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Hello All,
Thank you for letting me join your Forum. I currently have a BMW i3 94Ah BEV and have a Rolec 32A wall charger installed.

My wife has just swapped her Discovery Sport in for a .. BMW i3 94Ah REV, will be collecting it in a couple of days time. I understand that we can get have another wall charger installed and receive the Gov grant.

Is there some 'fancy pants' cleverness that can be done to 'share the load' if the two cars are plugged in at the same time? The house has a 100A main fuse (don't fancy blowing that puppy) and I guess both cars at once would munch up 64A thus leaving 32A (ish) for the rest of the house. Is there a box of tricks that can 'split the load' ie. 16A & 16A if both cars are plugged in or does it depend on the setting in the i3?
 

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The Zappi charger can do this I believe. It can throttle the second car according to how much power the first charger is using.
The Zappi can indeed load balance. As it measures grid usage, you can give it a maximum grid use figure. If there's a danger of going over this, it reduces the available charge to the car. This is exactly what I have.
 

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Just put both cars on reduced load in the settings menu, but the ChargePoint Home chargers are set out of the box at 16amp even if you have a 32amp fuse like I have for the charger.

I have two chargepoints but you have to be careful.
 

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Just a suggestion ... If you have socket outlets then you can buy two 16A-rated leads. The leads also contain a resistor in to limit the charge rate. Just using 'the right' lead for the occasion may be a 'dumb' alternative, but I think you are right to worry a little about pulling 64A PLUS the domestic load through a standard domestic outlet.
 

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Just a suggestion ... If you have socket outlets then you can buy two 16A-rated leads. The leads also contain a resistor in to limit the charge rate. Just using 'the right' lead for the occasion may be a 'dumb' alternative, but I think you are right to worry a little about pulling 64A PLUS the domestic load through a standard domestic outlet.
That’s true Donald but why bother when they can just change the setting on the car. EV cables aren’t cheap.
 

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That’s true Donald but why bother when they can just change the setting on the car. EV cables aren’t cheap.
I agree. It was just an alternative to the above better suggestions. ;) (Not all cars have load limiting so if someone had the same question for different cars and happened by this thread, there it is.. another idea..)
 

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I agree. It was just an alternative to the above better suggestions. ;) (Not all cars have load limiting so if someone had the same question for different cars and happened by this thread, there it is.. another idea..)
Good point (y)
 

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A second charge point has to be capable of preventing the overload - the installer has to inform the DNO of the installation, provide details of their load calculations (maximum potential supply load using allowed diversity), and explain/seek approval for the measures to be used to protect the supply from overload.

Using an intelligent charger like Zappi is one method. Relying on the home owner to use settings in the car or lead will not be acceptable, as this cannot guarantee ongoing management of the load (what if someone uses the 32A cables instead of 16A, plugs in a different car without charge rate limiting etc).

I’m about to have a Zappi installed on Thursday as my second 32A chargepoint (I already have a 32A basic Rolec), and have waited nearly 3 months to get the required DNO approval! My installer has been great, constantly chasing the DNO to finally get the required paperwork. In my case the DNO have asked for the rate limit in Zappi to be set at 80A although my supply/main fuse is actually 100A.

In future I might upgrade my original unit to a Zappi too as that allows both chargers to rate-limit if/when required so both cars get equal service (rather than one being allowed full 32A charging while the other always gets limited if the maximum supply capacity is at risk of being breached).
 

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Or you can buy a 16A charge contoller for your Rolec box and swap it in, leaving you with the option to change it back in the future. I even have one available!
 
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