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A project log for J1772 Hydra

Charge two electric vehicles at once

nick-sayerNick Sayer 12/16/2018 at 17:160 Comments

When we last left off, I had promised some updates, but never really delivered them. The problem that had put me off the project was the problem of the ground continuity monitor sensitivity, but in conversations with others in the OpenEVSE project, it seems that I was making the problem harder than it had to be. The 100 ohms per volt value from the spec that I had used as a target isn't the sensitivity of the GCM, it's the minimum impedance between either power conductor and ground (which is a spec we easily meet since the only path to ground from either conductor starts with a 150k flame proof resistor). So I could probably even slightly reduce the sensitivity of the GCM to make up for the temperature sensitivity that otherwise is shown by the optoisolators.

I have the EVSE logic/display board sitting on my bench to build and have the AC board in at OSHPark. The schematics and board files have been updated to match these versions. I'll update the log when that's done.

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