wmcbrine
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The New Old EVSE, or, my Folly

Tue Apr 06, 2021 8:07 pm

EVs have been around since the 19th century. Suppose an EVSE were built with the parts / looks of that era, but to J1772 specs? A lot of people would refer to this as "steampunk" (and I'm familiar with the OpenEVSE steampunk contest), but I don't really think of it that way -- not as a combination of modern and old-fashioned, so much as entirely old-fashioned (well, to the extent possible), but compatible with modern cars. For this and other reasons, I wouldn't want to base it on OpenEVSE, but perhaps on AnalogEVSE. (I'd really prefer to build it out of vacuum tubes, etc., but designing such a system is beyond me. Interestingly, one of the few references to AnalogEVSE that I found was a post by the designer on a tube-oriented forum, so apparently he's into that, but didn't do a tube version of the EVSE.)

I picture a wooden box, with analog volt and amp meters, and a set of indicator lights (probably LEDs, but with a classic appearance). For the connector, I envision something almost like a classic telephone receiver, and indeed, I want to hang it from a hook like a classic telephone, which would also serve as a power switch ("on hook" = off).

This EVSE would live in the garage, and I'm not interested in making it a product; but of course, I do want it to be reasonably safe. I wonder about two things: the case, and the power switch. Over on the OpenEVSE forums, there was always concern about the possibility of overheating -- but, rather than use ventilation to keep things cool, they took it to the opposite extreme, trying to make the case airtight so that, in the event of a fire, it would quickly burn itself out. I always thought that was kind of bizarre, but, as I look at other EVSEs, some of them are similar. Is this really a thing -- i.e., to make it airtight to limit fires, and not just as weatherproofing? (I could always do something like a metal box inside the wooden case, but it wouldn't be my first choice.)

As for the power switch (of any kind), that's something I hardly ever see on an EVSE. Why? I get that it could be an extra step, but combining the switch with the handle holder would bypass that. And to me, it seems like the most obvious and effective way to eliminate the vampire draw, and hopefully even to protect the device against power surges when it's off. Am I missing something here?

So... any advice? Am I crazy?

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Nubo
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Re: The New Old EVSE, or, my Folly

Tue Apr 06, 2021 9:39 pm

The essential "tube" if you want to replicate early equipment, would be a mercury rectifier. Only real reason to go down that road, imho.

[youtube]https://www.youtube.com/watch?v=wj9_Elf0OfE[/youtube]
I noticed you're still working with polymers.

LeftieBiker
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Re: The New Old EVSE, or, my Folly

Tue Apr 06, 2021 10:14 pm

My take on Steam Punk is that it is exactly what you are trying to do: building a device to accomplish a modern task, using early Machine Age Technology. As for the electrical fire suppression approach, that was adopted with home and most industrial wiring, with sealed junction boxes. They are designed the way they are precisely to deprive electrical fires of oxygen.
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coulomb
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Re: The New Old EVSE, or, my Folly

Wed Apr 07, 2021 3:29 am

Nubo wrote:
Tue Apr 06, 2021 9:39 pm
The essential "tube" if you want to replicate early equipment, would be a mercury rectifier.
Err, except that a mercury rectifier is, well, a rectifier, and you don't need a rectifier in an EVSE. It would be more useful for DC fast charging. An EVSE is essentially a big switch (relay) controlled by logic, and electronics to generate and check the pilot signal. Alas, tubes are not great at producing +-12V signals, though I suppose that they could do it through a transformer. An audio transformer should be fine, as 1kHz is smack in the middle of the audio spectrum. (The square wave would have plenty of harmonics, though, but 20kHz should be OK). So really, that's where the electronics would be: generating and detecting the pilot signal. The relay could be made authentic as well, as relays go back a long way.

Generating and receiving WiFi signals would be a very extreme challenge, and not all EVSE have/need them, so you'd have to leave that part out. One forgets how much technology is in a small WiFi card these days; it replaces a LOT of radio components and logic! You could probably use smaller relays to sequence through the various stages of the EVSE connection and disconnection. The clicking of the relays as it progresses through the sequences could be a made a feature. They're almost self debugging; you can see where you are in the sequence by which relays are energised. The power supply could be transformer and tube rectifier design; I'm thinking about 60VDC for driving 50V relays from miniature tubes (designed to run on 45-90V). It would be bulky and heavy, but that might not matter for a fixed installation.
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Nubo
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Re: The New Old EVSE, or, my Folly

Wed Apr 07, 2021 12:04 pm

coulomb wrote:
Wed Apr 07, 2021 3:29 am
Nubo wrote:
Tue Apr 06, 2021 9:39 pm
The essential "tube" if you want to replicate early equipment, would be a mercury rectifier.
Err, except that a mercury rectifier is, well, a rectifier, and you don't need a rectifier in an EVSE. It would be more useful for DC fast charging.
Well, of course it produces DC but again I feel that's the only reason to go "steampunk" with any plug-in equipment. Anything else is going to be pedestrian whereas a big mercury rectifier at full song would be glorious.
I noticed you're still working with polymers.

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