Clarity Issues

[David Towle]

The single-speed transmission is in effect only when you're cruising above about 45 mph in HV Mode, when the Clarity's clutch can (at the computer's discretion in the interest of efficiency) connect the output of the engine to the gears driving the wheels (Engine Drive mode). Most of the time, the i-MMD system is performing as an eCVT, where the battery along with the engine driving the starter motor/generator provide exactly the amount of power for your driving needs. Because the engine speed is not directly proportional to the road speed when not in Engine Drive mode, the collection of mechanisms Honda calls an eCVT performs much like a conventional CVT.

Insightman are there any drawings that show how this works? I think what you are saying is above 45 mph there is a direct single speed connection, and below that the engine/generator can bypass the battery and send power directly to the electric motor. What this means then is there is actually LESS than 103 hp available below 45 mph as generator/motor arrangements usually have more losses than mechanical connections, so probably 90 hp or so. And above 45 mph its unlikely the engine is operating at its power peak, so there we are also somewhere under the 103 hp.

So with a 4100 pound car it sounds like the best thing to do if you run out of battery is pull over in long push HV mode and give it a half hour to charge the battery.

 

[PHEV Newbie]

Insightman are there any drawings that show how this works? I think what you are saying is above 45 mph there is a direct single speed connection, and below that the engine/generator can bypass the battery and send power directly to the electric motor. What this means then is there is actually LESS than 103 hp available below 45 mph as generator/motor arrangements usually have more losses than mechanical connections, so probably 90 hp or so. And above 45 mph its unlikely the engine is operating at its power peak, so there we are also somewhere under the 103 hp.

So with a 4100 pound car it sounds like the best thing to do if you run out of battery is pull over in long push HV mode and give it a half hour to charge the battery.

Thank you everyone. There was a period when the advice on this forum was to drive in EV, deplete the battery, and let it shift over to hybrid mode. I believe that it's clear now that you should avoid doing that, always. If the car was meant to do that, Honda would have installed a bigger 2.0 litre ICE, at least. That's what they put into the Accord Hybrid with the same two electric motor drive system and it weighs nearly 700 lbs less than the Clarity. Folks, the Clarity's little 1.5 litre ICE puts out 103 hp, but that's at the crankshaft, not at the wheels. The ICE must spin to generate electricity to drive the traction motor, losing energy at each step. From the battery only, the Clarity puts out 121 hp. Combining a fully charged battery + ICE generator only adds 60 hp to 181 hp maximum so with a depleted battery, you might be driving a 2-ton car with less horsepower than a two-seater Smart mini-car (89 hp) and those are slow! My advice is to never let the battery dip below 50% if you know you'll need to drive in HV mode before your next charge. I for one, would like to know that all 212 horses are available to me than to limp along on 60 or so horsepower.

 

[Breezy]

Horn responsiveness
The main issue we've had to date (had the car since early Sept) is the way-too-stiff horn control. It takes more pressure than it should in an emergency situation to beep the horn. I've had two close calls to date where my first attempts to blow the horn to avoid collision didn't work and the (fraction of) second needed to redo the action might have meant an accident. Thankfully didn't. Still, the horn mechanism is not well engineered. Anyone know of a fix? There's a thread to replace the horn with louder ones, but at this point I just want a more responsive horn!

 

[Michael Borquez]

Insightman are there any drawings that show how this works? I think what you are saying is above 45 mph there is a direct single speed connection, and below that the engine/generator can bypass the battery and send power directly to the electric motor. What this means then is there is actually LESS than 103 hp available below 45 mph as generator/motor arrangements usually have more losses than mechanical connections, so probably 90 hp or so. And above 45 mph its unlikely the engine is operating at its power peak, so there we are also somewhere under the 103 hp.

So with a 4100 pound car it sounds like the best thing to do if you run out of battery is pull over in long push HV mode and give it a half hour to charge the battery.

So from what I’ve been able to gather, there is a clutch that engages the engine to drive gear at highway speeds. It appears there is a small electronically controlled CVT between the engine and drive gear. It’s not like a traditional CVT and only changes the ratio slightly to not put such a heavy load on the engine. I’m still searching for schematic, but this would explain the angry bees issue. I believe that since it is electronically controlled the angry bees issue can be resolved with software to be more proactive before the car reaches the too depleted to operate efficiently stage.

 

[Louis Nisenbaum]

Driving in town less than 50 miles, I use all electric. If we’re going on a trip, I use hybrid mode and drive until I Get close to my destination and then use the rest of the electric power. I don’t think this is this is that complicated. Smooth and plenty of power and got 45 mpg driving on a 450 mile trip.

 

[PHEV Newbie]

Driving in town less than 50 miles, I use all electric. If we’re going on a trip, I use hybrid mode and drive until I Get close to my destination and then use the rest of the electric power. I don’t think this is this is that complicated. Smooth and plenty of power and got 45 mpg driving on a 450 mile trip.

That's the right way to do it. For safety sake, you should always avoid driving on a depleted battery.

 

[David Towle]

Thank you everyone. There was a period when the advice on this forum was to drive in EV, deplete the battery, and let it shift over to hybrid mode. I believe that it's clear now that you should avoid doing that, always. If the car was meant to do that, Honda would have installed a bigger 2.0 litre ICE, at least. That's what they put into the Accord Hybrid with the same two electric motor drive system and it weighs nearly 700 lbs less than the Clarity. Folks, the Clarity's little 1.5 litre ICE puts out 103 hp, but that's at the crankshaft, not at the wheels. The ICE must spin to generate electricity to drive the traction motor, losing energy at each step. From the battery only, the Clarity puts out 121 hp. Combining a fully charged battery + ICE generator only adds 60 hp to 181 hp maximum so with a depleted battery, you might be driving a 2-ton car with less horsepower than a two-seater Smart mini-car (89 hp) and those are slow! My advice is to never let the battery dip below 50% if you know you'll need to drive in HV mode before your next charge. I for one, would like to know that all 212 horses are available to me than to limp along on 60 or so horsepower.

I think it depends a lot on where you drive, its not necessary "always". If you're in a flat area the 2 battery bars remaining should always be plenty to get you up to speed with a reserve. If you live in the hills that won't be enough. A nice software feature would allow you to dial in the minimum battery level before EV switches to hybrid that matches your local situation.

 

[KentuckyKen]

I purposely let the battery deplete to 0 EV (2 bars) and automatically enter “HV” mode as an experiment. With no hills to speak of, I had a normal driving experience with plenty of power in city driving and on highway at 50 mph. I would not want to try it on the Interstate at 70+ mph or with any hills, but locally it was fine in the flats. I always use HV mode with a nearly full battery for long trips. And BTW, I’ve never heard the angry bees even on steep hills. As previously said, it pays to drive HV with a significant charge.

 

[insightman]

Insightman are there any drawings that show how this works? I think what you are saying is above 45 mph there is a direct single speed connection, and below that the engine/generator can bypass the battery and send power directly to the electric motor. What this means then is there is actually LESS than 103 hp available below 45 mph as generator/motor arrangements usually have more losses than mechanical connections, so probably 90 hp or so. And above 45 mph its unlikely the engine is operating at its power peak, so there we are also somewhere under the 103 hp.

So with a 4100 pound car it sounds like the best thing to do if you run out of battery is pull over in long push HV mode and give it a half hour to charge the battery.

See my post (and the post after that one) about the presentation I put together for a plug-in car event. Many on this forum helped me with constructive criticism and suggestions.

 

[David Towle]

Wow that is great, thanks. Is there anything available on how the climate control system works, when it selects resistance vs heat pump etc?

 

[KentuckyKen]

Wow that is great, thanks. Is there anything available on how the climate control system works, when it selects resistance vs heat pump etc?

Based on several posts and diagrams shared by our helpful owners who have paid for a peak at Honda Tech, the PHEV Clarity does not have a heat pump, just ac for cooling and resistance heat via coolant loop and heater core with ability to use engine heat at times.

 

[Zor]

Thank you everyone. There was a period when the advice on this forum was to drive in EV, deplete the battery, and let it shift over to hybrid mode. I believe that it's clear now that you should avoid doing that, always. If the car was meant to do that, Honda would have installed a bigger 2.0 litre ICE, at least. That's what they put into the Accord Hybrid with the same two electric motor drive system and it weighs nearly 700 lbs less than the Clarity. Folks, the Clarity's little 1.5 litre ICE puts out 103 hp, but that's at the crankshaft, not at the wheels. The ICE must spin to generate electricity to drive the traction motor, losing energy at each step. From the battery only, the Clarity puts out 121 hp. Combining a fully charged battery + ICE generator only adds 60 hp to 181 hp maximum so with a depleted battery, you might be driving a 2-ton car with less horsepower than a two-seater Smart mini-car (89 hp) and those are slow! My advice is to never let the battery dip below 50% if you know you'll need to drive in HV mode before your next charge. I for one, would like to know that all 212 horses are available to me than to limp along on 60 or so horsepower.

This really isn't quite right. It would be if there was not a battery in the car. The depleted hybrid mode should have its own percent of power assigned to it. If you haven't noticed the engine rev is not fully connected to the acceleration and can and will continue beyond your acceleration. This is the system negating your power issue. However there is a bug in it. It doesn't seem to fully regain the lost buffer in some situations. When that buffer hits zero, you have power output issues. It also could be that this buffer is not big enough for all situations as well. The engine output has be greater then the motor output for it to regain that lost charge. That may not be the case in mountain climbs.

 

[amy2421]

I purposely let the battery deplete to 0 EV (2 bars) and automatically enter “HV” mode as an experiment. With no hills to speak of, I had a normal driving experience with plenty of power in city driving and on highway at 50 mph. I would not want to try it on the Interstate at 70+ mph or with any hills, but locally it was fine in the flats. I always use HV mode with a nearly full battery for long trips. And BTW, I’ve never heard the angry bees even on steep hills. As previously said, it pays to drive HV with a significant charge.

My experience with 0 EV range was that the car switched on the ICE, did not display "HV" on the dash (although it does if I press the HV button) and the power is OK but it feels rougher somehow and the ICE engine is unpleasantly noisy. Less noisy on flat roads than on an uphill. I don't know if this is fact or just my imagination, but it seemed to feel marginally smoother when I pressed the HV button after the ICE came on with 0 EV range.

 

[insightman]

My experience with 0 EV range was that the car switched on the ICE, did not display "HV" on the dash (although it does if I press the HV button) and the power is OK but it feels rougher somehow and the ICE engine is unpleasantly noisy. Less noisy on flat roads than on an uphill. I don't know if this is fact or just my imagination, but it seemed to feel marginally smoother when I pressed the HV button after the ICE came on with 0 EV range.

Can you speculate on what your Clarity is doing differently when you press the HV button with zero EV range? It would seem to me that when the battery is exhausted, the Clarity has no option but to run the engine as hard as necessary to respond to the accelerator pedal. If the engine icon turns off when you switch to HV Mode, perhaps you've driven far enough to build up a charge that can give the engine a break?

 

[David Towle]

Based on several posts and diagrams shared by our helpful owners who have paid for a peak at Honda Tech, the PHEV Clarity does not have a heat pump, just ac for cooling and resistance heat via coolant loop and heater core with ability to use engine heat at times.

Thanks that's helpful. I was wondering that because it was a bit colder yesterday and the range was way down under 35 miles. I need to use HV more. One problem with this, is on my car when I try to switch HV off it doesn't even when there's lots of juice in the battery. The HV indicator goes off, EV indicator doesn't go on, and I still hear the engine and see it on the graph. The only way I got it back on EV was restarting the car.

 

[insightman]

Thanks that's helpful. I was wondering that because it was a bit colder yesterday and the range was way down under 35 miles. I need to use HV more. One problem with this, is on my car when I try to switch HV off it doesn't even when there's lots of juice in the battery. The HV indicator goes off, EV indicator doesn't go on, and I still hear the engine and see it on the graph. The only way I got it back on EV was restarting the car.

Many of us with "engine anxiety" wish there was a way to force the engine to cease and desist without having to stop and restart the car. Honda is mum about how the Clarity PHEV decides when to shut off its engine, but a popular belief is that once the engine starts, it wants to warm itself up before it considers abdicating to the battery. After I heard that, I stopped compulsively looking for a place to pull over and restart. However, by "going with the program," I couldn't get Honda's gas to last more than 10 months.

 

[David Towle]

Many of us with "engine anxiety" wish there was a way to force the engine to cease and desist without having to stop and restart the car. Honda is mum about how the Clarity PHEV decides when to shut off its engine, but a popular belief is that once the engine starts, it wants to warm itself up before it considers abdicating to the battery. After I heard that, I stopped compulsively looking for a place to pull over and restart. However, by "going with the program," I couldn't get Honda's gas to last more than 10 months.

That's too bad. I live in an area where electricity is not cheap, 17 kwh costs about $3.20 and is about equal to a gallon of gas at $2.90. I hate to use the resistance heater to warm the cabin if I could use waste heat from the engine to bring it up to temperature then switch to EV. But it looks like that's not practical.

 

[KentuckyKen]

@insightman, I’m driving all EV and my ICE is only coming on once every 3-4 weeks on its own according to my hour meter (outside of 1 instance of too rapid acceleration and 1 of hard braking right after charging). So far in 6 months I haven’t even lost a bar. The ICE comes on at low rpm and turns off after a few minutes. My best estimate is that it’s burning around 1/10 gal each month. My tank easily will last a year so I added Stabil to the tank.

 

[insightman]

That's too bad. I live in an area where electricity is not cheap, 17 kwh costs about $3.20 and is about equal to a gallon of gas at $2.90. I hate to use the resistance heater to warm the cabin if I could use waste heat from the engine to bring it up to temperature then switch to EV. But it looks like that's not practical.

I have one word for you: Layers. See this post where I describe my unreasonable pursuit of EV range.

 

[Robert_Alabama]

When I am driving all EV, I am experiencing pretty much what KentuckyKen is describing. Maybe a teacup of gas each time the engine runs on it's own, maybe once every couple of weeks. I do occasionally get the engine on with hard acceleration, but again, little gas burn. I drive about 6.5 miles to work , and even if I get the gas engine on for acceleration, the trip computer shows about 150 mpg or about 5 ounces of gasoline. Essentially all the gas I have burned in 6 months has been highway driving. I don't think even a gallon has been burned when I have had battery available over the 5 months I've had the car.