Start a new topic

Wh counter accurate?

Hi all, 

I'm hoping someone with more knowledge than I on the inner-workings of the device may be able to help me with a question. This question involves the current and watt-hour counter on the OpenEVSE.

Given W = V x I, does the controller simply multiply the observed amperage by a fixed value for voltage (i.e. 240), and apply the result against a given period of time to display the running total for watt-hours passed through the unit?

The reason I ask is this: I figure this should work (roughly) if voltage is always close to 240; however, on a 3-phase service (where the device is supplied by phase 1 and phase 2), the device would only receive somewhere in the vicinity of 208 volts. In this scenario, if voltage is hard-coded, I would guess the watts calculation would be off (too high).


Does the device measure voltage in real time to compensate for this?

1 Comment

You are correct, the Current is multiplied by a fixed value.

If you are building a Level 2 Charging Station you could modify L1 default value to detect L2 single phase (208v) and keep L2 split phase at (240v).

The AC detect chips would work correctly as 208v is a single hot plus neutral and Split phase would be two hots.

Login or Signup to post a comment