Hi everyone, I'm hoping someone here can help me. I have a 2008 prius (pkg 5) with about 9000 miles. I was in traffic yesterday, coasting at about 5 mph for about an hour. I had to drive onto lawn to park my car, but everything seemed fine up to this point. When I got back into the car to leave, I rolled down my window to ask someone for directions, when I tried to roll it back up it would not go back up. It was at that point I realized I was loosing battery power. I don't know if this was the right thing to do or not, but I put the car in park and floored the gas petal for a few minutes. After a while I was able to roll up the window again. I then proceeded to drive off normally. Today I had no problems at all. Another thing worth mentioning is that I noticed the consumption screen did not have those little green cars on the 5 min yellow bars and the levels were all very very low, maybe at the 5 mpg mark. This was the case for the whole hour while in traffic. The traffic was moving so slowly that I don't even remember accelerating much at all, just letting off the brake and rolling along. Does anyone here know what I did wrong? I always thought that if the battery needs to be recharged that the gas engine would automatically kick in. Is this not correct? Any input would be great. TIA.
Yes, the internal combustion engine turns on ... even at very low speed or sitting stationary, if the traction pack is low. But if you accidentally (or deliberately) had it in neutral, the ICE will NOT turn back on. That may have been what happened, if the ICE never started. Similarly, if the ICE is running and it's in neutral ... she no charge. .
Hmmm, I didn't change to neutral. I was in drive, driving normally when traffic slowed down. How does someone "accidently" go into neutral? Forgive me if I seem ignorant, but I didn't think you could move at all in neutral. Can you elaborate? (I appreciate your answers btw.)
I'd guess that when you parked it you somehow left it in IG-ON or ACC instead of shutting it completely OFF, and were draining one or the other of the batteries. Always lock the car, and if it is not OFF it will give a long beep.
I drive an '08, so I have a vested interest in issues such as this being resolved satisfactorily. Here's my take... I think the genesis of this "condition" was solely due to low HV battery State of Charge, SOC. At very low speeds, that is very low torque requirements, the HSD tends to use the HV battery most if not all of the time. If you were watching the MFD Consumption screen, the one with the fat yellow bars, everything would look fine; 100 MPGs minute after minute. But if you where watching or had switched to the Energy Monitor screen, the one with the colored arrows, you would have seen the SOC slowly dropping into the two-bar red zone. From time to time the ICE would come on and charge the HV battery up to three blue bars. I suspect that you left the highway with three blue bars, a very low SOC. Driving acros the lawn left you with just enough SOC that three blue bars just barely showed and the ICE did not come on to recharge the HV battery. On the face of it, this would appear to be a 12v battery issue. I cannot resolve what meaning this has. Sorry. Flooring the car in Park appears to do nothing to increase SOC. I tried this just a few minutes ago and the Energy Monitor showed no arrows pointing towards the HV battery, so I would assume no energy flow. If anything, just sitting there with the car in Ready results in a continual slow draw on the HV battery. (There is a technique called "force charging" where you put the car in Drive, step firmly on the brake to keep the car stationary, and then step on the gas. In this case yellow arrows do appear indicating charge going into the HV battery.) From my close observations of the energy flows when the car is operating at speeds under 10 MPH, this is exactly what I'd expect, but there is a little surprise to consider. The HSD or more properly one of the computers seems to use 8 MPH as a signal for a control algorithm shift. When your foot is off the accelerator, the "go-pedal," above 8 MPH the default energy flow is blue arrows into the HV battery from regen. However, with your foot off the go-pedal below 8 MPH, the default energy flow is yellow arrows out of the HV battery to MG1 through the Power Split Device and then to the front wheels, moving the car ever so slowly forward. So, when poking along in a traffic slow-down at speeds around 5 MPH, the HSD is drawing on the HV battery even if you're not consciously pushing on the go-pedal. And you draw on the HV battery each time you skooch the car forward a little bit to close up. There are two ways to avoid constant HV energy draw in this situation: * push slightly on the go-pedal to get into "no arrows" glide on the Energy Monitor * when at a stop, press firmly on the brake pedal to stop the slight yellow arrows flow. Lastly, when you are sliding along at less than 10 MPH, always watch the Energy Monitor so you can see what the state of SOC is and which way energy is moving into or out of the HV battery. Hope this helps.
Creeping in traffic will discharge the traction battery. At 2 (pink) bars the ICE will cycle on & off. You saw the results on the MFD. Add the load from the AC & everything happens faster & the situation lasts longer. There is a noticeable reduction in available power at 2 bars but will not last long. You didn't see any green cars because the brakes didn't generate any electricity. At 5mph all braking is mechanical. I can't help with your window "problem". Was the car turned off?
Quote: When I got back into the car to leave, I rolled down my window to ask someone for directions, when I tried to roll it back up it would not go back up. It was at that point I realized I was loosing battery power. On the face of it, this would appear to be a 12v battery issue. I cannot resolve what meaning this has. Sorry. Thanks so much for your detailed analysis!! I'm trying to understand all the technical verbage...but does this mean the windows are powered by the 12V battery, not the main battery, and therefore if the main battery is low, the 12V battery doesn't get charged and if the 12V battery isn't properly charged, my windows won't work? Is this what happened here? Maybe my main battery was being charged when needed? The only other thing I'm confused about is the fact that since I was using mostly (if not the whole time) battery power while I was driving, why was my gas milage so low? The average mpg reading the whole time was around 5 mpg or less. Thanks again.
Keep in mind that running the HV battery down to purple bar will have no affect on the 12V system. There is still plenty of power for the 12V system, which is driven by an inverter from the HV battery. If your 12V system voltage is low it can only be from one of the following: 1) Not in Ready mode, so the ICE cannot recharge the HV battery, leaving no power for the 12V system. 2) Failed inverter so that the 12V system does not recharge. 3) Shorted 12V battery dragging down the 12V bus. Number 2 & 3 are pretty unusual. Tom
Comments by others have highlighted the fact that my earlier comment about the window issues being related to the 12v battery is misleading. When the car is in the Ready condition the 12v system -- which includes the window motors -- is kept at 13.6-.8v by the HV battery through the DC-DC converter [name?]. So even if the SOC shows red bars, the 12v system has plenty of power. I still can't make head nor tail of what the window issue means. Now this is a whole different kettle of fish! When running on HV battery power alone, you see 100 MPG not 5. It took me two days to puzzle through what I know to put together my earlier post. I'm gonna have to think on this for a bit. In the meantime, with luck the folks with a really good understanding of how the HSD operates at low speeds may come up and post. I'll leave you with this. The graph of theoretical maximum MPG tops out at ~100 MPG at 21 MPH. As you go faster, it gradually decreases to ~60MPGs at 60 MPH. When you go slower than 20 MPH, the graph dives very steeply to 0 MPG at 0 MPH. So it would not surprise me that you were saw 5 MPGs at 5 MPH when the Internal Combustion Engine, ICE was running.
by chance can I get a "prius for dummies"? Every time I think I have it figured out, I get thrown a curve ball.
