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Charge like you Volt-to: DIY J1772

16792 Views 2 Replies 2 Participants Last post by  bruceme
I have a dirty secret, I like free stuff and I think you do too. Lately I find myself charged on public charging. No, I technically rarely "have-to" use the thin boxes popping up all over town. I've had facility folks come over twice now to tell me, "Those spaces aren't open!" I fluff my feathers and point to my charging cord and extort... "Oh yes I am, and I have a card to prove it". Yes, I carry my card with pride and I'm not afraid to tell those gasaholics a thing or two!

Until recently I relegated myself to the basement of the two story out-house of charging; 120V! At 1.6wk, that ment 2hrs to charge a typical 20mi trip-leg. So for all the glory of free charging, it just got my charger begging to suck on that lovely 220V/30A hiding behind a fancy gas nozzle look-alike. Who is that fooling anyway?

I've had a hard time bellying up to the bar of SAE and pulling out my anty in the J1772 game. For all practical purposes it serves the same purpose as a NEMA L6-30 and costs 5x more. But if you want to play the game, you gotta pay the man. So I splurged and spent the $110 on one for my birthday.

It arrived yesterday (Friday) and I spent this morning wiring up my adapter. I started by chopping off 12" from my home 220v system (plug and all). I use heavy duty 3 x 6ga rubberized cable. The J1772 I have came with solder lug/pins (one end is a lug, the other is the pin). I tin'd the lugs with a small torch, stripped the wire leads and tin'd them so they wouldn't spread in the lug. I made a splice wire for the ground lug (used for the signal line, I'll talk about that in a minute). I placed all the spacers and parts together so I wouldn't have to do anything twice. I torched the lugs again and dipped the leads into them... NOTE: Pin 3 (Ground) is a different sized pin. I didn't realize this and spent 10 minutes unsoldering/resoldering. This all went together in about an hour.

After that I did the research on the sense line. If you want all the benefits of this great and robust power standard, google other projects, I skipped all those subtleties and got'r'done! Here's how you can do it too.

Pin 4 is a +/- 12v PWM signal. If you pull that pin down to +6v, the charger will fire up. So I wired in a 50v diode with a resistor to ground (remember that extra lead). Technically the SAE specification calls for 890 ohms, but that radio store was out of 890 ohms and 1k-ohm appears to do the trick. I took the car to the nearest charging station and tested it at full power today. It says I pulled 3.51 kw :D

Pin 4 ----->|--------[1k-ohm]------- Pin 3 (Ground)

So with a little wire, some basic skills and one stupidly expensive receptacle, you can build a J1772 to NEMA L6-30R adapter for yourself.

Drive however you want, but charge safe!



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Discussion Starter · #3 ·
Manzanita PFC 30, no buck enhance. It's good for 3.51kw max (if it's cool). 100F it drops to about 2kw. I want to build my own 1kA re-volt + 10kw EMW charger/controller/BMS combo.
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