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Discussion Starter · #1 ·
Those wishing to change the plug on the EVSE that GM provided might ought to know that it comes with a thermistor molded into the head of the 120v plug. Cutting it off is fine, the unit will operate normally. Those who wish to change the plug to a different type and keep the temperature sensing can install a small off the shelf 1kohm thermistor in the new plug. For example, if you swap the 120v 15amp plug for a 240v 15amp flat bladed plug, you might wish to continue to have the temperature sense ability.

The beauty of having an EVSE with a 240v plug is that the adapter you make to carry around to get 120v to that plug isn't going to hurt anything... ie plugging a 240v device into 120v isn't going to harm anything. But we are "forced" to carry around an adapter that takes 240v into a 120v plug and have to label it so it is not used for anything except our car. Wiring the EVSE with a 240v plug also makes it much easier to find off the shelf adapters to go from 240v15a to say, a 14-50. Maybe I'm trying to solve a problem that doesn't exist for many?

The spec on the thermistor is 1k at 25C, and a ß=3800K . For example this listing on ebay. https://www.ebay.com/itm/10-x-1K-OH...m=321044251218&_trksid=p2047675.c100011.m1850

In the plug lead you'll find Black White and Green wires, as well as a red (themistor ground) and orange (thermistor in). The red and orange will connect to the thermistor.

It would be really slick if we could figure out a 5 pin plug to use as a standardized adapter base... and be able to make adapter ends that carry the red and orange wires all the way through to the plug. We might even be able to get away with a 4 wire plug since the red thermistor wire and the earth ground are common.
 

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Nice work on figuring out the specs of the stock GM EVSE temperature sensor. It is too retain that safety feature that I favor the 240 to 120V adapter for the stock EVSE instead of sending it off to have the plug changed or having the user change it themselves.

I wonder if clippercreek, the OEM for the stock GM PCBA, or some other EVSE manufacturer, has the same safety feature and an intermediate multi terminal plug?
 

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Discussion Starter · #3 ·
Nice work on figuring out the specs of the stock GM EVSE temperature sensor. It is too retain that safety feature that I favor the 240 to 120V adapter for the stock EVSE instead of sending it off to have the plug changed or having the user change it themselves.

I wonder if clippercreek, the OEM for the stock GM PCBA, or some other EVSE manufacturer, has the same safety feature and an intermediate multi terminal plug?
Now there's an idea! I'm off to the clipper creek website to see if they have a stumpy cord for 220v with the temp sensor molded in!! never thought of that!
 

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It would be really slick if we could figure out a 5 pin plug to use as a standardized adapter base... and be able to make adapter ends that carry the red and orange wires all the way through to the plug. We might even be able to get away with a 4 wire plug since the red thermistor wire and the earth ground are common.
I think if you're set on ditching the plug, this is really what you want. The trick is finding the right off-beat plug combination to use.

If there is any plug that really needs a thermistor, it's the 120 volt NEMA 5-15 plug since that might be plugging into old wiring that isn't rated for a 12 amp draw. If you're plugging into a 30A dryer outlet and only drawing 12A, it's probably not going to be much chance of it overheating.

(I went the route of the NEMA 5-15 socket to NEMA 14-30/50. That way I don't void the warranty on the EVSE and if I ever need to have it replaced, or to help out a fellow Bolt owner, my investment is in an adapter, not my current (emergency/in-the-trunk) EVSE.)
 

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Thanks for this. I bought a ClipperCreek Gen2 control board with no enclosure or cables. It appears to be a GM spare with the same microcontroller programming and glued through-hole components, unlike my AmazingE unit with the exact same PCB (programmed with no temperature sensor). With this info I can either replicate the original function or bypass it with a 1k Ω resistor to use this control board in my ultra-budget EVSE build. Thanks! :)
 

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Sweet! Welcome to the forum. Let us know how it turns out.
Thanks. I’ve been updating this IMGUR album as I piece it together:

So far I’ve only spent about $30 on the electronics, $50 on the J1772 plug+cable, $20 on an enclosure, and a few dollars for the appliance cord, wire nuts, etc. I’m having trouble finding the scrap piece of 10-3 Romex electrical wiring I had around so I might just wait for the enclosure after all. Guess I should go ahead and order some cable glands.

The other day I had the idea to get a second control board to turn it into a dual unit pedestal for future use. Unfortunately the seller had finally sold out of the control boards. :(
 
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