ICE runs after going down a hill at the beginning of my drive.

The Leaf we had would gain range, but not bars in the gauge. Mostly, ICE comes online when the battery is full, but it has come on when not full. But full is relative. How can the battery be full when the car has been drive nearly a mile? The battery has to be depleted at least somewhat. ICE has never come on when the battery has lost a couple of bars.

 

I wrote to Dan Neil who writes for the WSJ.

Hello Dan,
Have you reviewed the Honda Clarity Hybrid? We are leasing one, and have an issue with its “performance.” In the InsideEVs forum for the Clarity, several of us have noted that the ICE will suddenly come online for no apparent reason. Battery is full. I expected that the car would run in EV mode until the battery is depleted, or when the user chooses to bring it online by choosing HV mode or “tromping” on the accelerator. I have brought the car to 2 dealers. They find nothing wrong. Honda is not interested in investigating or fixing the issue.

hey Robert, Well, the control systems that fire up the ICE have their own reasons (hp needed, a/c demands, keeping the engine to temp....). But I had a similar feeling when I was driving the T8 Volvo V60. I couldn't keep the thing in battery mode. If it's any consolation, the Clarity is probably running super-clean anyway.

 

bobcubsfan: You say "but it has come on when not full" and then "ICE has never come on when the battery has lost a couple of bars". Is this contradictory info? Or maybe I misunderstood? I think you mean that it comes on when "all bars" or "all bars minus 1" or "all bars minus 2" is your battery charge state. Does it start only when you are going downhill? Or maybe only when you step off the gas pedal? Did it ever come on when you are in EV mode and gently pressing the gas pedal? Sorry for lots of questions, I just try to understand the situation.

If I go the other way from my home, there is another steep down hill about half a mile away. Mine does not come on there, since (I'm assuming) I already spent half a mile worth of charge. But of course all the bars are still there at 0.5 miles away.

 

The behavior is erratic. Mostly, ICE comes online after driving for less than 1 mile. Curiously that means that the battery cannot be fully charged at that point. Once in a while, ICE will come online several times during a drive. Obviously the battery cannot be fully charged then. Sometimes, like today, ICE did not come online at all. Same driving conditions.

 

HV Charge will only charge the battery to 58% per Honda. So I suppose you've discovered what happens when you get the battery up to 58%: the system switches to default mode (EV). I would have expected it to only switch to HV mode at that point. Or are you saying that regenerative braking would no longer work after self-charging to 58%?

 

Cannot see the point of using the ICE to charge the battery.

 

I acknowledge that you'll never see the point.

 

Bob...save yourself from all of this....break your lease and buy a Nissan Leaf....LOL

 

No. The Clarity is a much better car than the Leaf. Roomier, bigger trunk.

 

As a 5.5 year Nissan Leaf owner, I will not recommend anyone buying Leaf until they have liquid cooling, maybe except for people living around the South Pole. It is rumored that it will have it in 2019.

I feel terribly sorry for the people who spend $30-35K on Leaf in Texas, Arizona, Florida.

 

I agree about the Leaf. We are in Southern California. It gets pretty hot here in summer. The new Leaf has some improvements over the older model. Range, cruise control, one pedal braking, etc. But the interior is much the same.

 

I’ve seen regen causing the ice to come on with a much as 5 miles driven, if I turn on 4 chevrons of regen. So now I avoid regen the first few miles and then gradually increase the chevrons. Maybe this could be the solution for you too?

 

In the Volt this is called Mountain Mode.

If you’re in the mountains you might need to if you have a long steep climb coming up. You’ll want enough battery range to help climb, so the 1.5 liter engine doesn’t struggle as much. Of course, you should HV charge before the climb, not during lol

 

In Econ EV mode. No chevrons. One time I did force ICE as you described.

 

Regenerative braking works fine. It's the parallel hybrid charging at part throttle that won't work once the battery is at about 35 mile EV range. That's a bit more than 58% so I wasn't sure if that's a known mode. I'll have to look at the chart with the various scenarios to see whether it's depicted.

 

Can someone with this situation try it with the instant fuel economy display?

I’ve seen zero consumption going down steep hills where the engine was running in HV mode. Motor on, gear icon was off so I was thinking maybe the hill was beyond the regen range and the extra current was feeding the second motor to spin the engine without fuel (or a very small amount).

 

Bob,
Every Clarity has exactly the same software so there are only 2 variables that could make an individual car behave uniquely; sensors and the battery. A faulty sensor would throw a code so this is easy to check. A defective battery may not code but, given that it holds a charge in a manner that, from owner description, is identical with every other Clarity, this seems very unlikely.

I'd suggest you ask your Honda dealer to lend you a demo car for a weekend and see if it behaves differently. I strongly believe it won't but you never know. Just bear in mind the software controlling these cars is massively complex with many choices/compromises made by the software engineers.

 

I tested my Clarity yesterday. We have a 0.3 mile very steep downhill at the exit of our driveway. After topping up the battery, I immediately drove down there, with full regen (regen at 4th level). I saw the green power flowing to the battery all the way down. The engine never came on. It might be because 0.3 mile is too short to test?

The engine has not started in the last 2.5 weeks since we drove from Houston from Austin.

 

A technical suggestion:

Last winter when the temperature was below 50F, we found the Prius Prime would unexpected run the engine. But it was puzzling until we started making videos to document the displays showing when and where it was occurring. We were able to 'reverse engineer' some previously undocumented engine ON conditions and workarounds to avoid them. For example, there was a speed threshold, 40 mph, that with SOC in the 90-100% range, the engine would come ON for at least 3 minutes. But if you came to a stop, power cycled the car, it would put it back in EV mode with the engine OFF. By then the SOC was typically under 90%.

You might consider getting a ScanGauge II to monitor some basic engine metrics. Things like mass flow, RPM, temperatures, and injector timing can provide a lot of insights. For example, some Prius owners claimed the engine would spin without burning gas but metrics showed gas was burned to keep the exhaust hot enough so the catalytic converter kept working. One reported problem with diesels (in the past) was idling in stop and go traffic, the exhaust would chill the NOx converter and it would reduce or stop working until heated.

GOOD LUCK!
Bob Wilson

 

I did a series of tests that I wrote up on the forum last month with a similar situation. I topped off my charge with the Clarity literally sitting on the hill and I was able to get the regen to come on. However, with the normal drive out of my driveway the regen never comes on.

It seems to be a razors edge of using just enough charge to then "absorb" the regen.

BTW If for some perverse reason you want to suffer through the details of my experiments they are here:

https://insideevsforum.com/community/index.php?threads/ice-re-generation-and-the-big-hill-a-novella-in-three-acts.2243/

geo