Long charging times with level 1 charger
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Yep!!! And, I suggest that anyone running a new dedicated 120V 20A circuit, should drop the wire gauge by 2, below the minimum/recommended gauge (eg: if the required gauge for the amperage and distance is 14, then use 12).
(Same applies if you are running a 30A 240V)
When running at full capacity, there'll be less line loss, less heat, and you'll be able to pull more power without either (a) tripping a breaker and/or (b) heating up a wire.
We used to run into those issues when people would try running lights off "commercial" 20A extension cords on our film sets, instead of off our much thicker gauge "stingers" (outlets to lights, used like extension cords) and "stringers" (distro boxes to outlets).
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In the case of the stringer in the photo, they're three phase, which also helps.
(Same applies if you are running a 30A 240V)
When running at full capacity, there'll be less line loss, less heat, and you'll be able to pull more power without either (a) tripping a breaker and/or (b) heating up a wire.
We used to run into those issues when people would try running lights off "commercial" 20A extension cords on our film sets, instead of off our much thicker gauge "stingers" (outlets to lights, used like extension cords) and "stringers" (distro boxes to outlets).
In the case of the stringer in the photo, they're three phase, which also helps.
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1,525 Posts
I would've guessed closer to 25 hours from 46% to 100, but that's ignoring losses. As @jmwk mentioned, the L1 EVSE only puts out max 1.44 kW. To charge from 0 to 100 would take close to 46 hours, assuming 12 amps at 120v.
That sounds about right. Here are the calculations, if you're interested in how it works.
If you're at 46%, that means you need to add 54% to fill the battery. At about 64kWh usable, 54% means you need to add about 34kWh to fill the battery. Level 1 is 12A at 120V. That's 1.44kW. Assuming no losses, you could fill the battery in about 24 hours (34kWh/1.44kW). Assuming 10% loss, which is more reasonable, more like 26 hours. If it's conditioning the traction battery, charging the 12V battery, or conditioning the cabin at all, that will increase the time.
Charging time on level 1 varies a lot depending on external temp. The battery likes to be around 0C or 32F when charging at level 1 or 2. Depending on ambient temp, the battery heater may be on to get the battery warm. On level 1, esp when the weather is very cold, a great amount of energy is being used by the battery heater instead of going to the battery. Charging will be less when the temperature is warmer.
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And also, at Level 1 (1.44kW gross), if the temperature is cold enough, the battery heater might consume so much of that power that you wouldn’t get much or any effective real charging. I am not sure how much power the battery heater can consume, but I am pretty sure it’s got to be close to the 1.44kW level in order to bring that large mass of battery cells up to temperature.
L2 charging (6.6kW max for the Solterra) is much more likely to be able to run the battery heater and supply enough power to actually charge the battery.
I am working with a company which is analyzing Canbus data captured from my car to see which useful things we can get from the car.
Perhaps I’ll push a bit more on the battery heater data, if it can be separated from the normal A/C power consumption data. I’ll also take another look at the schematic for how the battery heater portion of the system works, but my first memory of it is that it is part of the heat pump system, and power consumption might not be broken out separately. It’s also not cold enough where I live to get a good feel for how much of the 1.44kW L1 power available would be consumed by the heater.
I think that the limited information Toyota has been saying about the battery heater (and improving/changing hardware aspects of it) is leading me to believe that they under-engineered that portion of the system and all of the early-adopters are screwed if they live in or frequently visit very cold areas. That said, the car works great for me in temperate coastal California, and people in cold climates should find someone in a moderate climate to buy their 1st-gen car.
Seriously, try L2 charging, even if you have to limit it to 16A at 240V (like a 20A 240V outlet). You’re still at 3.84kW, which is way better. And if you have a full 32A available, you’re at 7.68kW, which after AC charger losses (in the car), gets you the full 6.6kW it charges at (from my observations of reported battery voltage and current from Canbus, and the reported power consumption from my EVSE). Actual current consumption at the EVSE is usually 30.7A or so at 240V or 7.368kW. The battery system reports 6.6kW charging and the efficiency is about 90%.
L2 charging (6.6kW max for the Solterra) is much more likely to be able to run the battery heater and supply enough power to actually charge the battery.
I am working with a company which is analyzing Canbus data captured from my car to see which useful things we can get from the car.
Perhaps I’ll push a bit more on the battery heater data, if it can be separated from the normal A/C power consumption data. I’ll also take another look at the schematic for how the battery heater portion of the system works, but my first memory of it is that it is part of the heat pump system, and power consumption might not be broken out separately. It’s also not cold enough where I live to get a good feel for how much of the 1.44kW L1 power available would be consumed by the heater.
I think that the limited information Toyota has been saying about the battery heater (and improving/changing hardware aspects of it) is leading me to believe that they under-engineered that portion of the system and all of the early-adopters are screwed if they live in or frequently visit very cold areas. That said, the car works great for me in temperate coastal California, and people in cold climates should find someone in a moderate climate to buy their 1st-gen car.
Seriously, try L2 charging, even if you have to limit it to 16A at 240V (like a 20A 240V outlet). You’re still at 3.84kW, which is way better. And if you have a full 32A available, you’re at 7.68kW, which after AC charger losses (in the car), gets you the full 6.6kW it charges at (from my observations of reported battery voltage and current from Canbus, and the reported power consumption from my EVSE). Actual current consumption at the EVSE is usually 30.7A or so at 240V or 7.368kW. The battery system reports 6.6kW charging and the efficiency is about 90%.
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I've done limited to zero L1 or L2 charging when the battery pack is cold (my garage is heated, about the only away-from-home charging I do is DCFC), so I have little to no first-hand experience with this. Is this a known fact that the "battery heater" consumes power when the car is being charged by AC (L1/L2), when the battery pack is cold?
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I haven’t had any issues charging with level 1 in Minnesota over the last couple weeks but my garage hasn’t really been dipping much below freezing.
Still planning to put in a level 2 because it is effectively free with all the rebates and discounts my electric company offers. Half off on electric rate if I only charge overnight? Sure!
Still planning to put in a level 2 because it is effectively free with all the rebates and discounts my electric company offers. Half off on electric rate if I only charge overnight? Sure!
The text below is from page 97 of the Owner's Manual. It's pretty clear that charging speed is reduced if the BMS determines the battery needs to be warmed up. As @n6nl mentioned, L2 charging, even at a low amperage, should help a lot.
●When Traction battery heater is
operating during charging, the
charging may take longer than
normal.
●The remaining charge of the traction
battery declines when the
traction battery heater operates, it
might be necessary to recharge
the traction battery again in order
to supplement the remaining
charge.
What I find interesting is that in the previous column on that same page, it states that that the traction battery heater will stop if the charging cable is disconnected (or after 3 days). That implies to me that the battery heater only runs while it is plugged in. Combine that with the second statement below, that the traction battery discharges while the battery heater operates, and it seems to me that you could lose battery charge if charging in the cold -- if the BMS chooses to use more energy for the battery heater than is coming in from the wall. Perhaps it's just poorly written or I'm misinterpreting.
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