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Electrical Vehicle Chargers - No Diversity?

Apostolos

Good afternoon

I have a question to address to more experienced engineers in here about the load calculations around EVCs

Its clearly stated in BS7671 that no diversity should be applied to an EVC

This is a bit weird to me as to the ramifications it has

So, assuming we have a TPN 32A EVC, this means you cant apply diversity and feed it with a 20A MCB. It should always be a 32A MCB

All good

What happens in case you have a DB feeding 5 off these chargers?

Assuming you do not have a load management facility between the 5 chargers, does the 'no diversity' mean I have to assume a DB charged with 5 x 32 = 160A load????

And protect it with 160A, and install a cable for 160A etc etc etc?

Is this what no diversity means for the EVCs?

Always assuming you do not have a load management system installed in the EVCs

Thanks

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    As others have stated without a load management system then you have to assume diversity is 1. However there are options with a load management system which will help. One of them being a static load management system which regulates and distributes energy evenly and in real time between all connected vehicles, so as not to exceed the general static setpoint for the vehicle loads. This method allows you to evenly distribute available energy between all vehicles that are being charged. So if you had a bank of say 5 x 7.2kw chargers and only 3 vehicles were plugged in, depending on what the static set point is then it's possible all 3 could receive the full 7.2kw. Also once a car is fully charged then power will be diverted to another charger. 

    There are 2 others to consider but wont go into detail here and they are:

    Dynamic load management and Artificial intelligence-based load management. 

    If you wanted to use a smaller MCB like a 20amp then you will need to make sure the charger is configured properly, but by doing so you will reduce the kw output and get a slower charge. You can set them as low as 12amp. 

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  • 0

    As others have stated without a load management system then you have to assume diversity is 1. However there are options with a load management system which will help. One of them being a static load management system which regulates and distributes energy evenly and in real time between all connected vehicles, so as not to exceed the general static setpoint for the vehicle loads. This method allows you to evenly distribute available energy between all vehicles that are being charged. So if you had a bank of say 5 x 7.2kw chargers and only 3 vehicles were plugged in, depending on what the static set point is then it's possible all 3 could receive the full 7.2kw. Also once a car is fully charged then power will be diverted to another charger. 

    There are 2 others to consider but wont go into detail here and they are:

    Dynamic load management and Artificial intelligence-based load management. 

    If you wanted to use a smaller MCB like a 20amp then you will need to make sure the charger is configured properly, but by doing so you will reduce the kw output and get a slower charge. You can set them as low as 12amp. 

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