61851-1 compatibility question

[Kevin Sharpe]

Ive seen some recent reports from people having problems with some of the Type 2 ("mennekes") Charging Stations that are being deployed in the UK.

I've dug into this a bit and it appears that the behaviour is similar across a number of Charging Stations vendors but one thing that seems consistent is the use of 16A Type 2 to Type 1 cables with a 32A Charging Station.

I've reviewed IEC 61851-1[ed2.0] and it says "The EVSE shall interrupt the current supply if the current capability of the cable is exceeded"

What's the reality on the ground in Europe?

[widodh]

From what I know is that the EVSE 'measures' the capability of the cable and adjust the max current based on that.

What I think you are seeing is that if the EV starts drawing 32A over a 16A cable without the EVSE ever advertising that current. In that case the EVSE should indeed stop delivering current. I know the EV-Box EVSE's do so, they can do either 16A or 32A and have an internal relay which selects the right fuse. They have a C16 and C32 fuse internally.

[Kevin Sharpe]

From what I know is that the EVSE 'measures' the capability of the cable and adjust the max current based on that.

yes, that would be logical and what we've implemented in our protocol controller.

What I think you are seeing is that if the EV starts drawing 32A over a 16A cable without the EVSE ever advertising that current.

not exactly... at least one Charging Station vendor supplies no current if a 16A cable is inserted into a 32A charging station

[widodh]

not exactly... at least one Charging Station vendor supplies no current if a 16A cable is inserted into a 32A charging station

As far as I know that should work.

You plug a 16A cable into a 32A EVSE, the EVSE should see the cable is 'the limit' and adjust the max current to 16A.

It could however be due to safety regulations. The whole circuit would allow for more then 16A, where the limitation is done by software. You could ignore the EVSE signal and draw more then 16A and burn the cable without tripping a fuse.

[dpeilow]

There is a resistor in the plug which denotes the cable's capability. The EVSE measures the value and supplies the corresponding max current.

16A cable in a 32A station should give 16A.

32A cable in a 16A station should give 16A.


Either way the PWM pilot signal should change to indicate to the car that it can only have 16A.

[Kevin Sharpe]

There is a resistor in the plug which denotes the cable's capability. The EVSE measures the value and supplies the corresponding max current.

sure... however, I'm aware of two 32A EVSE that supply no current if the 16A cable is fitted and I think the IEC may want a fail safe that trips if the car asks for more current than the cable can supply.... that's what the EV-Box EVSE's do...

[Kevin Sharpe]

Either way the PWM pilot signal should change to indicate to the car that it can only have 16A.

agreed that's logical and what our DIN PWM signal does. However, in a fault condition it's possible to supply 32A with a 16A cable... maybe that's what the IEC are trying to prevent

[dpeilow]

It's a bad implementation then, because the car should not be able to ask for more if it is getting the correct pilot.

On a car with Mennekes input there is a second failsafe resistor at that end too. J1772 cars don't have it though.

I guess I have all this to look forward to...

[AndrewBissell]

If EVSEs do this then they are breaking the standard. They become useless for most current EVs.

[Eberhard]

yesterday, i got my official Tesla-Mennekes cable. I will do tests next few days.