Main Battery Life Indicator

  • Thread starter Thread starter Donald Rapp
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Donald Rapp

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There are two indicators. One is the digital miles remaining. I talked with Honda Central. This does not (I repeat NOT) tell you the charge of your battery. It does a computer calculation, based on past recent driving of how many miles you can expect if you drive the same way. And by experience, it is usually wrong. The other indicator is the bar chart at the left of the dashboard. This does tell you the relative charge but it is not specifically quantitative. I have a 2018 Clarity with 27,000 miles. The digital display might say 35 miles, or sometimes 39 miles when the bar chart is at the top. Experience teaches that even though the digital display might say 35 miles after fully charging, that is an underestimate. The bar chart still shows lines even when the display shows 0.0 and I can keep driving for at least seven miles with digital at 0.0. Conclusion: Don't trust the digital display. Rely on the bar chart.
 
This does not (I repeat NOT) tell you the charge of your battery. It does a computer calculation, based on past recent driving of how many miles you can expect if you drive the same way. And by experience, it is usually wrong.
You are correct that it is based on performance during your past recent driving. It is impossible for the vehicle to predict the energy demands of a future trip. If, in your experience, it it "usually wrong", that means that your driving pattern is not consistent from day to day. With a consistent driving pattern, the EV range estimate is actually very good in my experience (2018 Clarity, 40,000 miles).

Because of the ambiguity of the EV range and varying driving patterns it is best to determine the health of your HV battery by querying the actual capacity (as measured by the vehicle itself). The warranty is based on this capacity measurement. Honda dealers can do this (but they may not know how, an they may charge you a fee). It is not hard to do this yourself. Detailed instructions can be found here:
https://github.com/clarity-phev/Battery-Capacity-Read
 
I’ve driven for hundreds of miles through the mountains in Northern California with EV range at 0.0. The Clarity has a reputation for behaving differently for different owners.

At EV 0, which coincidentally occurs when the battery gauge has 2 bars remaining, the ICE always triggers. I’ve never seen less than 2 bars on the battery gauge under any circumstances.

Regardless of the EV range estimate when fully charged, it could be 35 or 55, that number will drop in relative harmony with the battery gauge, reaching 0 EV miles and 2 bars like clock work.

The last 2 bars on the gauge represent a bottom end “buffer” which Honda implemented to protect the battery from being completely discharged. There is also a top end “buffer” which remains invisible to the owner as far as being seen on a dash display. It would probably be disturbing for owners if the gauge only displayed 19 of the 20 available bars when fully charged, however, Honda limits charging to approximately 90% of what the battery is capable of accepting.

We’ve also learned that operating the vehicle with the battery gauge at 2 bars does not produce the most pleasant driving experience. That said, it is often recommended to engage HV mode when the battery gauge shows 4-5 bars, which may correspond to an EV range estimate of 5-10 miles, in situations where the journey will exceed the remaining EV range.
 
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