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Discussion Starter #1
I've had my Prius for 1 week & 1 day now. Overall, I am pretty happy. One question for you guys: do you find your energy monitor to be inaccurate at times? Specifically, mine will show that nothing is being used (no electric or ICE use) but I can clearly hear the ICE. Usually the ICE use will be displayed moments later. Is this normal or should I have them look at it?

Thanks,
sam
 

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So you're saying at times there may be a ~3 second delay in some situations? I'm comparing this to the usual simutaneous update. Example is when you start the engine in EV mode and seconds later the ICE kicks on and how the display is instantly updated.
 

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There is a short but noticeable and significant delay between any change in status, and the display of the change on the MFD. The display always lags the actual power flow state.

In addition, the power flow shows (you guessed it!) the flow of power. If the engine is in the warm-up phase there may be times when it is running but there is no load on it (the electric motors are supplying the power -- or at a stop it can be running without supplying any power to MG1 for charging). Under this special circumstance, you may hear the ICE running but see no energy flowing from it on the display.
 

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You can also see the affect Daniel mentioned if you are moving forware, the ICE is running, but all your power is coming from the electric motor. Your MPG will not read 99.9, but something else (for me it's anywere between 10 and 90MPH, depending on my speed).

Most of the time this happens is when the engine is not hot yet. But I've had it happen are rare ocasions when the engine is hot (like this morning when I got to work). It may be that the 12 volt battery needed charging???
 

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CaPriusLover said:
It may be that the 12 volt battery needed charging???
The Prius has no alternator. The 12-v battery is charged by an inverter from the HV battery.
 

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Daniel said:
CaPriusLover said:
It may be that the 12 volt battery needed charging???
The Prius has no alternator. The 12-v battery is charged by an inverter from the HV battery.
Humm, any thoughts as to why my ICE is running when my battery charge level is green and I'm drinve 10 MPH in a parking lot (after coasting into it)? I had already traveled 27 miles, so the motor was hot. I tried to "feather" the thing, but that didn't work either.
 

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If the engine had started to cool from being off for a while during a long coast or regen then it will restart to re-warm itself up to it's set-point. This happens to me sometimes when I coast in for the last 1.5 miles approaching my house and again as I coast and crawl on the freeway as I approach my job.
 

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CaPriusLover said:
Humm, any thoughts as to why my ICE is running when my battery charge level is green and I'm drinve 10 MPH in a parking lot (after coasting into it)? I had already traveled 27 miles, so the motor was hot. I tried to "feather" the thing, but that didn't work either.
Today my ICE did something unusual. As I sat at a stop sign waiting for a chance to cross the intersection the ICE shut down and then immediately started back up. It ran for a couple of seconds, then shut down again, ran for a couple more seconds and shut down, started up again and shut down again; it cycled like this six or seven times! I was perplexed, so I switched to my LCD from "consumption" to "energy" and saw that my battery was completely full and it appeared that the ICE was being used to dump excess regenerated electricity. Perhaps this was what your ICE was doing.
Drive happy,
Moo :)
 

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CaPriusLover said:
That could be the case. When you say your battery was completely full, are you saying all 8 bars??? I've never see more than 7.
Yeah, green bars all the way to the top. I'm not sure why this happened as I was simply driving around town. The only other time I've been aware of my battery "topping off" was coming down a long mountain pass. Normally my battery reads a couple of bars below full.
drive happy,
Moo :)
 

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moocatdog said:
it appeared that the ICE was being used to dump excess regenerated electricity.
Odd behavior... "the battery's full, so let's burn some fuel while we try to reduce the battery charge". I would think it would just go battery-only for awhile and let initial accelleration, etc. take it down, but I didn't program it. 8)
 

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TechnoMage said:
I would think it would just go battery-only for awhile and let initial accelleration, etc. take it down, but I didn't program it.
Me neither, so (as Frank Zappa said) I could be totally wrong. :)

Drive happy,
Moo :)
 

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That battery-dumping behavior has been reported elsewhere, also.

CaPriusLover said:
Humm, any thoughts as to why my ICE is running when my battery charge level is green and I'm drinve 10 MPH in a parking lot (after coasting into it)? I had already traveled 27 miles, so the motor was hot. I tried to "feather" the thing, but that didn't work either.
It will not run on battery-only in stage 3a operation. You need to come to a full stop (after the engine is fully warm) and wait the 5 or 10 seconds it take for the ICE to stop. After that you are in S4 and the car will run on electric. Until then, it will not.

If, after the ICE is fully warm, but before you have had a 5 or 10 second stop, you exceed a certain threshhold speed (somewhere around 35 mph) you will go into stage 3b operation. In this mode, the car will run on electric only if conditions warrant it. But once you slow down below the threshhold speed and apply the brakes, you will be back in S3a, and the car will not run on electric only.

None of this makes any sense, but it is the observed behavior of the car.

The situation you describe (quoted above) is one of the situations when the EV switch is useful. I believe that driving at a slow speed with a nearly-full battery is inefficient. The EV switch will shut the ICE off even though you are in S3a operation. (Not sure about S2.) The next time this happens, you might want to glance at your instantaneous mpg. If it's up around 60 you have no problem. If it's down around 12 or 15 you want to use your EV switch if you have one. I always use my EV switch in parking lots.
 

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Thanks for the infor Daniel. Now I REALY can't wait for my EV switch to arrive!

Just to clear things up a little, here is my normal routine when I exit the freeway:
1. about 1/2 mile from the end of the offramd, turn off CC and coast.
2. Stop at end of offramp
3. Excellerate to about 30 MPH and hold speed through 1 traffic light.
4. Halfway to next light, coast (will be turning right at light)
5. Make right turn, still coasting.
6. Apply very little throttle (will show 99.9 MPG in energy monitor).
7. About 50 yards from right turn is the driveway I turn into. Coast into this driveway (only doing between 15 - 17 mpg at the begining of the turn)
8. Apply lite pressure to accellerator (sp?) and drive to parking spot.

19 times out of 20, I'm electric in the driveway. It's that 1 time out of 20 that I'm not that eats me up! The MPG reading is normally between 60 and 90, but the monitor shows all electric which means my ICE is running.

Anyway, my EV switch will put an end to THAT problem! :)
 

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CaPriusLover said:
Thanks for the infor Daniel. Now I REALY can't wait for my EV switch to arrive!

Just to clear things up a little, here is my normal routine when I exit the freeway:
1. about 1/2 mile from the end of the offramd, turn off CC and coast.
2. Stop at end of offramp
3. Excellerate to about 30 MPH and hold speed through 1 traffic light.
4. Halfway to next light, coast (will be turning right at light)
5. Make right turn, still coasting.
6. Apply very little throttle (will show 99.9 MPG in energy monitor).
7. About 50 yards from right turn is the driveway I turn into. Coast into this driveway (only doing between 15 - 17 mpg at the begining of the turn)
8. Apply lite pressure to accellerator (sp?) and drive to parking spot.

19 times out of 20, I'm electric in the driveway. It's that 1 time out of 20 that I'm not that eats me up! The MPG reading is normally between 60 and 90, but the monitor shows all electric which means my ICE is running.

Anyway, my EV switch will put an end to THAT problem! :)
Okay. I'm baffled. That behavior should not appear except in Stage 1 (warm-up) where the ICE is running but not providing power to move the car.

If the ICE is running, you should see power arrows coming out of it once it's warmed up. And if you see the arrows showing all power coming from the battery, and the car is not in Stage 1 operation, then your mpg should show 99.9

I have had the car sometimes refuse to go into golf-cart mode at slow speeds, but in those cases it always shows arrows leaving the engine. Also, in those cases the mpg is very low. If you are seeing over 60 mpg, then your efficiency is fine and there's no need for EV mode (unless you just want to impress the on-lookers with the silence of your car).

I'm completely baffled.
 
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