OpenEVSE 3 phase

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(Vinay Jakkal) #1

How to use the contactor relay for 3 phase 440 v supply using the Open EVSE kit

(Robert Wall) #3

Is this thread any help?

(Glyn Hudson) #4

Yes, the OpenEVSE can be used with a 3-phase contactor

  • Connect the openevse controller between L1 > N (240V)
  • Connect L1-L3 + N through the GFCI CT
  • Connect L1-L3 + N through the 3-phase contactor
  • Connect the power CT to L1

The OpenEVSE current reading will measure the current in one of the phases. You would need to modify the
display to correctly calculate the kWh supplied.

See photo of a 3-phase openevse setup:

Three phase contactor can be purchased from:


(Vinay Jakkal) #5

Thanks Sir

Just one question what is the actually use of 3 phase input if we are
connecting the controller between single phase only …!!

Vinay Jakkal

(Glyn Hudson) #6

The three-phases will be used to charge the EV e.g 16A 3-phase = 11.5kW, 32A 3-phase = 22kW. Obviously the EV will need to be able to support 3-phase charging e.g. BMW i3, Tesla.

(Yoav Levy) #7

How accurate the current readings will be if we measured only one phase?

(Glyn Hudson) #8

When charging an EV the thee-phases will be balanced i.e the on-board charger will draw the same current from each phase, therefore the measurement will be accurate. Although if billing grade energy reading is required It would be best to also install a 3-phase utility meter inline.

(Yoav Levy) #9

Thank you!

    I'm working on a new controller board based on openEvse.

    The board will only support an alternating current relay and will be suitable for mode 3 installations.

    Do you think that three current sensor circuit one for each phases  will be a good solution?

    I need an billing grade energy reading.

(Glyn Hudson) #10

Yes, if you have available inputs on your controller board I would recomend adding the option for 3 x CT inputs. Also a AC voltage monitoring circuit would be a good addition to monitor the AC voltage.

(Yoav Levy) #11

True, maybe i can use the relay sense input line.