Budget Battery Capacity Readout

Thanks @Danks !

I was just catching up on this thread after being away for a bit and the #1 item that seems to kill the battery is heat, even with the Clarity's active cooling.
My battery capacity situation is very similar to what @Miles777 had experienced with his 1st Clarity. Both of us live in the desert southwest with temps hitting 115+

Here are my readings.

08/09/2025 48,414 mi 41.26
10/30/2024 43,858 mi 41.72
01/25/2023 29,474 mi 44.64
07/15/2022 25,560 mi 45.58
03/24/2021 21,888 mi 47.40

I bought my car in Sep 2018 which means the battery warranty should be thru Sep 2026.
It is going to be an interesting race between time and heat.

On another note - it seems that Honda or the dealer is trying to wiggle out of Warranty on used cars
https://www.clarityforum.com/thread...standing-or-is-honda-not-honoring-terms.1920/
 
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lanb said:
Thanks @Danks !

I was just catching up on this thread after being away for a bit and the #1 item that seems to kill the battery is heat, even with the Clarity's active cooling.
My battery capacity situation is very similar to what @Miles777 had experienced with his 1st Clarity. Both of us live in the desert southwest with temps hitting 115+

Here are my readings.

08/09/2025 48,414 mi 41.26
10/30/2024 43,858 mi 41.72
01/25/2023 29,474 mi 44.64
07/15/2022 25,560 mi 45.58
03/24/2021 21,888 mi 47.40

I bought my car in Sep 2018 which means the battery warranty should be thru Sep 2026.
It is going to be an interesting race between time and heat.

On another note - it seems that Honda or the dealer is trying to wiggle out of Warranty on used cars
https://www.clarityforum.com/thread...standing-or-is-honda-not-honoring-terms.1920/
Click to expand...
Add me to that list. Bought the car new in Jan 2019. First time I measured the battery capacity was after seeing a dramatic loss in range in the summer of '22 after moving to Vegas, it was reading 52 Ah. It kept like that (reading it every month) until the following summer, when it suddenly dropped to 50.72. Same thing again the following summer, dropping to 49.7 and stayed like that until I moved to Phoenix early in 2024, but there was no noticeable change until midsummer, when it suddenly dropped to 49.2. Now when I last read it in July it was already sitting at 48.7, but in recent days I noticed a sharp drop in range again (from 48 to 41 miles). Haven't had the chance to measure the battery yet, but I wouldn't be surprised to find it at 47 Ah or less.
 
lanb said:
Thanks @Danks !

I was just catching up on this thread after being away for a bit and the #1 item that seems to kill the battery is heat, even with the Clarity's active cooling.
My battery capacity situation is very similar to what @Miles777 had experienced with his 1st Clarity. Both of us live in the desert southwest with temps hitting 115+

Here are my readings.

08/09/2025 48,414 mi 41.26
Click to expand...

I'm in Florida so 6 months in the nineties but never over 100. I have also noticed more degradation during the summers, about twice as much as winter, but not near as bad as you.
I'm at 101k miles on my 2018 with the battery at 44.2. The rate of degradation was greatly reduced year round starting 2 years ago when I changed my charging habits. I now minimize the time the car is sitting at 80-100% and 0-10%. I charge to around 80% over each evening, then start charging again in the morning while I have breakfast etc then drive away before its 100%. Over the last 4 (hot) months I drove 4000 miles and it went from 44.50 to 44.21. I still get about 54 miles actual (no highway) from a full charge even with cheap crappy walmart non-ev tires.
 
I think it is pretty cool that these cars are still getting 50+miles of battery range if driven 40-50 mph. I don't have the patience to manage the charging level on the Clarity, and I'm a little behind @David Towle at 43 Ah with 70k miles, but I can still surpass 50 miles on EV when not driving at highway speeds. But, if you have the time and patience to manage the charging on the Clarity, I am sure it is good for the life of the battery to do so.
On a full EV with say 300 miles of range with onboard software to set the charge limit, this is much easier to accomplish on a daily basis (it essentially manages itself). I rarely need full battery during the week on the EV, so I set the limit to 75% and usually charge once a week to bring it back to 75% when it drops to about 40%.
 
Robert_Alabama said:
On a full EV with say 300 miles of range with onboard software to set the charge limit, this is much easier to accomplish on a daily basis (it essentially manages itself). I rarely need full battery during the week on the EV, so I set the limit to 75% and usually charge once a week to bring it back to 75% when it drops to about 40%.
Click to expand...

We also have a full EV, A Tesla Y, and agree it is much less effort to manage the battery. Although the difference would not be as bad if the Honda app had the functionality of the Tesla app.

One key to still getting high miles per charge on the Clarity is to minimize the use of regen. Once you've accelerated, coasting is a much more efficient use of the power.
 
David Towle said:
I'm at 101k miles on my 2018 with the battery at 44.2. The rate of degradation was greatly reduced year round starting 2 years ago when I changed my charging habits. I now minimize the time the car is sitting at 80-100% and 0-10%. I charge to around 80% over each evening, then start charging again in the morning while I have breakfast etc then drive away before it’s 100%. Over the last 4 (hot) months I drove 4000 miles and it went from 44.50 to 44.21.
Click to expand...

Correlation doesn’t mean causation. We know that degradation isn’t linear. Laboratory testing has demonstrated that for us. Multiple variables need to be considered.

As an example, discharge rates and conditions are as much of a factor as charging habits. Often times we have very little control over discharging the battery. In cold weather at high speeds or in hilly terrain the battery could be depleted in 15-20 minutes. That’s a rapid discharge which is not ideal for battery longevity.

Didn't you relocate from New England to Florida a couple of years ago? Was that about the same time that you also changed your charging protocol? You also changed the climate and terrain where the vehicle is operated. Quite likely your driving patterns changed as well. Combine just the few variables mentioned thus far, with the high probability that you saw the most significant levels of degradation within the first year or two of ownership and you may come to realize that what you’re measuring now is just baked in the Lithium cake, regardless of the subtle modifications you’ve made to your charging regimen.
 
Landshark said:
Correlation doesn’t mean causation. We know that degradation isn’t linear. Laboratory testing has demonstrated that for us. Multiple variables need to be considered.

As an example, discharge rates and conditions are as much of a factor as charging habits. Often times we have very little control over discharging the battery. In cold weather at high speeds or in hilly terrain the battery could be depleted in 15-20 minutes. That’s a rapid discharge which is not ideal for battery longevity.

Didn't you relocate from New England to Florida a couple of years ago? Was that about the same time that you also changed your charging protocol? You also changed the climate and terrain where the vehicle is operated. Quite likely your driving patterns changed as well. Combine just the few variables mentioned thus far, with the high probability that you saw the most significant levels of degradation within the first year or two of ownership and you may come to realize that what you’re measuring now is just baked in the Lithium cake, regardless of the subtle modifications you’ve made to your charging regimen.
Click to expand...
We relocated 5 years ago. Had plenty of data in Florida before the change in charging. No changes in driving conditions in the last 5 years.
 
coutinpe said:
Would charging in very high ambient temperature also help degrading the battery?
Click to expand...

Yes. Let’s first remind ourselves that charging the battery under ideal conditions degrades the battery as well. In a nutshell, everything causes battery degradation.

That said, Honda, like most manufacturers, employs a battery cooling system in addition to a Battery Management System (BMS) which protects the battery by regulating charging and discharging. If you are able to charge the battery, Honda has determined that it is acceptable to do so.

Will regularly charging at 135F rather than 77F degrade the battery at a more rapid pace? Probably. Good luck measuring that. Besides, what options do you have? Are you going to leave the car in a climate controlled garage during the 6 months of sweltering heat?
 
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