EVSE current/voltage readout

[jadnashuanh]

FWIW, I just ordered a panel mount volt/ammeter off of Amazon http://www.amazon.com/gp/product/B00K856T70/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 that I plan to hook up in an electrical junction box feeding my EVSE. Cost only $19.99. I expect that I'll just install it in the junction box where the cable from the EVSE connects by cutting the proper sized hole in the cover plate and hooking it to the wiring inside. Have to wait to get it to verify that will work properly.

I may hook up a switch to turn it on/off, depending on how many watts it draws since the car won't be hooked up and charging all that long...but, most of these things only draw a couple of watts, and in the scheme of things, not much. While it doesn't have any recording capability, it is cheap, and should give at least a relative indication of what's going on at any one time, even if it isn't all that accurate. I may be able to calibrate it by hooking up a temporary, higher accuracy device. We'll see how that goes once I get it and install it.

Once I get it and get it installed, I'll let you know how it works out.

 

[jadnashuanh]

Well, it took three different orders to get a unit that worked right! But, finally, I have it all working properly. The meter assemblies themselves all worked, but the current sensing coils on the first two were open, and thus could not read any current passing through. Finally, it's working. But, the car was fully charged when I got it installed. I did turn on preconditioning, and that triggered it. It appears that the current level varies a bit. I'll have more info after the next drive and I need to recharge the vehicle, and that may take a few days.

FWIW, the unit I bought from Amazon is this: http://www.amazon.com/gp/product/B00K856T70/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 but there is at least another source. These guys may have had it pulled since I found the defective coils. I did e-mail that supplier, but they never responded, but might have had a discussion with Amazon. Anyway, the other supplier appears to have the same thing cheaper, too, but I was able to get it faster where I bought it, and the difference wasn't a major factor. It all fits in the electrical box where the supply run connects to the pigtail that was on my EVSE. I just cut a hole in the electrical box cover to mount the meter and also wired in a fuse for the meter and a switch to disconnect it, if I wished. A box extender made it a bit less crowded, but you may get by without one depending on the size box (mine was a 4"x4" square box).

FWIW, that amounts to 6.95Kw instantaneously, near the 7.4Kw max the car can accept.

 

[jadnashuanh]

Two observations: when the car is fully charged and you then send it a pre-condition command, it seems to turn on the EVSE and draws about 12A at 240vac (at least when it was around 40-degrees F).

And, when I got back from a trip this afternoon, and plugged it in, the meter read just under 30A at an ambient temp of around 43-degrees F, (about the max my EVSE can provide). So, no temperature related reduction, at least at the beginning of the charging. I haven't monitored it over time.