MG5 variable charge rate

[jhinshel]

I have an EVSE with a viridian EVSE Protocol Controller (EPC). I was able to match my PV generation with the charge rate on my nissan leaf by adjusting the resistance between the IC pin and ground. The resistance on the IC pin cause the EPC to adjust the control pilot (CP) signal to the vehicle. the vehicle adjusts the charge rate accordingly. This does not work the same on my MG5.
Has anyone got experience of dynamically changing the charge rate of the MG5 on a type 2 EVSE?
I am wondering if it may be possible to adjust the resistance between the proximity pilot (PP) and ground but I suspect that this may just set the charging power for the charging session and will not be adjustable in the session.

 

[Jomarkh]

I would have thought that it would work in the same way, when you use a granny EVSE it must have a resistor to tell the car only to pull 2.2kW.

 

[jhinshel]

the proximity pilot PP connection does this via a resistor to earth. trouble is I don't think this can be used to adjust the charge rate of the car dynamically. i.e. the charge rate is probably set based on the resistor reading at the start of the charge session. Does anyone know if this rate can change over the course of a session?

 

[BugEyed]

I have a pre-facelift MG5 and am on Intelligent Octopus using a Type 2 to Type 2 Ohme lead. This varies the charge rate regularly throughout charging both suspending the charge and varying the rate. I'd assume that it uses the same technique but don't know for sure, but can confirm that it works.

 

[jhinshel]

bugeyed, what make and type of charger (EVSE) do you use for charging?

 

[Jomarkh]

bugeyed, what make and type of charger (EVSE) do you use for charging?

He says in his post that he has a type 2 to type 2 Ohme.
The easiest way to get IO is with an Ohme.

 

[BugEyed]

Strictly my EVSE is a ProjectEV/Growatt one but it is in "dumb" mode, all of the control is done by the old style Ohme lead sitting in the middle following instructions from Octopus via Ohme.
Personally I haven't gone for an Ohme charge point as they don't fully support solar, which the ProjectEV/Growatt one does when switched into the appropriate mode. Currently only Ohme supports Intelligent Octopus unless you have a supported car (not MG) although allegedly MyEnergi/Zappi are working on it.

 

[greentangerine]

My OpenEVSE charger is able to vary charge based on house load and/or solar surplus but that is done internally to the unit - I know that because it has a tethered cable and the resistance to indicate it can take 32A is hardwired at the car/plug end - there is no PP wire back to the charger.

 

[jhinshel]

greentangerine - which vehicle do you have? did you build your open evse charger? if so, is the variable charging signalled via the CP pole in the plug?

 

[greentangerine]

greentangerine - which vehicle do you have? did you build your open evse charger? if so, is the variable charging signalled via the CP pole in the plug?

I did build the kit - very easy. They do a pre-assembled one as well though.

There is no CP back to the charger as the resistor is just hardwired in the plug to indicate that the supplied cable can handle 32A so the car can try and draw that but the control of charge is done in the unit itself and you can limit to a specific value, on house load (to avoid blowing the incoming fuse if you have other stuff like heatpumps etc), restrict to solar excess etc etc.

It does have OCPP support but not yet on the Octopus IO supported list yet unfortunately.

 

[jhinshel]

greentangerine - the open evse schematic shows a CP connection to the vehicle but no PP. A hardwired resistor can be included in the plug for the PP terminal to indicate the cable limit. Is this your set-up?

If so, did you wire a 220 ohm resistor from the plug PP terminal to earth?

I have this setup with a viridian controller that used to work with the nissan leaf but does not work with the MG5.

bugeyed - can you let me know a little more information about your "old style Ohme lead"?

 

[greentangerine]

greentangerine - the open evse schematic shows a CP connection to the vehicle but no PP. A hardwired resistor can be included in the plug for the PP terminal to indicate the cable limit. Is this your set-up?

If so, did you wire a 220 ohm resistor from the plug PP terminal to earth?

I have this setup with a viridian controller that used to work with the nissan leaf but does not work with the MG5.

Sorry, confused with CP/PP.

The original cable already came with the appropriate resistor for 32A installed in the plug, as did a replacement bought from elsewhere after a rodent chewed through the original.

I very much doubt the MG5 ignores the resistance else it'd melt cables that can only carry 16A etc.

More likely it notes it can take whatever the cable physically indicates at the start of the charge but in my case, what it requests isn't necessarily what it gets!

 

[jhinshel]

greentangerine - to clarify, your system uses the CP connection to via your open evse charger to vary the rate of charge to the car. What range of charge rates does it achieve? i.e. 2kw-6.6kw for example? Please can you state what the minimum rate of charge that is achieved and if this varies in steps or continuously up to the maximum?

 

[greentangerine]

greentangerine - to clarify, your system uses the CP connection to via your open evse charger to vary the rate of charge to the car. What range of charge rates does it achieve? i.e. 2kw-6.6kw for example? Please can you state what the minimum rate of charge that is achieved and if this varies in steps or continuously up to the maximum?

See OpenEVSE

Minimum settable is 6A, max 32A for my unit. The car can seemingly take lower than 6A when balancing etc. Mine has a tethered cable and there is no wire from the unit to the plug for proximity - just a resistor in the plug from PP to ground with the correct value for 32A.