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I wouldn’t charge at night in a house with old wiring. 11 kW is a lot of power. Fire risk might be really high.

by lnsru 4y ago

msh 4y ago
Dont 11 kW assume a charger installed by an electrician? Then they would have pulled cable that can handle 11 kW to make a installation. (or maybe I am totally wrong, I am not from the US, in my location I cant install a 11 kW charger by myself legally).
- pwg 4y ago
  > or maybe I am totally wrong For the US, no you are not "totally wrong". The majority of 11kW EV charge ports will have been installed by an electrician and also inspected by the local govt. electrical inspector because the vast majority of people simply do not try do to this work themselves. However, in many locations in the US, homeowners are allowed to do their own electrical installs, provided they pull a permit and have the required inspection performed. Those should also meet code, as otherwise the inspector should have failed the install. Which only leaves those who will do the install without pulling a permit and having an inspection. What percentage of the total those would be I do not know, but given that few do their own electrical work anyway, it is probably a very small percentage of the total. And a sub-set of those would do the install properly to code anyway, even without the permit and inspection.
projektfu 4y ago
Presumably if you install an 11kW (50A circuit) 240V EVSE, you're adding a new breaker to a service panel of at least 150A and going directly to the EVSE with a new cable. The risk of electrical fire would be minimal.
adrianN 4y ago
Why would you charge with 11kW over night?
- msh 4y ago
  I do that because its cheaper to charge over night. I have a 11 kW charger installed on my house.
  - adrianN 4y ago
    If the car is parked for 8h or so at home you can probably charge it with 2kW and still have a full battery in the morning.
    - 988747 4y ago
      Math does not work here: 8h x 2kW = 16kWh. Tesla has 60 or 100 kWh batteries. It only works if you take only short trips (like commuting to work) and never go below 70% of charge.
      - adrianN 4y ago
        It works perfectly fine if you plug in every night in your garage and don't drive more than 100km a day. If your commute is longer you might need 3 or 4kW, but probably not 11kW.
        988747 4y ago
        And if you take a longer weekend trip you'll need the whole next week to catch-up on charging. 11kW seems like necessity - it allows you to charge 0-100% overnight. No advance planning, no compromises required. Also, I'm curious: in my country it is pretty common to have 11.5 kWh installation at home (it was even before advent of electric cars), is the US somehow limited in that regard?
        pandaman 4y ago
        American mains are single (split) phase 240v, your country's are likely 3 phase 240v. Your appliances are likely hooked to 3 phases simultaneously with a 20A breaker so they can get 12kW, American 20A hookup is only good for 4 kW (240x20x0.85 because you cannot draw more than 85% of max power continuously by code).

I wouldn’t charge at night in a house with old wiring. 11 kW is a lot of power. Fire risk might be really high.

by lnsru 4y ago

I wouldn’t charge at night in a house with old wiring. 11 kW is a lot of power. Fire risk might be really high.

msh 4y ago

Dont 11 kW assume a charger installed by an electrician? Then they would have pulled cable that can handle 11 kW to make a installation. (or maybe I am totally wrong, I am not from the US, in my location I cant install a 11 kW charger by myself legally).

pwg 4y ago
> or maybe I am totally wrong For the US, no you are not "totally wrong". The majority of 11kW EV charge ports will have been installed by an electrician and also inspected by the local govt. electrical inspector because the vast majority of people simply do not try do to this work themselves. However, in many locations in the US, homeowners are allowed to do their own electrical installs, provided they pull a permit and have the required inspection performed. Those should also meet code, as otherwise the inspector should have failed the install. Which only leaves those who will do the install without pulling a permit and having an inspection. What percentage of the total those would be I do not know, but given that few do their own electrical work anyway, it is probably a very small percentage of the total. And a sub-set of those would do the install properly to code anyway, even without the permit and inspection.

projektfu 4y ago

Presumably if you install an 11kW (50A circuit) 240V EVSE, you're adding a new breaker to a service panel of at least 150A and going directly to the EVSE with a new cable. The risk of electrical fire would be minimal.

adrianN 4y ago

Why would you charge with 11kW over night?

msh 4y ago
I do that because its cheaper to charge over night. I have a 11 kW charger installed on my house.
- adrianN 4y ago
  If the car is parked for 8h or so at home you can probably charge it with 2kW and still have a full battery in the morning.
  - 988747 4y ago
    Math does not work here: 8h x 2kW = 16kWh. Tesla has 60 or 100 kWh batteries. It only works if you take only short trips (like commuting to work) and never go below 70% of charge.
    - adrianN 4y ago
      It works perfectly fine if you plug in every night in your garage and don't drive more than 100km a day. If your commute is longer you might need 3 or 4kW, but probably not 11kW.
      - 988747 4y ago
        And if you take a longer weekend trip you'll need the whole next week to catch-up on charging. 11kW seems like necessity - it allows you to charge 0-100% overnight. No advance planning, no compromises required. Also, I'm curious: in my country it is pretty common to have 11.5 kWh installation at home (it was even before advent of electric cars), is the US somehow limited in that regard?
        pandaman 4y ago
        American mains are single (split) phase 240v, your country's are likely 3 phase 240v. Your appliances are likely hooked to 3 phases simultaneously with a 20A breaker so they can get 12kW, American 20A hookup is only good for 4 kW (240x20x0.85 because you cannot draw more than 85% of max power continuously by code).