Car running on ice/gas despite full battery

Maybe system check up? It stated in the manual that occasionally the ICE will turn on at the beginning of the startup for system check until it reach working temp

 

One could be a System Check but it’s improbable to have two System Checks that close together. One or more sounds like the full charge with limited regen to protect battery by using he ICE (in a way that we don’t understand yet) from over charge scenario discussed at length in other threads.
Note that the ICE will run until it reaches normal operating temp whenever it is started for any reason. It best to just let it run it’s brief course as trying to make it stop may cause it to run again to complete whatever cycle the computer had called it up for.
Try braking gently the first 3-4 miles and see if that helps. Also try to notice that at the beginning of a drive immediately after a full charge that regen is limited-it won’t go as far down into the green as it usually does and pedal braking will not add more or nearly as much regen as usual. If you can get by this short period, the ICE is much less likely to run on the rest of the trip.
Let us know if that helps any.

 

Scenario 2: Going 25 mph to freeway speed in sport mode , ICE runs for 8 miles

When I read this, my first thought was that (especially if up an incline) the ICE iis coming on to supplement battery power during rapid acceleration. Especially if you “punch it” a little bit. Then, as it always does, once called upon it runs for about five minutes.

Any thoughts about whether, when you accelerate up to freeway speed, you’re getting anywhere near the white bar on the power meter? My experience is that even if it gets to that white/blue hatched area the ICE will come on in this scenario.

I drive in NORM not SPORT to take the edge off my tendency to do this

 

Be aware that the engine will kick in depending on how far you press the accelerator and where that happens is sooner depending on what mode you are in. On the below pic (from the manual) that dotted dashed line represents the end of the blue arc, so in sport you will trigger the engine just past half way on that blue line -- which takes a lot of babying and defeats the reason to be in sport mode.

Basically if you want the EV to stay on as much as possible, stay in econ EV mode only.

 

Very true. I'm always always in econ but one day I was playing with the modes and went to normal. I made a right turn against a red so I needed to accelerate a bit more than normal. The ICE came right on long before the click point and the acceleration was swift. It did stay on for quite some time though, presumably to fully warm up. That part I didn't like so I stay in Econ mode nearly always now. Our town is fully of friendly drivers so there's more than plenty of acceleration there for everyday driving.

 

I think that if the ICE turns on just let it run it’s course. If you force it off, that could be why it turns on in an unexpected time later as its trying to finish what it started earlier.

 

The dashed line represents where the pedal detent is, not where the end of the blue arc is. All the mode buttons do is change the mapping of the accelerator. In Sport mode, very little movement is needed to get much farther up into the blue. But, the ICE won't come on until you hit the end of the blue regardless of what mode you're in. It's only the pedal response that is changed by the mode buttons.

 

Thanks. I've yet to "floor" it personally.

 

Mine did this for about 15 min the other night, when battery was about 75%

 

Methinks this should be a topic for the FAQ. Basically if you fill the battery to 100% and immediately go down a hill and do the region paddles, the engine will turn on for about 10 minutes.

Possibly using the brakes will work better during the first few minutes of operation of the car since the car may be smart enough to just use friction and not regain if the battery is already full.

Also mention the theory that it may not be the best idea to constantly charge to 100%. While the car computer most likely will prevent the battery itself ever reaching a true 100%, the margin it allows is not large enough to make some comfortable about it.

 

The car should regularly be charged to 100% to make sure cell balancing occurs. You don't have to every time, but your SoC meter will likely wander and if your cells become unbalanced you could have a suddenly dead battery. In the Clarity 100% appears to be about 85% max SoC if 4.05 volts per cell is fully charged.

 

Um, Scangauge data says 100% HL App SOC equates to 96% Actual: https://insideevsforum.com/community/index.php?threads/scangauge-ii-extended-pids-capacity-and-specific-energy.2633/#post-24188

No?

 

Doesn't match what 4.05 volts for an NMC cell charge curve should be with Vmax of 4.2 volts. It might mean something else or maybe ScanGauge calculation needs calibration/adjustment. I took the 4.05 volts from that thread as the fully charged voltage so I am assuming that is correct.

 

4.05 is a safe cell charged voltage for NMC. It means it was charged to about 85% according to charge curves in studies I have seen, however under discharge that voltage should drop due to internal resistance so might show lower than 4.05 volts if you read the voltage while discharging. It appears ScanGauge might be using the discharge curve to calculate SoC when static, this might give higher SoC reading. My point is it probably doesn't matter what ScanGauge is showing there, the static voltage seems to show that Honda runs the battery in a safe range for NMC, similar to very reliable Volt battery.

 

So the disagreement here is whether 4.05 or 4.19 V is absolute max SOC for NMC?

 

No, 4.2 is max charge, 4.05 is what charging stops at according to that thread.

 

Yes, charging stops at 4.05, which equates to 96% of MAX, not 85%.

 

I believe there is still room to wonder what is really going on. The 4.05 Volt compared to the published Chinese NMC battery SOC curves would indicate a range between 85% to 95% depending upon what voltage is actually being measured, and for the Korean LG-Chem battery it was about 5% lower. So clearly battery chemistry is important here. Then there is the uncertainty over exactly what the OBD-II values are. So far, from reading ScanGauge we have:
SOC - State of Charge
MXS - Battery Cell Max State of Charge

Now, the Honda engineers were free to decide how they were going to interpret what each of those parameters indicates and we don't have the Honda explanation. I know from my own experience that when you ask several engineers to implement a "spec" you are likely to get several different implementations At this time, we need to keep gathering data to see if we can reverse engineer the meaning of it all.

 

No, according to studies I posted in that thread 4.05 V is between 80 - 90% for NMC for charging. If you measure voltage with no load and it shows 4.05 V SoC is about 85%. It is not linear, you can't do 4.05/4.2