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Unusual Or Usual Hybrid Behavior

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In August of 2005, I bought my wife an RX400h and by the time I bought myself an HS 250h in late December 2009, I figured I was pretty experienced at hybrid cars. So imagine my surprise to discover my car behaves quite a bit differently than my wife's in regards to turn on/off the electric motor and gas engine (hybrid system). My question is, has anyone else noticed strange behavior? How does your car behave.

Here are some of my observations:

1. Any time my car has been turned off, when I turn it back on, the gas engine will always turn on. More than that, the longer the car has sat in "off", the longer the gas engine will run. Here is the best example: in the morning, when I turn on my car to go to work, the gas engine will run for four to five minutes, even if I'm coasting downhill. By comparison, my wife's 400h will coast out of the garage in electric-only mode and won't turn on the gas until she either accelerates or hits a hill.

2. Just to further prove that last point, if I do a lot of short trips, I get terribel mileage. A typical example is to drive from my office 1/2 mile to the post office, stop for 15 minutes, then go to the bank and stop for 30 minutes, then go to lunch and stop for an hour, then go to an appointment and stop for 30 minutes. Each time I restart the car, the gas engine runs for a minute or two, with poor mileage. On a day such as I just described, I will actually average under 20 mpg.

By comparison, if I drive those exact same roads *without* turning off the engine, then the gas engine will only run a few minutes in the beginning and after that it's mostly electric. The result is an average of 39 mpg or so. My best days for mileage are when all my stops are at least 5 miles apart.

3. And just to expand further upon the same point: because the gas engine *always* runs when I first turn on the car, that means I cannot turn on the EV mode when I first turn on the car. Only after the gas engine is "done" will the car let me run EV mode. Pratically speaking, that means that if I spend a few hours inside a mall and come out to the parking lot, I cannot use EV mode to drive around the parking lot, even though I'm going 5 mph.

4. This morning I sat in my car for five minutes in my driveway while making a call. Naturally, the gas engine insisted on running the whole time. What I found strange was that the engine surged for about 15 seconds at one point, for no good reason at all.

5. On the way to my home is a small but steep hill. I have to push the car pretty hard to go up the hill but then I coast down the other side. What I've noticed is that most of the time (but not always), when I coast down the back side of the hill, the gas engine continues to run, giving me lower mileage.

6. Generally speaking, I've noticed a number of times when the gas engine will stay on even though I am coasting. At first I thought this was to recharge the battery, but I checked the battery charge and it was 80% full.

7. Speaking of battery charges, mine rarely goes below 50%. Most of the time it's 50-80%. I've only seen it down to 30% a few times.

In spite of all these complaints, I will say my overall mileage is pretty decent. I get about 35-36 mpg on the freeway and 38-40 mpg in the city. And I know that this is all computer controlled, so the question is, what the heck is that computer doing?

Any comments or observations about your own cars would be greatly appreciated.

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I've owned a Civic Hybrid for about 6 years before getting my HS. Here are some of my thoughts based on my experiences with both systems. Keep in mind that the Civic hybrid system doesn't allow for EV mode and only uses the battery to supplement acceleration, kill the engine when in idle, and recharge through coasting or regenerative braking.

1/2/3 - This is normal in my experience. The engine needs to warm up before the computer will allow it to turn off and drive in EV only mode. I'm not sure where you are, but since you posted this in February, I assume that the car's engine is cold when you start it in the morning or after a few hours of not driving. I encourage you to read your owner's manual about EV mode. There are a number of restrictions and the car is smart enough to know when to kill the gas engine and when not to.

4 - I've had this happen in my HS as well. I've found that you can kill the car's power and transfer the call to your handset without dropping the call.

5/6 - This will either be based on your speed or the external temperature.

7 - This is normal and depends on how you drive the car. If you go for extended periods of uphill driving then the battery will get lower than if you engage in "normal" or mixed city/highway driving.

All in all, it seems that your driving experience is pretty standard. If you still have concerns, you should talk to your Lexus dealer... they'll be able to check out your car to make sure that everything is operating as designed.

Take care,

-John

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In August of 2005, I bought my wife an RX400h and by the time I bought myself an HS 250h in late December 2009, I figured I was pretty experienced at hybrid cars. So imagine my surprise to discover my car behaves quite a bit differently than my wife's in regards to turn on/off the electric motor and gas engine (hybrid system). My question is, has anyone else noticed strange behavior? How does your car behave.

Here are some of my observations:

1. Any time my car has been turned off, when I turn it back on, the gas engine will always turn on. More than that, the longer the car has sat in "off", the longer the gas engine will run. Here is the best example: in the morning, when I turn on my car to go to work, the gas engine will run for four to five minutes, even if I'm coasting downhill. By comparison, my wife's 400h will coast out of the garage in electric-only mode and won't turn on the gas until she either accelerates or hits a hill.

2. Just to further prove that last point, if I do a lot of short trips, I get terribel mileage. A typical example is to drive from my office 1/2 mile to the post office, stop for 15 minutes, then go to the bank and stop for 30 minutes, then go to lunch and stop for an hour, then go to an appointment and stop for 30 minutes. Each time I restart the car, the gas engine runs for a minute or two, with poor mileage. On a day such as I just described, I will actually average under 20 mpg.

By comparison, if I drive those exact same roads *without* turning off the engine, then the gas engine will only run a few minutes in the beginning and after that it's mostly electric. The result is an average of 39 mpg or so. My best days for mileage are when all my stops are at least 5 miles apart.

3. And just to expand further upon the same point: because the gas engine *always* runs when I first turn on the car, that means I cannot turn on the EV mode when I first turn on the car. Only after the gas engine is "done" will the car let me run EV mode. Pratically speaking, that means that if I spend a few hours inside a mall and come out to the parking lot, I cannot use EV mode to drive around the parking lot, even though I'm going 5 mph.

4. This morning I sat in my car for five minutes in my driveway while making a call. Naturally, the gas engine insisted on running the whole time. What I found strange was that the engine surged for about 15 seconds at one point, for no good reason at all.

5. On the way to my home is a small but steep hill. I have to push the car pretty hard to go up the hill but then I coast down the other side. What I've noticed is that most of the time (but not always), when I coast down the back side of the hill, the gas engine continues to run, giving me lower mileage.

6. Generally speaking, I've noticed a number of times when the gas engine will stay on even though I am coasting. At first I thought this was to recharge the battery, but I checked the battery charge and it was 80% full.

7. Speaking of battery charges, mine rarely goes below 50%. Most of the time it's 50-80%. I've only seen it down to 30% a few times.

In spite of all these complaints, I will say my overall mileage is pretty decent. I get about 35-36 mpg on the freeway and 38-40 mpg in the city. And I know that this is all computer controlled, so the question is, what the heck is that computer doing?

Any comments or observations about your own cars would be greatly appreciated.

I have noticed the same thing on my HS. Can you tell me where you read out the level of battery charge?

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