L2 charging (220v/12A) ...Why is it warming battery for 30 minutes before starting to add miles?

[fbitz777]

Not that cold (29F) and battery at 32F.... why is my home L2 (220V/12A) charging session wasting 30 minutes warming up battery for 30 minutes until the battery gets to 50F? So for 30 minute no miles are being added!
Never seen it do that that before so I wonder if this is new behavior.

If I go the EA DC supercharger I get it to start charging immediately; although limited to about 24kW.

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[ATL_R1S]

Not that cold (29F) and battery at 32F.... why is my home L2 (220V/12A) charging session wasting 30 minutes warming up battery for 30 minutes until the battery gets to 50F? So for 30 minute no miles are being added!
Never seen it do that that before so I wonder if this is new behavior.

If I go the EA DC supercharger I get it to start charging immediately; although limited to about 24kW.

It's not wasting anything, it's literally making your battery charge and discharge more efficiently. Batteries charge and discharge most efficiently when warm. The latest update can do so on a user-defined schedule so that on cold days, you won't see as big of an efficiency hit on the first 30ish minutes of a drive due to a cold-soaked battery. It is one of the most celebrated new features in the OTA.

If you don't have the climate scheduling turned on, the vehicle was likely warming the battery up anyways so it can charge (then discharge while driving) more efficiently than when it's very cold, as indicated. You should appreciate that it's doing so versus being concerned and feeling like it's wasteful.

You should watch this:

 

[Carmelbythesea]

I got this message when I plugged in the morning. I’m in CA and the temp was 45F. Never seen this before.

 

[Redline]

Not that cold (29F) and battery at 32F.... why is my home L2 (220V/12A) charging session wasting 30 minutes warming up battery for 30 minutes until the battery gets to 50F? So for 30 minute no miles are being added!
Never seen it do that that before so I wonder if this is new behavior.

If I go the EA DC supercharger I get it to start charging immediately; although limited to about 24kW.

Its doing exactly what its supposed to be doing with a cold battery.

 

[fbitz777]

Its doing exactly what its supposed to be doing with a cold battery.

NEVER did it before at 30F to 49F as it did today for L2 charger. And I have had 7 Evs and none has done that.

Under your reasoning it will take hours to start charging at 110V!

Heck it accept 24kW in DC charging mode at 30F (i.e. it adds miles right from the start)

 

[Redline]

NEVER did it before at 30F to 49F as it did today for L2 charger. And I have had 7 Evs and none has done that.

Under your reasoning it will take hours to start charging at 110V!

Heck it accept 24kW in DC charging mode at 30F (i.e. it adds miles right from the start)

I've seen people lose range on 110v in the cold FYI.

 

[fbitz777]

I got this message when I plugged in the morning. I’m in CA and the temp was 45F. Never seen this before.

Never got that before either!

 

[fbitz777]

I've seen people lose range on 110v in the cold FYI.

30 F is NOT cold!

If you don't have the climate scheduling turned on, the vehicle was likely warming the battery up anyways so it can charge (then discharge while driving) more efficiently than when it's very cold, as indicated. You should appreciate that it's doing so versus being concerned and feeling like it's wasteful.

You should watch this:

Hey I WAS driving the truck for 20 minutes before I started my L2 session and during that drive I did not see the truck warm the battery (looking at motors temps). Again 30F is NOT that cold.
My dispute is that I can go to DC charger and it will take 24kW in right away vs 0kW via L2.

 

[Redline]

30 F is NOT cold!

Hey I WAS driving the truck for 20 minutes before I started my L2 session and during that drive I did not see the truck warm the battery (looking at motors temps). Again 30F is NOT that cold.
My dispute is that I can go to DC charger and it will take 24kW in right away vs 0kW via L2.

I didn't say 30f was that cold. I'm giving you an example.

 

[SSteveEV]

Charging on 110 can be rough. This was in a 64* garage and somehow the vampire drain ate 1/3 of the juice over 42 hours.

 

[HaveBlue]

You should consider looking at the wire gauge in case it's #12 instead of #14. You could upgrade to breaker to 20A 240v and get more out. Is it a 6-15 outlet?

 

[fbitz777]

I now tried on other L2 charger at my garage which is L2 30A output:

I started at 47F battery and it took 7 minutes to start adding miles into the car! Note that during the first 7 minutes it actually LOST miles to charge battery (-0.5kwh)

 

[fbitz777]

My point on this thread is I can go down the road to DC fast charger and start charging and add miles immediately.
See attached I start with same battery temp (47F) and it immediately puts 45mi/h at 27kW until the battery reached 50F (took 8 minutes)

Note that in both case (7kW L2 and DC charger) 1.1kwh was uses to warm battery which implies that 9kW is how much power the motor inverters can handle in battery heating mode.

 

[Dark-Fx]

It's not a complete waste to plug in L1/L2 for very short periods. Your driving efficiency is going to go up with a warmer battery, so while you feel like you feel like it should be "more energy in the pack is better", I think Rivian probably has the data to know what they are doing here. L3 charging is obviously a different monster because the amount of energy being added will exceed what they can "waste" as battery heating.

 

[usofrob]

I've seen people lose range on 110v in the cold FYI.

I've definitely lost energy in my old Tesla Model S in the sub freezing temps. I was on a trip and had parked my car in the airport parking lot. They had shared 120V outlets there and I though, hey why not? Well, I checked on the car the next day and the percentage had gone down, not up. Thankfully I was able to disable charging so that we didn't come back to the airport with a dead battery.

I have been able to use 120V to add range in the winter if I have a dedicated outlet and charge it as soon as I get there.

tl;dr Only charge from a 120V charger when the battery is warm. (At least for my old Model S.)

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