It's been a while since this project has had some love given to it. Recently I brought the Hydra up to date, and this project will benefit from that.

The power boards (versions 1.2) are still state-of-the-art, but the logic board has had some improvements made:

• The MC34063 -12 inverter supply has been replaced with a charge pump, which is much simpler.
• The 5 volt supply is now made from an AP1509, which, again, is much simpler
• The pilot generator now uses a pair of SOT23-6 complimentary MOSFET pairs, which is the same design now as the Hydra.

I intend to upload the new board files and add PDF schematics for all of them shortly.

The one aspect of the design that's somewhat less than satisfactory is the voltmeter. The optoisolator transfer function is very heavily influenced by temperature. In freezing temperatures I've seen L1 readings of about 140V, which is a 16% error. It is good enough to tell the difference between L1 and L2, at least.

Anyway, despite being a slightly older design, my current "portable" EVSE is an OpenEVSE II design that has been operating successfully for years. The OpenEVSE project has advanced from where this design was, and I'm not sure how many of its current features would work (likely those that are based on i2c peripherals or connections to the serial port would work ok), but I'm still proud of this design.