Honda Clarity Forum banner

2018 Clarity sudden change in behavior

1819 Views 13 Replies 9 Participants Last post by  bikematt
We have a 2018 Clarity which is mostly used for daily local driving with the occasional longer distance trip. We have brought it in for all recommended services at the dealer including a recent one. The car has not given us any problems to this point. We have a Chargepoint Level 2 charger in our garage.

Generally, when traveling a longer distance trips, the behavior is that the battery runs down to two bars then the gas engine starts running much of the time. This makes sense.

Yesterday, this behavior changed. At about 35 miles out on the highway, I was using their adaptive cruise when I came up behind a rather slow vehicle. I moved to overtake, and instead of the car speeding back up to the limit, it lost significant power to the point I felt the need to press on the accelerator aggressively. When I did so, the engine came on very loud, much louder than I ever remember, and the car recovered speed. The engine stayed on very loud and the battery charge dropped to one bar then zero bars. I have never seen the battery go below two bars. I pulled off at the next rest stop, shut down and restarted, and used the HV charge mode. The battery did charge seemingly normally. We got to our destination before the charging reached its limit.

On the return trip the same thing happened but I wasn't overtaking. The battery again went to zero bars with the engine loud. I went back to HV charge and completed the trip. The battery reached 60% charge (as reported by the app) and a message was displayed that charging was stopped and could be completed with a charger.

Conditions were nominal. Not especially cold, not using heated seats, nothing unusual.

My question is, is this normal, perhaps the dealer updated software, or is something wrong and needs immediate attention. As I mentioned, this is the first time I have seen the battery charge go to zero bars.
See less See more
1 - 14 of 14 Posts
This is unusual to say the least.

Never have I seen the charge bars go below 2 bars.

I have had the engine rev up like buzzing hornets but that's because the battery ran out (2 bars) and the A/C was running on high.

Might be worth taking it to the dealer for a diagnostic ?
I never let mine go below about 50% SOC, when on the highway (using HV), for just the reason you've shared.
We have a 2018 Clarity which is mostly used for daily local driving with the occasional longer distance trip. We have brought it in for all recommended services at the dealer including a recent one. The car has not given us any problems to this point. We have a Chargepoint Level 2 charger in our garage.

Generally, when traveling a longer distance trips, the behavior is that the battery runs down to two bars then the gas engine starts running much of the time. This makes sense.

Yesterday, this behavior changed. At about 35 miles out on the highway, I was using their adaptive cruise when I came up behind a rather slow vehicle. I moved to overtake, and instead of the car speeding back up to the limit, it lost significant power to the point I felt the need to press on the accelerator aggressively. When I did so, the engine came on very loud, much louder than I ever remember, and the car recovered speed. The engine stayed on very loud and the battery charge dropped to one bar then zero bars. I have never seen the battery go below two bars. I pulled off at the next rest stop, shut down and restarted, and used the HV charge mode. The battery did charge seemingly normally. We got to our destination before the charging reached its limit.

On the return trip the same thing happened but I wasn't overtaking. The battery again went to zero bars with the engine loud. I went back to HV charge and completed the trip. The battery reached 60% charge (as reported by the app) and a message was displayed that charging was stopped and could be completed with a charger.

Conditions were nominal. Not especially cold, not using heated seats, nothing unusual.

My question is, is this normal, perhaps the dealer updated software, or is something wrong and needs immediate attention. As I mentioned, this is the first time I have seen the battery charge go to zero bars.
My 2018 Clarity displayed similar issues about a year ago. I disconnected the negative terminal from the 12 volt battery for around 15 minutes and then reconnected it. The issue has not returned. I'm guessing the computer wanted to be rebooted.

BTW... All of the warning lights on your instrument panel will illuminate like Times Square on New Years Eve. After driving about 1 mile everything reset and the warning lights went out.
I have seen the engine start with three bars on the battery. Never seen it drop below 2 bars...
LenH, that's interesting.

We did bring it in to the dealer. They found no stored DTCs and drove it around and found nothing abnormal. Obviously they didn't drive it until the battery was depleted though.

I'm wondering if I should do a reboot like you did or wait until it happens again? I didn't speak to the tech but he may have issued a reset command.
Be sure you get the radio/navigation code if you have a Touring. I am sadly not able to retrieve ours online. I am missing the serial # card...
Be sure you get the radio/navigation code if you have a Touring. I am sadly not able to retrieve ours online. I am missing the serial # card...
I did not need to reset my radio code. I have a 2018 Touring.
  • Like
Reactions: 1
This sounds like a failing battery cell. I've seen my wife's Clarity drop to 1 bar from mountain driving and the result is that the engine races and you have no power. The fact that yours dropped quickly is a sign that either the battery has one or more failing cells or the computer that manages the battery is failing.
Yesterday we drove 5N/5S to Bakersfield and back home here in the San Gabriel Valley. Both ways we stopped at the Tejon Outlets and got some EV charge. On the way home we were able to charge for some 40 mins. I drove up the Tejon Pass 5S on the way home and in a little while used up all the charge in the battery, all the way down to empty, just like in your video. I noticed RPMs were just past the middle bar on the RPM gauge. Having just recently changed the oil and engine air filter I was happy with the way the engine ran, maybe 65 to 70 MPH. It does seem to have something to do with the RPMs reaching at or above that level. Later still in the mountains the car kept 2 bars on the battery as normal, (never reached the half way bar in the center top of the gauge. (I couldn’t take a video/picture for safety)…
With our 2018 Clarity, I've noticed the 0 bar situation several times when traveling to a frequent destination in the foothills east of here. Up and down 1000 feet or more. Seems to go to zero bars and then on the first down stretch gains enough charge to have at least 3 bars after which it pretty much maintains the 2 bars (or more). This trip has always run out of EV charge, but closer to the destination but never looked closely at the charge bars until recently. Don't know if this is normal, but it makes some sense to me when thinking about the whole EV/HV charge management issue.
I think this is normal. when you go downhill my car charges up too. Use the left paddle on downhills.
1 - 14 of 14 Posts
Top