Charging question!

[mark_91]

Hi all, new Tesla owner and it’s a model 3. I am moving back with family and am deciding what to do with my charging situation. I had a couple of questions:

1. If left plugged in overnight and the charge gets to the set limit (80%) will it stop charging and keep the battery warm? I live in Colorado and this cold weather is taking miles away lol. Or will it just completely stop charging at said 80 percent?

2. What is a decent average in rise of electrical cost with charging at home?

3. Does a mobile charger cost less per month electricity wise than having a normal charger? Or is it basically the same amount?

 

[Tam]

Hi all, new Tesla owner and it’s a model 3. I am moving back with family and am deciding what to do with my charging situation. I had a couple of questions:

1. If left plugged in overnight and the charge gets to the set limit (80%) will it stop charging and keep the battery warm? I live in Colorado and this cold weather is taking miles away lol. Or will it just completely stop charging at said 80 percent?

2. What is a decent average in rise of electrical cost with charging at home?

3. Does a mobile charger cost less per month electricity wise than having a normal charger? Or is it basically the same amount?

1. It stops at the desired setting but it still trickles charge due to vampire loss. As long as there's enough energy, the battery HVAC will turn on automatically as needed to avoid battery damage.

2. You should look at the electric bill. It should increase but not as much as the old electric bill + old gasoline bill.

3. Wall or mobile connector should consumes the same amount if comparing with the same voltage and amperes (like when both are set at 120V 12A or 240V 30A).

 

[fholbert]

1. It stops at the desired setting but it still trickles charge due to vampire loss. As long as there's enough energy, the battery HVAC will turn on automatically as needed to avoid battery damage.

2. You should look at the electric bill. It should increase but not as much as the old electric bill + old gasoline bill.

3. Wall or mobile connector should consumes the same amount if comparing with the same voltage and amperes (like when both are set at 120V 12A or 240V 30A).

1. Are you sure that’s correct? I leave my car plugged in, if it’s not driven for a couple of days I see the charger kick on at the set charge time, a few minutes later it goes back to sleep.

3. I’m not an expert, but I think more power is consumed charging at 120v 20a than 240v 60a. Truth be told, my hangar is more of a man cave than a place to shelter my plane. Recliners, 60” TV, internet access, microwave, refrigerator… The Tesla is parked in the hangar 25’ from me on a 120v charge banging away at 4mph. I hear the fans start and the charge goes down to 2mph, sometimes it stops charging all together. It appears to me, 1/2 or more of the power from the charger is being used to keep the battery at the correct temp. To charge from 10% to 80% would take days. Seems like 240v charging at my home is much more efficient, 10% to 80% is about 5 hours.

 

[Tam]

1. Are you sure that’s correct? I leave my car plugged in, if it’s not driven for a couple of days I see the charger kick on at the set charge time, a few minutes later it goes back to sleep.

View attachment 1013203

3. I’m not an expert, but I think more power is consumed charging at 120v 20a than 240v 60a. Truth be told, my hangar is more of a man cave than a place to shelter my plane. Recliners, 60” TV, internet access, microwave, refrigerator… The Tesla is parked in the hangar 25’ from me on a 120v charge banging away at 4mph. I hear the fans start and the charge goes down to 2mph, sometimes it stops charging all together. It appears to me, 1/2 or more of the power from the charger is being used to keep the battery at the correct temp. To charge from 10% to 80% would take days. Seems like 240v charging at my home is much more efficient, 10% to 80% is about 5 hours.

View attachment 1013213

1) If the vampire loss threshold has not been reached your car wouldn't trickle charge. Neither would it trickle charge after a while if you have scheduled charging.

3) That is not what you asked. You asked about mobile vs wall connector. When compare, they both must be on the same parameters.

Thus, you should ask 120V vs 240v and 20A vs 60A.

 

[brkaus]

The car will avoid damage, but will not keep the battery “warm”. The temperature to avoid freeze damage is quite low.

 

[gsmith123]

The car will avoid damage, but will not keep the battery “warm”. The temperature to avoid freeze damage is quite low.

This is my experience as well - once done charging the car doesn't keep wasting energy keeping the battery warm.

In practical terms, this doesn't really matter and isn't a big deal. In fact you probably wouldn't want to throw away money on electricity to keep the battery unnecessary warm.

I live in Colorado and this cold weather is taking miles away

Regarding this comment OP, cold weather does impact EV efficiency and range pretty heavily. But that's mostly from higher consumption when actually driving (for various reasons, like cabin heating).

And if you have home charging available, then for short trips all of this is a non-issue. Preheat the car (from the Tesla app or with a schedule) if you feel like it. That'll warm up the cabin and the battery. Or don't - the car drives just fine without.

If you need every last mile of range you can get for a long trip from home, maybe you'd care that the battery is warmed up using charger power (maybe!). In those cases you'd probably just set the charge limit to 100% and schedule preconditioning. Easy.