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I believe there are other domestic EVSEs that support load-sharing as you describe. Me, I'd be tempted to add another project to my already long pipeline-of-interesting-but-somewhat-stalled gadets. I'd stick 2 Mainpine + Arduino combos into 2 32A Rolecs, and intercept the CP line into the Arduino. Said Arduino would talk, wirelessly maybe, to the other one, and probably also to one monitoring house solar exports. Between then they'd fake the CP signals, adjusting the mark-space ratios so the total current offered didn't exceed 32A. I'd add a current sensor to the mains going into each car, so that when one of them starts reducing the charge current (tapering, or just at the normal end and only doing a bit of BMS balancing stuff) then obviously the offered current would reduce to 6A to that EVSE, allowing the other to have more. And you can add whatever rules about operator 0verriding these priorities etc etc. Just a SMOP, really!
(Small Matter Of Programming) :)
My son would be drafted in to knock-up an app to talk to this stuff, and Robert's your avuncular relative! Over to you...
 

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For 6mA DC fault current sensing the newer Pod Points use a benvac 4641-X900 differential current sensor. With it you can use a cheaper type A RCD rather than the dearer type B.

 

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could i ask a question of everybody. can i connect a variable resistor to my podpoint 7kw charger to vary the charge going to my leaf instead of switching the small dil switches on the board.
 

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Without knowing any details of the board, it's dodgy at best. If that DIL switch simply selects 1-of-several resisitors, it might work to change to a variable resistor. But it may simply be signalling a single number into a microprocessor, in which case this number will be interpreted by code inside the cpu, and you can't get at that. There's also the possibility that the cpu may inspect this DIL value (resistance or number, whatever) at start-of-charge time, and may never re-examine it during a charge, as it knows the rate you want to use. So you might need to restart the charge after making a change.

Firstly you'll need to trace where the DIL switch connections go, and see if there's a load of resistors downstream, or what. May not be an easy task...
 

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Without knowing any details of the board, it's dodgy at best. If that DIL switch simply selects 1-of-several resisitors, it might work to change to a variable resistor. But it may simply be signalling a single number into a microprocessor, in which case this number will be interpreted by code inside the cpu, and you can't get at that. There's also the possibility that the cpu may inspect this DIL value (resistance or number, whatever) at start-of-charge time, and may never re-examine it during a charge, as it knows the rate you want to use. So you might need to restart the charge after making a change.

Firstly you'll need to trace where the DIL switch connections go, and see if there's a load of resistors downstream, or what. May not be an easy task...
Yes thanks Andy. It looks like it's the latter, withthe connections going into a CPU chip. Not a simple resistor series network. I was really asking where to connect the pot. But I see it's not that simple. I thought maybe one of the existing connections available on the board could be used, with the dip switches set at the max of 7kw. Ah well, thanks for your thoughts.
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You'd use a pot to change the resistance of the resistor in the plug, surely? That won't go below 13 Amps though.

I would just solder some leads to that dip switch, and have another switch indoors.
 

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The resistor in the plug is purely there so the EVSE can make sure you don't overload the charge cable. You don't get fine control. The 3 settings of these which are relevent to us are for 13, 20, and 32A cable. The 20A cable gets used in the 3.3kW (16A) wall EVSEs, and I expect the 13 gets used in granny chargers. Not much scope there for playing around!

If you're serious about tweaking this EVSE to get fine control, you're going to have to intercept the CP line where it goes into the car-cable, stick an Arduino/similar in here & fake the signals on a new CP line. Doable, but non-trivial.How finely can you set the current with the dips?
 

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Those value look to me exactly like the cable-resistor settings. In which case, it's very unlikely that the cpu will pay any attention to them once it's started a charge. Why should it?
And just make sure you don't accidentally select the 32A number, if your EVSE is only 16A! Plug an EV in that takes >16A and you'll start melting cables.
 

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I currently use my homemade charger using the mainpine controller and a contractor where I have a pot co nected into the mainpine unit. This is variable from 6kw down to 1.4kw and have this podpoint spare. Because it goes to 7kw I thought there were connection on the board to allow me to vary the charge as I can do now, I have PV installed hence the varying of charge. I use an arduino to vary this resistance into the mainpine depending on spare PV power, so charge costs me nothing. Just trying to use the podpoint unit as its relays are a lot quieter than my contractor which makes a very loud clunk when switching the charge on/off.
 

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Hager & probably others make "Silent Contactors". You pay for the quiet!
Hager-Esc440s-Silent Contactor, 40a, 4no, 230 V
looks suitable, but I'm not a sparky so take professional advice!
 
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