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Hi Guys,

so I started to look around for a charge/wallbox option at home, many models on the market, some suited for solar panels, some with or without badge , etc.
Yesterday a friend of mine, who used to own a tesla, told me he just had a 400V(380) plug connected to this 400V(380) circuit, without a wallbox or similar in between and had his tesla hook up to that directly. I even did not know this was possible. I am not a specialist in this field, who can tell me if this is a valid (low cost) option, or plain stupid because of ... ? Thanks


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Isn’t there a simple protocol for requesting and acknowledging power from the charger? The millisecond that the link is broken with the car, the outlet is supposed to switch off. I would strongly advise to use a charging box, whether it is technically necessary or not. A charging box is essentially a switched power outlet with necessary safety functions.
 

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Good idea

The i4 comes with the flexible fast charger. You can buy a red adapter CEE for the flexible fast charger.

You would need a Wallbox if you want NFC for authentication, for using it with PV and so on.

 

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I'm not sure that you "can" use this solution in Belgium. I mean you should have your installation certified after adding the outlet (or even a wallbox, but there is a specific "light" procedure for this) and I'm not sure that they will accept the usage of this outlet for a car. I know that it's not authorized in France for exemple. Obviously no one will come bother you if you decide to do it, but you could get some trouble with your insurance in case of any electric issue after the installation.
 

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I'm wondering if it will come with a 14-50 or 6-50 connector for here in North America?
 

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I'm wondering if it will come with a 14-50 or 6-50 connector for here in North America?
„The maximum power of 9.6kW is only attainable when equipped with the correct adapter (NEMA 14-50 or NEMA 6-50) on a 240V outlet.“

 

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I requested the 400v 32a adapter to be delivered with my car, so I can directly connect the “flexible fast charger” to my in house wall connector. It should deliver 11kw of power.
A wall box is only needed (in my opinion) if the connector is publicly accessible, to prevent others to start charging on your costs.

Off course, a wall box looks nicer, and is easier to use since it manages your cables and you don’t have the separate charger black box laying around.

On a side note: the standard red 400v plugs are actually not rated to work at their maximum capacity for many hours at once, that’s why I chose the 32A connection, since the 16A would be closer to maximum. 400V 16A is about 11KW. 400V 32A will only be used for +\- 50%.

More info here: (article in Dutch) https://blog.widodh.nl/2013/11/waarom-een-type-2-laadstation-en-geen-rode-cee-voor-een-model-s/
 

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My wallbox is some wood I had kicking around, and some black paint. Hehe
.
.

I requested the 400v 32a adapter to be delivered with my car, so I can directly connect the “flexible fast charger” to my in house wall connector. It should deliver 11kw of power.
A wall box is only needed (in my opinion) if the connector is publicly accessible, to prevent others to start charging on your costs.

Off course, a wall box looks nicer, and is easier to use since it manages your cables and you don’t have the separate charger black box laying around.

On a side note: the standard red 400v plugs are actually not rated to work at their maximum capacity for many hours at once, that’s why I chose the 32A connection, since the 16A would be closer to maximum. 400V 16A is about 11KW. 400V 32A will only be used for +\- 50%.

More info here: (article in Dutch) https://blog.widodh.nl/2013/11/waarom-een-type-2-laadstation-en-geen-rode-cee-voor-een-model-s/
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Discussion Starter · #11 ·

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Hi Guys,

so I started to look around for a charge/wallbox option at home, many models on the market, some suited for solar panels, some with or without badge , etc.
Yesterday a friend of mine, who used to own a tesla, told me he just had a 400V(380) plug connected to this 400V(380) circuit, without a wallbox or similar in between and had his tesla hook up to that directly. I even did not know this was possible. I am not a specialist in this field, who can tell me if this is a valid (low cost) option, or plain stupid because of ... ? Thanks


View attachment 2597
Normally in the charging cable there are also 2 wires that are used for communication between the car and the wallbox.
At the very least you will lose some features/options and who knows maybe even some security mechansimes
 

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Hi Guys,

so I started to look around for a charge/wallbox option at home, many models on the market, some suited for solar panels, some with or without badge , etc.
Yesterday a friend of mine, who used to own a tesla, told me he just had a 400V(380) plug connected to this 400V(380) circuit, without a wallbox or similar in between and had his tesla hook up to that directly. I even did not know this was possible. I am not a specialist in this field, who can tell me if this is a valid (low cost) option, or plain stupid because of ... ? Thanks
@Hans_L , the technical guru of this forum is @aigarius, referencing him for help.

From what I know though, there is only 2 ways to charge an EV:
- AC charging through the charging circuit that all EVs have, that is usually limited to 11kW, some countries may get 20kW on tri-phased; if you exceed the capabilities of that charger, you'll just fry it. So I would go to the BMW website of your country, look under BMW Electric and Charging, they should provide you the details of what they are capable under AC charging.

- DC charging that bypasses that charging circuits and goes straight to the battery, designed to take 400V plus DC at high current, but subject to a complex protocol based on a control pin for the car to tell the charger how much voltage and current it wants. Without a proper DC charger box capable of handling the communication protocol, you won't even get the car to connect its DC connectors due to the potential damage to the battery.
 

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I'm not an electrical engineer, I work with automation, but I'll give an explanation a go. All of this is based on Norwegian regulations, which are very thorough and safe.

What you want to achieve:
  • Charge your car as fast as possible
  • Avoid damage to your car due to external factors
  • Avoid electric shock to people
  • Avoid fire hazards
Charge your car as fast as possible
For one-phase connections (standard AC home-system) the maximum current is 32A, giving 7.4kW. There is one phase that connects to the neutral.
For three-phase connections (what is normally in the network itself, and is sometimes led to your power meter), the maximum current is still 32A and you get 400V between the phases. This is a TN network, Terra Neutral for the frenchies.
You may want to have a fuse in your fusebox that is 40A in order for it not to trip on the sustained 32A load. If you electronically limit your charger to 32A (which is the maximum anyway), this should be fine, and you don't need to dimension wiring for 40A.

Avoid damage to your car due to external factors
You need a surge protector. Check that this is installed already in your fuse box. It must be a type that is designed to withstand lightning strikes.
You need an residual-current device that measures the current leak to ground. If you have a type B RCD in the charger itself, it will trip on very small currents, if there is any problem with your car or charging cable.

Avoid electric shock to people
You may want an additional RCD in your fuse box. This can be omitted if you use a double-insulated cable, and the cable is not run in any closed walls.
If say a load is applied between ground and the phase (like a human), it's nice to know that the circuit will break after a very short time.

Avoid fire hazards
If your cable is only installed in open-air cableways, you may get away with only using 6mm^2 wire, providing it's double insulated. If it's in confined walls, the lack of heat dissipation means you must go bigger. Also, the energy dissipated to heat due to the conservative cable size is energy you are paying for, so it's worth considering going up a notch.

Installation instructions and installation norms must be followed to the letter for this kind of installation. Loose connections are one of the most common causes of fires, and here you are sending high currents unattended! Do not do this yourself unless you are authorized to do so.

Additional considerations are load balancing and smart charge timing. Nord Pool pricing is always available, so a smart charger can plan your charging for when it's the most inexpensive. Very relevant with recent pricing. It should also be able to integrate into a load balancer. Then you can use a higher current for your electric car, even if your home network intake fuse might only be 63A. It can limit the amount of power sent to the charger if the total load nears the maximum.
The best charger on the market is Easee, it offers all of the above, RFID charging lock, smallest footprint and more. It has a whole host of security functions, such as temperature sensors on all connectors and lifetime 4G connection for free.


Oh yes and there are some simple "power management system" commands between the charger and car that must take place. Like, ready to transmit, ready to receive, maximum current. It's actually quite clever, the phases and null will connect first, but the pilot and connection pins are deeply recessed, so it will be physically impossible to get a GO to the car unless the power connectors are deeply seated.

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When you charge your car on public charger or wall box there is always a communication between them.
My name is Beemer I4 and you?
I am Technove wall box, nice to meet you! What can I do for you?
Well I am low of juice and would like to get some for more range for my owner, are you in shape?
Yep I feel great 😊
Good to know, how much speed power can you give me?
Well I can go up to 11kwh, it's my maximum, will it be OK for you?
A little slow but I am not stress for now I'll stay here all night long so it will be OK
Good so can I start to send you the power now?
Yes go ahead I am ready, than you.

The End 😍
 
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