# OpenEVSE build



## dougingraham (Jul 26, 2011)

Thanks for the report. I considered one of these but insurers are funny about things permanently wired to your house that are not UL certified so I decided the saving in this area was not worth it.

What kinds of things does it show on the display?


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## frodus (Apr 12, 2008)

I'm a UL trained Panel Builder.... so that helped  . All the Components (minus the board) are UL listed. The board design and software seems pretty solid. Two relays makes it such that if one welds, the other can (hopefully) open.

Works pretty well so far, but I've had limited chance to charge with it.

While charging, it will shoe:
EVSE Available Current
L1/L2 status
Time stamp
Charge duration

It will also display faults if present.


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## dougingraham (Jul 26, 2011)

frodus said:


> I'm a UL trained Panel Builder.... so that helped  . All the Components (minus the board) are UL listed.


Your build looks really clean from the photos.



frodus said:


> While charging, it will shoe:
> Commanded Current
> L1/L2 status
> Time stamp
> ...


My understanding is that with J1772 the EVSE tells the charger what it is capable of and it is the chargers responsibility to not try to exceed that. So is the line for commanded current the number the EVSE is telling the charger or is it the measured current the charger is pulling?

Thanks!


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## frodus (Apr 12, 2008)

Thanks! I thought the build out before I assembled everything and got the right parts before I started.

I guess I should say "EVSE Available Current", because yes, the EVSE tells the charger what it can draw. There is no actual current sensing in the OpenEVSE, other than for the GFCI CT.


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## remy_martian (Feb 4, 2019)

An interesting homebrew Arduino-based EVSE here, discussing the design process, linking references, and sharing the firmware & hardware on Github:









Electric Vehicle EV Charger


Electric Vehicle EV Charger: I built my own 7.2kW EV charger and fitted it inside a Zappi enclosure. The 2 aims were simplicity and safety. This article documents the build. I wrote the Arduino software for it and all design files, software and part lists are available on the G…




www.instructables.com


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