Range of battery state of charge?

i think the bottom is 40%.

 

I was recently driving on a winding, dead-flat harbourside road for 3-4 miles, steady traffic at about 20-25mph. P n' G wasn't possible because of close vehicle spacing, and the need for a very light touch on the gas pedal. My SoC started at 60+, steadily declined to 39-40, at which point the ICE boosted SoC to 45. This pattern repeated several times until I was able to get past the traffic. My dash display would just pull 3 bars at 45, then soon drop back to two.

 

Do the bars change colour when there are only two of them?

 

Yes, the Battery Management ECU controls the HV battery SOC between 40 and 80%, which is what is indicated on the battery display on the MID. When driving steady-state the ECU will try to control at an optimum 60%, leaving room for regen charging current and also delivering current when needed.

The last two bars do not change color on my 2010. The Gen II display changed colors but the Gen III (2010 at least) display does not change color.

 

They do not change color at any percentage on the C.

 

Hi mdgates,

Under moderate power demand(ECO driving range), the system tries to keep the SoC between 40% and 80%.

However, I 've observed SoC dropped to 37.6 ~ 38.0% during warm-up when my SoC at start-up is close to 40.0%. If I feather the accelerator, the system seems to allow the SoC to drop below 40.0% while engine concentrates on warming up. After engine has warm up, the system will try to keep the SoC above 39.6%.

There is another scenario where SoC can drop to as low as 33.3% reported in this thread. It was on a Yaris Hybrid that uses the same HSD as c. In that thread, the engine was running at max. RPM and HV battery at max. sustained output of 120A in the red Power zone. Once the SoC dropped to 33.3%, there was no more assist from the HV battery and the HSI dropped to ECO/Power zone intersection.

The Repair Manual says the system will log a history code if SoC drops below 30%.

Vincent

 

You always have informative posts Vincent. TY

 

I've had mine down into the 34.x% range during warm up on numerous occasions. It happens if I park at work with low SoC, because essentially what happens when I leave work is that my ICE doesn't start until I leave the car park and then after a short distance I need to turn into a slip lane of a major road, starting with a tight 90 degree turn. The slip lane is not very long, the road is 70 km/h with traffic going at that speed or above and it's uphill, but you have no choice... once you're in that slip lane you've got to get up and go and assert your move into the main road.

The car will do it, but the SGII shows the AMP draw over 100 and that's when my SoC plunges. As soon as I'm established in the main road at 70 km/h, I level off at that speed and the car starts to defend the battery as I go over the crest of the hill.

 

To prevent this, I've started to encourage the ICE on immediately, either by brake + accelerator or starting the car right when I get in and before fidgeting around (because the ICE seems to start after ~10 seconds regardless).

 

Not in Southern Hemisphere c's it doesn't. You can sit there for ten minutes if you like. Unless the SoC drops below 40%, the ICE doesn't start until the first time you push the HSI past the middle mark. This is why in the scenario I described it is literally right as I'm starting my run up that the ICE comes on.

I'm not fully convinced the brake + accelerator thing is an appropriate thing to do with this car. I do see it is more popularly suggested by Gen II owners, which I find interesting but haven't dug into further. I generally take the view that the car's judgement is fine for most things. If you need it to move and put your foot down - or if it really does need to defend the SoC - it can and does break out of its warm-up cycle early and let the LOD escape its ~60-70 restriction and push up to its normal levels in the 90s. If you ease up it will drop back until the normal conditions to end the warm up cycle are satisfied.

In the past when I've wanted to try forcing the warm up cycle to start, I've simply pushed the HSI past halfway momentarily while moving slowly, it's easy enough to do, but I stopped doing that because I just didn't seem to be gaining any advantage from doing so.

 

I am no longer so sure of this southern/northern difference, Rob. You will know that Auckland's climate is very temperate, courtesy of major oceans either side. Our annual temperature range, unlike yours, is about 40F to 85F. As a consequence the C's climate air is more of a curiosity than a necessity for me; I suppose I have used it 5-6 times in total, preferring and only needing to use the windows/mini-weather-shield combo.

However, I have noticed that when I did use it, and shut down with the climate air Auto left on, on restarting next day, the car remembered the Auto setting and the ICE kicked in almost immediately, instead of 100 metres up the road. I observed this 3-4 times. I should add that I use EV mode all the time.

Our northern friends use their climate air a great deal, given their temperature range. I imagine many of them leave their climate air on all the time, which may account for their many posts suggesting an immediate load triggering the ICE when starting.

 

That's different. Sorry, although I use a/c for most of the year, as I always have the a/c switched off when I shut down, I had forgotten that this is another item that will cause the ICE to start if it hasn't already done its warm up cycle.

While I am sure many of them do leave a/c on, it's been firmly established that their ICE warm-up starts by itself when they start up. They have a short window of opportunity to hit the EV Mode button to override this operation. This is the only way they can do it.

Does the ICE always come on after startup? | PriusChat

 

Interesting. Lately, I have been doing what you described in the last paragraph (forcing the ICE on by pushing the pedal past the EV range) so I'll try to do that if the ICE isn't on by that point. I'll also try to not do it a few times to see the difference. I turn onto a main road that sometimes has traffic about 20 seconds after backing out of my parking spot, so I usually try to stay in the EV range while getting up to speed (35 mph) on that road but if there are cars coming in both lanes, I push it a bit farther, which drops me down to below two battery bars.

My climate control is almost always off and the ICE still starts within 10 seconds of starting the car. The only way to prevent that is to push the EV button before that 10 seconds is up, and to be very light on the accelerator.