ICE in EV Mode ... Again

at 9 degrees, i wouldn't question it at all. it's 45 degrees that i find baffling.

 

at 26 degrees, and sitting out all night, i suppose you can expect the ice. i guess the question would be does it usually fire or not under similar conditions? it's the inconsistency and lack of control (and understanding of the pip systems) that i find puzzling and intriguing.

 

It may depend on a combination of readings from all the different temp sensors (Torque shows me 3 temp sensors from the batts, intake air temp, cabin temp, ambient temp, etc...) and the length of time it's been at or below a certain temp?

 

do you know the battery temps at the beginning and end of charge on a cold night?

 

Well on our coldest nights we may slip into the 40's, but rarely. We usually hit lowest about 52. And my ICE never turns on unless I run out of range or punch the accelerator to hard.

 

yes, it may be different just slipping out of the 50's rather than climbing from overnight in the 30's, i don't know. but i think some cali people are seeing the ice come on for no explainable reason, which may help validate movie's theory that not all cars are the same.

 

I think there are two things going on at this point from this thread
-ice spinning up to burn off excess regen. This happens at any temperature. Potentially the threshold for "full battery" is slightly lower in colder temps.
-ice spinning up due to low temps. This is a condition that's explicitly described in the manual and the thresholds for that are listed in the FAQ.
The first issue can be resolved by putting the car into neutral before regen happens so that the car uses friction brakes exclusively. The second you can't do much about except for heating your car.

 

my ice hasn't come on in a week or two now, but we have been having very strange weather, if that has anything to do with it.

 

Based on what USB said a few pages back about logging "HV Charge Control" and "HV Discharge Control", I added it to my Torque setup and have been looking at those numbers with my morning commute (40-45F) and afternoon commute (maybe 55F or so when I leave for home).

I think USB is right.. the ICE starting in "cooler" weather has to do with the car's (ECU/BMS/etc) battery protection measures when the battery is cold. With time and more data, we could probably plot a graph that shows how much regen capability the battery can take at certain temperatures.

Looking at HV Discharge Control (which I believe is the maximum allowable regen expressed as "horsepower"), you can see that as SoC decreases, HVDC increases (or allows more regen). From my limited data, I can also see that if the battery temps are higher, maximum HVDC is also higher at the same SoC.

Having said all that, what I think is happening in MY case is once I'm moving at or around 40MPH and MG1 is somewhere around 5000RPM and my SoC is around 83%, the POTENTIAL for regen to spike well beyond the limit set by HV Discharge Control is what is forcing the ICE to start up. So even though when I leave my house I make an effort to ensure I am never in regen territory, once MG1 is at a speed where regen COULD go beyond the limit, the ICE will start.

Also keep in mind that when I leave my house, I AM going downhill (but as I said before, keeping it out of regen). So more than likely, the car also factors in how much energy is being consumed and how fast the car is moving/accelerating to determine if the potential for high-regen is there.

Anyway, that's all I needed to know. I think with more monitoring of the "HV Discharge Control", battery temperatures, and SoC, we can get a better idea (plot a graph) of how temperature affects regen and if/when the ICE will start up.

 

i like it track, thanks for all the work you've put into it.

 

Tracksyde, have you tried switching to neutral to completely eliminate regen possibility?

 

Yeah, switching to neutral has always worked for me. But ever since I ran into the "excess regen" issue, I've always timed my "braking" (relying more on friction braking) so that when I did come to a complete stop at the Stop sign, I'd be at about 83.9% SoC without the ICE firing. This has worked for me for the past 8-9 months or so.

Its only in the past 3 weeks or so where my "standard operating procedure" was not enough to prevent the ICE from kicking on that made me wonder what was going on, even though I was well below the 83.9% threshold I was so accustomed to from before.

Now I at least know that with cooler temperatures, it may not be possible at all for me, in my situation, to time my braking to get maximum regen without triggering the ICE.

 

Ah, got it. Good luck!

 

Tracksyde, remove the multiplier to view it in kW. It is easier to compare with the battery pack amp and volt.

If the charge control displays 10 kW, and pack voltage is ~200V, you dont want to exceed ~50 amp.

For the purpose of logging to determine/prove the cause of ICE starting, I guess it doesn't matter.

 

this morning, i left with full charge, 12.6 miles. 45 degrees in the garage, 32 degrees outside. got to my usual spot where the ice tends to fire up. hit the top of the hill at 25 mph and 12.2 on the charge. kept the hsi at 1/8 - 1/4 to the right of the charge line. hit the bottom of the hill at 35 mph. started to press the gas for the uphill and wham! on came the ice. this hasn't happened in a few weeks now, and the first time with temp in the 30's.

 

Lol the mystery continues.

 

I That does seem a little quick, what is the voltage at the outlet? The higher it is, the quicker the charge and VICA Versa.

 

well.....it's time......time to drive my PIP in EV, I just finished charging my battery, took 2 hours and 42 minutes, a bit longer than the 2 hours and 34 minutes I experienced a couple of months ago. Tomorrow I will fill up my tank with fresh Gulf Coast BP gas. Drive my usual 2.7 miles to work at 6:00 am. Temperature should be around 20 degrees. I will be driving down the side streets that have a maximum of 25 MPH at about 15 MPH. wish me luck!

 

Andy, have you seen my charging stats at ATTENTION KILL A WATT NERDS?

 

No I have not, I know your stats are always teriffic. Incidentally, I have been telling people to search on Priuschat. I now find, there is no search box ??? Am I missing something?