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From what I've seen in analyzing heat records, charging doesn't start until the ess_min_temp reaches 6*C.
Yes. I think the min temp for regen / charge is 6*C
Yes. 6*C What I think is more telling would be to plot the sleep temperatures across the 8 hour period when the outside temp was -10*C. This would give us some idea of how the battery mass responds to cold temp.
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Yes it is. From what I can tell from the log heat and charge1m records, the heater in the ESS runs off of the battery directly. This makes sense because drawing current from the battery, heats the battery too.
I parsed a log from one owner during a pre-charge heating session. The current draws are as follows, I_ESS =-0.88A @ 400V, I_line = 0.2A @ 240V. So the total power used is 352W + 48W. My guess is that the ESS heater is about 300W and the power drawn from the line would increase with a battery that is more depleted.
I have my car in storage mode at the moment, as the weather is expected to be crappy for a while and I don't have snow tires.
I happened to open the driver's door today to look at something, and the touch screen went BEEP-BEEP and flashed up a message that I didn't have time to read.
After that I heard the contactors turn on, and the battery pack started preheating. Now that's odd, since it's in storage mode, and the car is obviously NOT going to charge this evening because it's over 85%. At least, it shouldn't. I won't know until 1 am when the charge is scheduled to start.
The touch screen showed "Preparing to Charge" and 7-8 amps 240 volts. Clearly it was preheating the battery.
Last I checked it the charge lights were blue, and the circulation pump was running, and it's still showing "Preparing to charge", but the current is now at 0 amps. I assume the battery has warmed enough.
Obviously a firmware glitch of some kind. Not a big deal if all it did is waste 6 cents of electricity. But I'll have to see what it does at 1 am.
I happened to open the driver's door today to look at something, and the touch screen went BEEP-BEEP and flashed up a message that I didn't have time to read.
After that I heard the contactors turn on, and the battery pack started preheating. Now that's odd, since it's in storage mode, and the car is obviously NOT going to charge this evening because it's over 85%. At least, it shouldn't. I won't know until 1 am when the charge is scheduled to start.
The touch screen showed "Preparing to Charge" and 7-8 amps 240 volts. Clearly it was preheating the battery.
Last I checked it the charge lights were blue, and the circulation pump was running, and it's still showing "Preparing to charge", but the current is now at 0 amps. I assume the battery has warmed enough.
Obviously a firmware glitch of some kind. Not a big deal if all it did is waste 6 cents of electricity. But I'll have to see what it does at 1 am.
About -6C when I left work today. Battery showed in yellow in the VDS (first time I've seen this)
Based on the logs I just pulled, the ESS was below 0 -- also the first time it's been below zero. The coolant was -4C. 7 minutes later, the yellow disappeared (ESS min temp was 0.5C)
Based on the logs I just pulled, the ESS was below 0 -- also the first time it's been below zero. The coolant was -4C. 7 minutes later, the yellow disappeared (ESS min temp was 0.5C)
Doug,
I also have mine in storage mode (almost full standard charge on it). When I opened the door, the message that flashed up says something like " When in storage mode, plug in the vehicle". When the car is asleep and you open the door, the communciations between the charge port and the PEM probably hasn't registered before the message comes up. Anyway, the message disappears quickly and the car does its communications giving the blue light. A few minutes later it goes back to sleep. I don't recall mine doing the "Preparing to charge" message, but since it was way over 50%, it did not initiate a charge...just the blue light for a few minutes then sleep.
I also have mine in storage mode (almost full standard charge on it). When I opened the door, the message that flashed up says something like " When in storage mode, plug in the vehicle". When the car is asleep and you open the door, the communciations between the charge port and the PEM probably hasn't registered before the message comes up. Anyway, the message disappears quickly and the car does its communications giving the blue light. A few minutes later it goes back to sleep. I don't recall mine doing the "Preparing to charge" message, but since it was way over 50%, it did not initiate a charge...just the blue light for a few minutes then sleep.
Mine did not intiate the charge, either. It simply preheated the battery for no reason, and then went dormant again. It's probably a timing issue of some kind.
Those "spikes" look pretty normal to me. Thermostats typically work as a "bag-bang" controller with hysteresis. When the temperature drops to a certain point, the heat swiches on. The temperature increases and then the heater is switched off again. That cycle produces a sawtooth appearance to the temperature profile.
-26C Weather
in this post I talk about the performance of my Roadster in severe cold.
One of the things I discovered is that my car seems to consume a lot more power than normal when regen is disabled due to cold. The total loss of range seems to be about 10 km. Once the car warms up consumption returns to normal.
in this post I talk about the performance of my Roadster in severe cold.
One of the things I discovered is that my car seems to consume a lot more power than normal when regen is disabled due to cold. The total loss of range seems to be about 10 km. Once the car warms up consumption returns to normal.
So the night of the 24th into the 25th was pretty cold (0F at 9PM). The car was plugged in from 7:26pm to 9:24am (14 hours). It consumed 6.6KWh of power heating the battery. At my local 15 cents per KWh (includes power generation and distribution charges, which are separate rates on my bill), that's $1.
The VDS says I charged for 1:46 at 9:57pm consuming 15KWh. According to the logs, my charging started at 8:11 (after the heating cycle, from 7:26 to 8:11) and ran until 9:57 consuming 16.8 KWh (as measured by line (wall) current and line voltage, NOT ESS current and ESS voltage). So the VDS appears to be displaying KWh into the ESS and doesn't speak to power used by heating at all. Keeping the battery heated for 14 hours was 40% of the energy used to charge it for 2 hours.
Edit: FYI, the battery heater ran for a total of 3.3 hours (consuming 2KW) during the course of that 14 hours.
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I detect a firmware feature request: option have the battery NOT heat until after the charge is completed. That way you can dial it in to charge in the wee hours, and have a nice toasty and freshly charged battery when you head out in the morning.
This doesn't make any sense, they only reason the battery is heated is to safely charge it. The battery must be above 32F to charge.
Right, and regen = charging. The heating function was added by popular request. I'm suggesting a tweak to save energy.
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