Level 1 home charge rate newbie question

[SudokuJW]

So just got my first Tesla and I have a newbie question. 2017 MS P100D

I did some searching and couldn’t find it so sorry if it’s been asked.

My question is only for battery health and not cost consideration, in my scenario I want to charge to 80 percent. I’m currently using 120 volt outlet.

I plugged it in last night and it projected at 12 amps charging would be complete at 0400.

I did not need it to be complete until much later so I adjusted the current to 9 amps and let it go with a projected charge completion of 0900.

My question is:
Is it better to use the lowest current possible over the longest time to arrive at your desired charge right before leaving

OR

Better to schedule a charge start time using highest current (12 amps) therefore less overall charging time, also planned to reach desired SOC right at departure.

So another way would be to ask:
6 amps of 15 hours or so
Or
12 amps for 7 hours or so

 

[Cosmacelf]

I would never reduce amperage on 120v, you are wasting electricity. The car uses extra electricity when charging, so when charging longer, you are wasting more. See the calculator at the bottom of this page to compare costs when charging at 120V vs 240V charging for example: Advice for EV Charging in North America

 

[SudokuJW]

Interesting, this is a temporary situation as I am installing a L2 charger.

I’m just curious about the battery health aspect.

 

[Cosmacelf]

Interesting, this is a temporary situation as I am installing a L2 charger.

I’m just curious about the battery health aspect.

No difference in battery health for any level of level 1 or 2 charging. It’s all slow relative to Supercharging.

Out of curiosity, what level 2 EVSE are you installing and at what amps?

 

[Cosmacelf]

The only time you’d want to think about doing something different with level 2 charging is when you need to charge to 100% for an upcoming long trip. In that case, you want to minimize the time spent at 100%. Oh, and never charge to 100% if you are at a ski mountain and heading back down, since you won’t be able to take advantage of regenerative braking.

 

[SudokuJW]

Haven’t done my research just yet as to which charger.

It looks like do to my home service I’m going to be limited to 30 amps.

 

[Cosmacelf]

Haven’t done my research just yet as to which charger.

It looks like do to my home service I’m going to be limited to 30 amps.

I’d still recommend the Tesla Wall Charger. For a premium product (Ie not a cheap Chinese knock off that has no UL listing), it is priced very competitively.

What is your main panel service amperage?

 

[SudokuJW]

200 amps.

I will definitely consider the Tesla charger.

My electric company will give me 500 dollar credit if I purchase a certain charger and charge off peak hours.

I need to figure out what they allow.

 

[Ostrichsak]

As has been already stated, your battery pack was developed to withstand hundreds of times higher current than anything you're going to install in your home.

Therefore, your debate about a few amps here or there quite literally means nothing to the health of your battery pack. Anything up to level two is going to seem like a slow walk for Usain bolt comparatively. Whether it's at 0.1 or 0.2mph for someone capable of running at his speed is of no impact.

Your BMS will have a set overhead to handle charging no matter what. The longer you drag it out the more electricity you're wasting. The best answer is to just charge at the maximum safe allowable for the particular source or circuit that you're currently connected to to the SoC you set it to.

Since your relatively new to the scene I would suggest that you're probably putting entirely too much thought into this topic. Most non EV enthusiasts make this seem like it's mission critical when it really isn't. Just plug the car in when you need to and drive it and enjoy it. Spend more time searching these forums for your answers and reading the responses then typing and you'll be much better off with the amount of time you invest on learning about EVs and Tesla specifically.

 

[ucmndd]

There is zero “battery health” reason to artificially slow the charge rate on any level 1 or level 2 EVSE.

 

[Cosmacelf]

200 amps.

I will definitely consider the Tesla charger.

My electric company will give me 500 dollar credit if I purchase a certain charger and charge off peak hours.

I need to figure out what they allow.

So why do you think you’ll be limited to 30A? Most 200A panel setups should allow for a 60A EVSE breaker.

 

[Lasttoy]

I installed two 14.50 outlets on house. Cheap , fast, anyone can use them. I have two portable cables, one in car, one hanging on house. I bought adapter kit in case I visit and need juice from friends house.

 

[SudokuJW]

So why do you think you’ll be limited to 30A? Most 200A panel setups should allow for a 60A EVSE breaker.

My main panel is full. I’d need to get a bigger panel.

The only location I have for a double pole breaker is in a sub panel.

The sun panel itself is fed from a 50 amp breaker in the main.

That’s my limiting factor not my main feed.

I think the 30 amp charger will give me what I need.

18 mph charge will be fine for 90% of my situations.

 

[Cosmacelf]

My main panel is full. I’d need to get a bigger panel.

The only location I have for a double pole breaker is in a sub panel.

The sun panel itself is fed from a 50 amp breaker in the main.

That’s my limiting factor not my main feed.

I think the 30 amp charger will give me what I need.

18 mph charge will be fine for 90% of my situations.

Yes, for most people a 30A breaker is fine.

Which panel is closer to your Tesla, the main or sub? Is your main panel physically full? If so, there might be options like replacing some regular breakers with quad breakers to allow adding more circuits to the panel. Unless that’s already been done!

 

[SudokuJW]

Main and sub are beside each other.
Yea I think the max number of mini breakers have been used.

Maybe I could squeeze a couple more.

The entire 50 amp path just ends up being quite a bit more expensive. I’m not sure I’d ever NEED it.

 

[Cosmacelf]

Whoever installed that 50A sub panel cheapened out! For a side by side expansion sub panel, I’d always install a 100A or 125A breaker for future use. Extra cost is minimal since the feeder length is so short.

Ah well, 30A it is then, and as I said, it’ll be fine.

But when you get your second EV, upgrade that sub panel to 100A or 125A!