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Well, I just got home after my car was parked outside in -18 to -21C for nearly 10 hours.

I wasn't expecting the battery to be locked out so easily (people quoted 'days' for this kind of thing to happen), but instead of normal ERDTT to greet me (which I hate enough as it is), the car hesitated for a second when starting, then put me straight into gas mode.

I've been doing some OBD logging to see how ERDTT really works, so I have some data points.

When I parked the car at 0845, outside temp was -18c, battery temp was 16C (I didn't have this in the logged PID list, it seems. It was 16C when I saw the screen in my driveway, I think it's safe to say the computer would have maintained that temp while driving 8 minutes.)

Now that I added battery temp to the logging list, I can tell you the battery will be locked out and you have to use engine when battery is -10C or colder (possibly slightly above this threshold - it never released this mode even at -8).
When I started my car to head home it was 1815, or 9.5h later. It was -21C on the dash display. The temp never broke -18, it actually got colder as the day progressed.
The battery only warmed to -8C by the time I got home, and it was still in pure engine mode.

The engine was not running in typical buffer mode, it was running similar to a regular ICE, in step with accel rate. There was minimal buffering, in that it seemed to still use the battery, but very gently. It wasn't a direct match between pedal and engine, but pretty close.

The only option for mode on the display was Normal and Sport. Hold and Mountain were greyed out. (Not sure why, as it was essentially in Hold mode?)
By the time I got home, Mountain was now an option in the display. Not sure what changed that suddenly made that a viable option.

Regen in L mode felt pretty much like D. Perhaps ever so slightly stronger. But essentially non-existant.
When braking, it appears regen never exceeded 18kW
Accel never exceeded 48kW (probably the 55kW limit, but I never pushed it)

Oh, and fuel economy was absolutely terrible.
 

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At those temperatures, even the best Prius will get worse fuel economy (or not even start!). A Leaf wouldn't even turn on or unlock the doors! You still have the best vehicle out there.
 

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Well, I just got home after my car was parked outside in -18 to -21C for nearly 10 hours.

I wasn't expecting the battery to be locked out so easily (people quoted 'days' for this kind of thing to happen), but instead of normal ERDTT to greet me (which I hate enough as it is), the car hesitated for a second when starting, then put me straight into gas mode.
To me "locked out" would be bricked, unable to move. You'd need more time and or lower temps for that to happen. Instead of being locked out, you were able to drive, although forced to use gasoline.

The car operated as designed, saving your battery from potential damage. Of course plugging in is recommended in these temps. If the car had been plugged in it would have kept the battery warm. Although the Volt's Li-Ion chemistry may be more forgiving (or not), standard procedure is not to charge or jump a frozen battery.
 

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its been 0 F all day today. After sitting 10 hours at the office, my Volt went into the cold battery protect mode when I started it for the 15 mile drive home. The gas gauge flipped into view and the engine basically powered the vehicle for about 12 minutes after which the battery gauge flipped back into view and the engine continued to cycle ERDTT the rest of the way. 0.34 gallons of gas were used and 7 gas miles registered for the 15 mile return trip home. There was 11 miles of battery range left, and 7kWh and 0.5 gallons of gas used after the 30 mile round trip.

It has been colder during the last two winters and I don't ever recall the cold battery protect mode ever operating before. My drive is unchanged over the last few years.
 

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What a coincidence. I was planning to post the same thing. I didn't plug in at work today because there was a parking spot 20 feet from the door and the outlet is 300 feet away. Temp was -3F this morning with wind chill at -30F. Didn't warm up at all through the day. I did remote start from remote link and assume it ran the engine for 10 mins because the cabin was nice and warm when I got to it. I didn't notice if there was a special message when I started the car, but the engine did fire up right away. I was 2 mins into my drive when I noticed that the battery icon was gray and the gas pump icon was active. Since it takes 2 mins to get down to street level in the parking garage, I didn't need much power until 3 mins into the drive. At that point, it operated just like a normal hold mode. I didn't notice any reduction in power and used about 65 kw accelerating up an on ramp. It was about 10 mins into the drive when the engine switched back to normal ERDTT mode. The fringe benefit to this was a very toasty warm cabin.

EDIT: Added photos of dash display. Notice the grayed out 13 miles of battery range in the first pic.
20150107_174003.jpg 20150107_174212.jpg
 

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Happened to me just now. Except hold mode was greyed out but mountain was available. After 10 min or so the battery returned. One other. Strange even, halfway throught my 25 mile commute, while the settings were on Eco auto, the fan turned to full blast. I've never seen it go to 6 before. It seems that most cars only go to 5
 

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My experience today was similar. In my case, the car was in my unseated garage, plugged into my L2 EVSE. I preconditioned the car for 10 minutes. As soon as I unlugged the ICE came on. The exhaust smell was very strong, even though I had just opened the garage door. The dash display read -24c. I drove to the highway, about 3k, at 60km/h then on the TCH at about 105 for about 30km. The ICE cycled on and off repeatedly, always at about 1400rpm. I was in Normal mode, didn't think to check the other modes. The range estimate at the beginning was about 43k, pretty typical in these conditions. The estimate dropped slower than usual, probably because of the ERDTT.

On my way home range dropped to zero a few km from home. ERDTT was on when the switch happened. All that happened was the ICE revved smoothly to about 2400rpm. I didn't have any monitoring on, so I am guessing about the RPMs based on other times when I was monitoring.

I did push the car a bit to see what would happen. Although revs didn't track speed, they did rise when I accelerated. In other words, everything was pretty normal. It was still -24 when I got home and plugged back in.
 

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Discussion Starter #8
That sounds like normal ERDTT, this is essentially battery bypass.
In a newer volt, ERDTT still shows as running on battery in the main display, while this mode switched entirely to gas.
I arrived home with essentially the same charge level as when I started. Battery was bypassed as much as possible
 

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Odd part of this "other" type of ERDTT is that the car will still start the motor even when plugged in and set not to do so.

I did find a few helpfull things.

1. You can get the motor to shut off after a moderately short period of time sort of like it will in hold mode.
2. Once the motor is off you can slowly accelerate to 21mph, if you go 22mph the motor comes on immediately, even if you coast to that speed.
3. I got 16mpg today, about the same as a dodge ram crewcab, seems like they could have done a better job with the volts gasoline action.
4. If you decelerate heavily enough to shut off the motor and you "Very lightly" press the gas and the motor has run a while the car will stay in EV mode, it appears you can't draw over 5kw though and any acceleration turns the motor back on.
Doing this I got the battery gage back but it went away when I had to step on it.
 

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Shouldn't battery heating engage while charging?

I got normal ERDTT today ( about 10F) on my drive home from work. This was my first experience with that, and it seemed to extend my electric range and ease the heat burden as expected.

But I did notice my battery was very cold while charging, and I'd expected the volt to keep it warmer while charging. Here's what I noticed:

I can charge at work only near the end of the workday, and only at 120V 12A. What has me surprised is that I just recently got the ability to read battery temperature and batter heater power consumption (with an OBD reader). And while charging this evening in 10F weather I noticed the battery was not being heated at all.

The battery temperature had dropped from around 12C when I'd parked it in the morning to around 5C when I started charging late in the day, and it had dropped to around 0C(maybe a bit lower) by the time charging had stopped ( about 4 hours later, and by then it had gotten colder out, down to about 8F outside).

When charging completed ( wound up staying at work pretty late so did get 4 hours of charging time today) the battery heating did engage. When it engaged my OBD reader showed about 1.1KW going to battery heat, pretty much all that the on-board charger is capable of at L1. I left about 45 minutes after the charging completed. In that time 45 min, battery heating got the pack temp up a couple of degrees.

I know in conventional LiIon cells, charging at low temp degrade cells with the Li getting more likely to form dendrites. So I expected the Volt to allocate some some of the grid power to heating instead of using it solely for charging. But it doesn't seem to do this. Should it? Would it have done so if I'd been charging at L2?

BTW I'm using an LeLink bluetooth 4 OBD monitor and EngineLink app on IOS with the Volt PIDs referenced in this forum. It works really well. Nice to have a low-cost bluetooh adaptor that works with IOS!

-ken
 

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When I leave for work in an hour it'll still be ZERO degrees F and it shouldn't get higher than single digits when I head home.

My first taste of winter.
 

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Well, I have never seen the 'deep' ERDTT being described here, but just had to chime in that even here in Central Texas, I got the regular ERDTT on my way to work this morning. The center console showed 57F when I left the garage, but rapidly plunged to 28F. At 26F, the engine started, but ran for only 1 mile with .07gal gas used. Note both my Volts are 2011's, so no option to change this behavior.

It's cold everywhere! I don't envy you guys.
 

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At those temperatures, even the best Prius will get worse fuel economy (or not even start!). A Leaf wouldn't even turn on or unlock the doors! You still have the best vehicle out there.
Silly comment, Ray. Used JDM Priuses are the car of choice in Mongolian cities because they start no matter how cold the temperature.

The Volt is *still* an awesome car under all conditions but the Prius won't suffer from the cold.
 

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Your heater may go to 6 but my amplifier goes to 11!

This Is Spinal Tap
Tesla's radio goes to 11, nice touch.
 

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Below 0F (-18C) engine will run continuously to protect the battery. What if you hacked the temp sensor and the car doesn't know it's that cold?
 

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That has been done. Ari changed the resistor, if memory serves, and it makes no difference, other than the ERDTT doesn't occur.

Below 0F (-18C) engine will run continuously to protect the battery. What if you hacked the temp sensor and the car doesn't know it's that cold?
 
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