Yeah my understanding is that the "traction battery heater" actually heats the battery up. I recall 0°C/32°F as the threshold. If the temp is below that, the battery heater comes on and warms the battery back up to freezing. The traction battery warming control just ensures the battery doesn't drop below a set temperature (whatever Toyota chose) so the battery temperature will start below freezing but at least it will start.
I had my car plugged in last night, then went on a trip to pick up someone, it was about 7 degrees outside, ICE kicked in about two miles into the trip. Good news is I got 60 MPG on a 32 mile round trip
Ohh? Were you in EV Auto? or EV? The heater works down to about 14°F so maybe that's why the engine came on? Isn't that what I said?
So First 3 days = heater to maintain near 0°C/32°F (I can't remember where I got the number... probably the asst. engineer) Day 4 onwards in Canada and Alaska, it'll just ensure the battery doesn't get so cold that the car can't start.
I'm not sure if I was in EV auto or just EV the green EV icon had a line around all four sides of the EV icon (sorry that's the best I could describe the Icon) so is EV in Auto or not? And I kept the front defroster off (didn't need it on) update: looks like I had it in EV mode
It's all about the chemistry. Electrical resistance increases significantly in lithium batteries when they drop below freezing (32°F, 0°C). That's part of the reason why winter range is less. Being able to avoid that cold penalty is a nice upgrade.
The common Li-ion chemistries literally can't be charged when the electrolyte is below freezing. They have to be brought above 0C before charging. Because of cost, the Prime, and nearly every other plug in likely use a 'common' chemistry. So the Prime, likely every other plug in with air cooled batteries, has a simple heater to keep their pack above freezing so charging is possible. Yes, but a recommendation to set charging to have it finished before a planned leave time is because the act of charging will heat it up further so it will be even warmer for the start of the drive.
-6°F charging the other day worked fine for me. Set the timer to charge late in the day, after a long cold stay in the parking lot.
Were you able to monitor how much the battery temperature dropped before charging began? "Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a sub-freezing charge. This is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing. Advancements are being made to charge Li-ion below freezing temperatures. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30°C (–22°F) is 0.02C. At this low current, the charge time would stretch to over 50 hours, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10°C (14°F) at a reduced rate." - Charging Batteries at High and Low Temperatures – Battery University I'm sure Toyota can have the charger supply a lower current for freezing temperature, and the manual even states that low temps can extend the charging time.
No, I'm parked too far away to check. The app for ChargePoint doesn't provide fine detail either, just basic data points. However, it does show enough though to see an extra 10 minutes of lower-amp draw though before full power. That certainly looks like a warm-up period.
it seems to me, that this battery pre heater is pointless, if it isn't providing more cold weather range. we haven't had one report of a car not starting due to the cold. i'm sure i'm missing something here.
The heater does make a difference, I can go 35mph or faster when the outside temperature is 40 degrees or lower as long as it's above 14 degrees, my old pip the ICE would kick in if I went faster than 25mph Posted via the PriusChat mobile app.
