I've been following this thread from the beginning and have a few questions about your mod that I haven't seen answered, although I might have missed them:
1) You've more or less said that you consider the exact details of what you replace in the EVSE to be a trade secret, but I'm hoping you could provide a little more info without getting into the trade secrets. Is it correct that you replace the 12V transformer with a switching power supply (like a computer uses)? You also mentioned you replace a handful of other components that aren't rated for 240V. Are these basic circuit elements like resistors, capacitors, etc., or is there more to it?
2) Your mod involves partially depotting the circuit board inside the EVSE. Do you repot the board afterwards, or does the water resistance of the modified EVSE depend entirely on the outer shell of the case? Or do I misunderstand the reason the original circuit board was potted?
3) You mentioned that the OEM EVSE does not implement part of the J1772 spec, a "diode test". What is that and does your modified EVSE implement it?
4) One customer provided you with an EVSE without the plastic plugs in the bottom covering the screws holding the outer shell together. The returned EVSE had these screws covered with hot-melt glue. Was this a special endeavor to ensure the water resistance of the outer shell without the plastic plugs, or is this something you do to all your mods to make opening the modified EVSE more difficult?
1. There is no 12v transformer in the original EVSE. Because we don't condone or recommend non-qualified individuals attempting modification of their EVSE, we do not wish to encourage this, so details are intentionally not published. It requires a non-trivial time investment to properly develop and test such an upgrade. We concluded there is no valid reason to publish details, except to encourage DIY efforts, which could get people and/or property hurt. Given the amount of overhead involved in this work, we are offering the upgrade at a bargain. Thus, there really should be not be much motivation to attempt the modification yourself, unless you really know what you are doing, in which case you shouldn't be asking me for help! :-p
2. Yes, we are very careful about resealing everything. Everything is re-sealed with a top-grade GE silicone rated for high thermal conductivity and dielectric strength. The original design is potted for weather resistance, and we believe our upgrade preserves or even betters this protection.
3. The SAE J1772 specification wants the EVSE to distinguish between a low resistance pilot short (such as could be incurred in a puddle of salty/dirty water) and an actual vehicle, so they set up the vehicle end to include a diode, and the Pilot signal was designed to be able to detect whether the diode is present or not. This wasn't implemented (likely due to extra complexity) in most EVSE's I've tested, including this Panasonic unit, and the AV unit Nissan recommends. I too believe the "diode check" is overkill and unnecessary, the GFCI will take care of low resistance shorts, thus the EVSE design is adequately safe. We don't modify any of the core design elements of the EVSE, it's Pilot generation/detection circuity and logic, or the basic safety circuitry, so we do not change this lack of diode detection function.
4. Because the original EVSE design had hard rubber plugs sealing the screw holes, we found it prudent to preserve this seal. Because extraction of the original plugs leaves them in a condition that would degrade their sealing performance, we upgrade the seal with a special high-density sealant that adheres to the plastic to form a hermetic seal. Opening the EVSE voids our warranty, and since us opening the EVSE voids the factory warranty, you are left without a warranty if you unseal the unit. If you are comfortable without a warranty, then of course, you are free to do whatever you like.