Battery fully charged but running in full motor/gas mode?

With a full battery, either aggressive acceleration or aggressive braking will trigger the ICE to run. You are either demanding more power than the batteries alone are capable of providing or sending more regenerative energy to the battery than it is capable of accepting. Once started, the ICE will run through a “warm up” period. This may take 3-5 minutes.

If neither of those descriptions match your driving habits, the car may be functioning inappropriately. It should default to EV mode upon “start up”.

If your Honda service person believes otherwise, we have yet another example of a Honda service person who does not have even a rudimentary understanding of the vehicle.

 

Be more patient... In my experience it is 'normal'.

As @Landshark stated, it will do this occasionally. It will also do this sometimes for no apparent reason at all (it is some kind of maintenance function). Just ignore it and continue driving. It WILL turn off the ICE and go back to EV mode. It sometimes 'seems' like a long time, but it has never failed to go back for me.

I would recommend against trying to force it by re-starting, etc.. It is doing this for a reason, and you should allow the vehicle to execute the maintenance function without interruption.

 

This ^. Once the gas engine starts, you want to let it get up to temperature before shutting it off. To do otherwise is not good for the engine.

 

I hate it too, as the braking near my house often trips the ICE, especially in winter. I then drive around town for a few miles without using EV, returning home with a still fully charged battery (face palm).

Other than avoiding heavy braking, you can choose to avoid charging fully....

 

How do you manage to not deplete the battery, at least some, on that trip? Doesn’t the uphill return use some capacity?

We have a half mile of downhill in either direction from the end of the driveway. One option is 9%, the other about 6%. I usually start out slow and let the built in regen control speed, which minimizes braking for the right turn near the bottom. I’ve yet to trigger the ICE.

It’s 700-800’ feet down to the valley floor, some ups and downs along the way. Usually no range is lost for the first 4-5 miles. The return, however, uses ~8 miles of range.

Have you ever, not charged after one of those short trips? The battery has to be depleted at least a few percent. It sounds like a trip that could be completed at least a half dozen times on a single charge.

 

One other note is that you are in 'normal' mode which means you are not in ECO (the leaf symbol on your dash display) nor in 'SPORT'. Sport mode will be the easiest to accidentally trigger the engine to come on during acceleration. Next is Normal mode. But in ECO mode you actually have to press the accelerator past the detent that you can feel as you apply more and more travel to the pedal.

But as the others have mentioned, the engine can be triggered during regen braking a full battery, particularly in cold weather (say below freezing). When it is in ECO mode it should revert back to running off the EV battery once the engine finishes the warming up process (a few minutes).

 

It is mostly flat, but several starts/stops within the first mile. The first or second stop usually triggers the ICE if charged to 100% and temps are under say 45*F. It then runs the ICE for most of the remainder of the 6 miles or so that constitutes the quick run into town and back. Above roughly 45 it does not do it nearly as much.

I dont charge when I get back- per above it's still fully charged or close (and likely to do it again next time I leave). I try to stop overnight charging around 95% or precondition (without charging) in am to draw it down some, but don't always think of it. I also will admit sometimes it's from my habit of hitting the paddles (no no when full and cold) - miss the high regen B drive mode in my Fit EV and none of this nonsense.

It's frustrating that at the time I need to use EV most for efficiency it won't.

 

I feel there is a rationale for not 'stopping' the charge prematurely like this. If your EVSE can monitor charging parameters, you will find that the charging current doesn't just terminate when the charge is complete. The current (during the last 5 minutes or-so) gradually tapers off. I believe this is the time when the individual cells are being balanced. If you always terminate the charge early, it is possible that the cells do not get balanced properly and there could be some long term impact.

 

In 2020 Clarity ice does not kick in no matter how hard I break.

 

Do we know this to be the case or do we just believe it to be the case? Are you simply observing the characteristics of a standard charging protocol? When does cell balancing occur? At the tail end of every full charge cycle? Throughout the charge cycle? Every 3 months? Every 15th charge? When deemed necessary?

I’ve heard that Tesla recommends to not charge above 80% for daily commuting. This seems to be a fairly common practice among Tesla owners and even some Clarity owners. Are these owners only balancing their cells when they fully charge for a long trip? How often is cell balancing necessary?

For the lithium batteries that I just installed in my motorhome, the recommended procedure was to fully charge them separately, prior to installing them in a series/parallel configuration. I did this with a charger designed specifically for lithium batteries. After that, I can use them anywhere from 0% to 100% for years on end. The batteries have a built in BMS. There is no mention of fully charging them on a regular basis to balance the cells.

I don’t know for a fact whether or not limiting a charge to 90-95% will be a detriment or benefit to the battery. Perhaps if the charge is limited to 90%, the BMS will balance the cells from 88-90% SOC. Have you observed the charging current under those conditions? And does reduced charging current indicate that cell balancing is occurring?

I’d wager if JFon101231 limited charging to 90%, it would eliminate the ICE from triggering during the first mile of his drive. That might benefit the car over the long term as well as his sanity.

 

Is that with fully charged batteries?

 

We do not know this... It is just a guess on my part.

 

Not charging to full I think is the best strategy to avoid the full battery with regen braking engine start problem. Reverting to engine braking when the battery is full is commonplace in "regular" (non-plug-in) hybrids, because it is easy to over-top the much smaller HEV battery on a downhill run. Plus it is a given that the engine will run every time you drive a regular hybrid.

In the PHEV Clarity, I have to dodge this bullet daily, as the first part of my drive is 1/4 mile downhill to a stop sign. An alternative, if the battery is full, is to shift to neutral, which defeats the regen braking and freewheels, relying on the friction brakes to stop. I would NOT advise doing this except at low speeds. In my case, I roll down a gentle hill at about 20mph in neutral, stop at the stop sign, shift back into drive, and then go. My next stop is about 3 miles away at 55mph, which seems to burn enough off the top of the battery that I can stop normally without waking the gas engine.

 

But the Honda Insight and Accord hybrids don't burn gas to use up excess electricity like the Clarity does. Of all the things I want Honda's engineers to explain fully, this strategy is at the top of my list.

 

My car USED to behave as the first few replies described,. it was brief and seemed normal. However I have since had a change in behavior.
- It is no longer brief, it will keep the ICE running my entire 26 mile commute IF I did not stop, turn off power completely and restart.
- The trigger is the brake paddle. When the battery is FULLY charged,. if I pull the brake paddle in the first few minutes of driving, it WILL turn on the ICE and that is the beginning of the end of battery driving until i shut down and restart.

 

I have recollection of somebody reporting a false indication of ICE operation (the instrument panel dial turned all white as though the engine was on). In reality, it was not running (or it did shut off) but the dial indication persisted until a restart.

I'm sure with a 26 mile drive, you were certain it was actually running. I never use the paddles, but maybe I'll try this to see if I can duplicate it... What year is your Clarity?

This old thread has a very similar discussion about the all-white display even when the ICE is not running...
https://www.insideevsforum.com/community/index.php?threads/blue-ev-bar-missing-when-car-is-in-ev-mode.4282/

 

Yup - figured this out recently. Using the paddles right away with a full battery will trigger ICE and no way out of it unless you restart the car.

The blue indicator is gone - the car does go into EV mode after a few miles but mostly behaves like HV. As soon as you start moving, ICE kicks in. In any case, the blue indicator never comes back (different than when in HV mode). Putting the car in HV mode brings the blue indicator back, but going out of HV mode, line goes back to all white.

I posted a thread about this not too long ago. After 13 miles or 25 minutes of driving and getting home, it never fixed itself.

 

Correct - with fully charged.

 

It seems like we’re all driving different cars. I charge fully, just plug it in and let it go. My driveway is downhill, about a 60’ drop over 600’. Then there’s a steep 1/2 mile down hill in either direction. I’ll pull the paddle once or twice to get 2-3 chevrons in order to control downhill speed, then apply light brake pressure for a sharp right turn near the bottom in one of the directions. Have yet to trigger the ICE. The wife took the car today. She’s usually a bit more aggressive on the throttle and brakes than I am. She didn’t trigger the ICE.

In HV, the ICE never “always” stays on. It turns off frequently. At high speeds, when slowing, when stopped. I can always switch from EV to HV to HV Charge, and back to any of the previous selections. Maybe my car is weird? If I experienced some of the described behavior, I’d take the car to the dealer.