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120V charge rates at different temperatures

120V charge rates at different temperatures

Anyone ever see a table of 120V Model 3 charge rates at different temperatures? Where I live it's been down to -30 deg F recently. It's be handy for trips to locations where that's the only available option. For the LR battery, I believe it's 4 or 5 mph at 70F, and I think it's actually a negative number for below 0 deg F due its inability to keep up with battery heat loss. Otherwise, anybody have personal experience to share regarding this?

whosyourbaba | February 8, 2019

I don't have exact numbers or graphs, but I use regular outlet primarily for charging. During chicago polar vortax at -10F, the 120V could not add a charge, kept the battery the same. I can gain charge but slower at +10 and pretty much pass 40F I feel the rate is about the same.

Teslanene | February 9, 2019

@whosyourbaba if you didn’t plug it in where you losing 3-4 miles per hour at -10?

msmith55 | February 9, 2019

The temperature does not directly affect charge rate, only indirectly by diverting charging in favor of battery warming, which has priority, as a cold battery can not be charged, it would damage it and cause the battery to burst into flames when charged. Fortunately the BMS automatically has temperature sensors which detect when the battery is too cold, and turns on battery heating instead, and as soon as battery is warmed switch back to charging. Also, battery warming requires 6 kW and 120 V only provides 1.5 kW, the rest comes from the battery. Thus it can require 3 hrs charging to replace 1 hrs of battery warming. Charging appears slow or discharging is possible. If battery charge is low, (below 20 percent?) Battery will protect itself, and no warming or charging will occur.

whosyourbaba | February 9, 2019

@teslanene honestly I'm not sure, I didn't want to try when it was so cold. Overnight when I park unplugged when it is 10 to 20 degrees F outside, I lose 3-5 percent, which isn't terrible to me.

@msmith55 agree with you, even with 10 plus hours of charging in the extreme cold, my battery on the AP still has blue or when I drove it still had the snowflake. But I can stay the same percentage, even when I was charging for 14 hours. My interior temp even read -13F when I randomly checked.

philippem | February 9, 2019

Around freezing point, you get about 1% per hour. I think that when it is really cold, charging mainly compensate what you would lost if the car was not plugged. While batteries cannot accept lot of charge when cold, I do think that level 1 or level 2 charging are not that much affected. However supercharging is affected a lot.

TM3Q | February 9, 2019

Like right now it’s -11 Celcius and charging with my mobile 110V charger, it changes from 7 km/h to 0 km/h then back to 7 km/h in intervall so average 3-4 km/h.

It’s always better to plug it even when frigging cold because you never will loose any battery mileage and I can confirm because last time it was -25 Celcius and the battery recharged at average 3 km/h for 17 hours.

You shouldn’t loose any battery charge while plugged unless you start preheat the cabin then you will deplete the battery because the power supplied from a 12 amp 110V charger isn’t enough to do all the climate heating.

TM3Q | February 10, 2019

This morning I checked my battery and it's reached 415 km (259 miles) and started yesterday at 350 km (219 miles) so gain 65 km (40 miles) in 16 hours wich average 4 km/h (2.5 mph) recharge. Outside temperature is -15Celcius (5 Farenheit).

One last important thing, you don't get the blue snowflake icon while plug in the 110V while recharging so this means I don't have to preheat my battery when I leave this morning to drive back to Quebec city, just have to preheat a little bit the cabin with climate ON and this will deplete the battery but it's normal and will just need like 10 minutes warming instead of the 30-60 minutes from a frozen battery!

So no matter what if you can plug your car in a 110V outlet just do in in freezing temperature, it's worth it and your Tesla will be a happy car :-)

Cheers