 123k. Sounds like they took me for a "mountain man."