Thanks for sharing, it is great that there is this element out there. But the pricing is out of this world. For a kit, I put together, regardless how refined the kit is .... I expect it to end up being half the price of a commercial unit. It needs to come down a full $100 and I would buy it.
This is like the old joke about the washing machine repair man charging $500 to fix a washer by screwing in a screw. Itemized price: Screw - $0.05, knowing where to put the screw - $499.95.
The OpenEVSE folks have taken the time to source the parts, design the cases, designing producing, populating, and programming the control boards, package everything up, and ship to the point where assembling the kit is little more than snapping and screwing a few pieces together. It's really less a kit and more a disasembled product like furniture from Ikea.
The Open Sourced parts of the product is organized such that there is enough information and code out there that you don't need to buy the kit. You can source the parts. You can wire up the controller. You can program it. You can figure out how to house the unit. You can choose the amperage of the J1772 cable. In short you can invest your time recreating everything the kit builders have done for you. You'll save much more than $100 in the process. But it'll take a ton more time, reconfiguration, and testing to get the unit you want.
I'm taking this route. One because I'm really in no hurry. Second is that working on stuff like this is a hobby for me. So my invested time and lack of need are really considered of little value as to the enjoyment I get from tinkering with a project and getting it working. Here's a brief description:
- My goal is to have a wifi accessible/controllable unit. I'm building this by pairing a Raspberry Pi Zero W controller for the wireless and web interfaces to an Arduino Pro mini for the low level controller functions. The pair of these can be purchased from Microcenter for example for a total less than $10.
- Support circuitry includes the triple voltage power supply (-12/5/12V), which must accept both 120 and 240V AC input, J1772 Control Pilot generation and detection, contactor activators, voltage detection, and GFCI detection. The first three are the bare minimum to get the car to charge. All of them are required for safe operation of the unit.
- A standard 220VAC contactor is in order. My plan is to activate the contactor with a 220V Solid State Relay. In fact I'll test at low power with the SSR itself as it's rated up to 25 amps. So 12 amps @ 120V isn't going to stress it.
- I have acquired a 30A J1772 handle with 16 feet of 8 gauge cord. It's a steal at $95.
The contactor ($10-20), support circuitry ($30 including the SSR), Controllers ($10 total), power supply ($15), and J1772 cable ($95) adds up to under $200 in parts. But then the support hardware and controllers have to be wired, the controllers have to be programmed, and all of it has to be mounted into a sturdy, water resistant/proof, enclosure.
Given the above description, the kit prices are not really out of line. I do find personally that the professional units in the $500-600 range to be exhorbitant, as they are build from essentially the same parts listed above with at least a 3x markup.