My intent with this design is to make a small, simple, portable level 2 charger out of a level 1 charger that can still function as a level 1 charger. I also want it to be fully automated using the EVSE as the control unit, relays, and a GFCI.

Note if you have the 2013, 2014,2015 EVSE You are on the wrong page take a look athttps://www.instructables.com/id/313CONVERTING-A-20...


You will be working with a 220V circuit. All parts used should have a minimum rating greater than or equal to 15AMP and 220VAC. I TAKE NO RESPONSIBILITY FOR YOU ELECTROCUTING YOURSELF. If you don't have experience with High Voltage/High Current you may not want to do this.  If you do not wire this circuit as it is in the diagram you can damage your car and house and yourself. NEVER WORK ON A HOT (PLUGED IN) CIRCUIT! Do research beyond this article before you start. I take no responsibility for you or your car or any property that may be damaged.  You are responsible for wiring things properly! If you do not know how to work safely, and how to wire things in reference to a schematic do not attempt this.


NOTE: I did this a long time ago and did not get pictures so these are a recreation. Drill a small hole in the cork, thread a cork screw in and pull out the cork. Then take out the 6, T20 Torx head screws out and pop the case apart.


Printing this page may be helpful.


Three feet of SJOOW 12/4 wire ($1.49 a foot) totaling:                            $  4.47
     (If you are using an extension cord you might want
     to get a length of wire, so that you will no longer
     need to use an extension cord.)
Box of 12-10 gauge ring crimp connectors :                                             $  3.39
Box of 12-10 Gauge crimp connector caps nylon close end :                   $  3.89
NEMA 14-50 plug (standard in newer homes and RV parks):                   $10.95

Total :                                                                                                        $22.70


Remove ground wire screw and ground wire from the AC wire inside the casing. Leave the ground wire that goes out to the J1772 in place.


Remove the AC 110V screw and wire from the AC wiring block.


Remove the black foam tape from the choke coil (It peels apart with a little work), then remove the choke coil and keep it. I used a small knife blade to pry the latches open (do not force it, it only takes a little push). Next, remove the screws holding the 110V AC in cord in place and pull cord out.


Measure out the length of wire that needs to have its outer layer of insulation removed. Wrap a piece of tape around it as a stop. Use a box cutter to cut back about 1 inch of the insulation. Since you are going to cut off about 7 inches of the red and the black wire, make that cut over them. That way if one of them gets nicked it is the part that is getting cut off anyway. After that first little cut, grab onto the wires and pull them against the slit you started - a little like peeling a banana. This way the insulation on the individual wires does not get nicked.


Run the 12/4 cluster of wires back thru the grommet in the side of the case. It will be tight so I recommend using a little wire pulling lube, but a drop of liquid soap will work too.  Use the securing plate and screws to lock it into place.

For crimping use a ratcheting crimper.

To strip a multi strand wire use a stripping tool one gage larger than the wire. For example 12AWG multi strand wire strips with a 10AWG striper.  The number on a stripping tool is for solid wire, multi strand wire is one gage larger.

If some of the strands are cut off when stripping, cut then all off and start over.

Cut the green wire to length, strip the end, attach a crimp connector ring and connect it to ground. There should be 2 wires connected here: the new ground and the ground that runs to the car.

Cut the black wire to length, strip the end, attach a crimp connector ring and connect it to where the 110V black wire used to connect.

Cut the red wire to length, strip the end, attach a crimp connector ring and connect it to where the 110V white wire uses to connect.

Do not plug it in yet.


Put the choke coil back on the green wire. Put the foam tape back on the choke coil. The choke coil gets rid of noise and that’s good.


Cut the white wires (first panel) that come out of the circuit board that go to the transformer and strip the tip. Then cut the white wire coming in from the NEMA 14-50 to a matching length (second panel) and strip the tip. Next crimp them together and crimp the open wire. Note the hot black wire coming in feeds the other white wire that goes to the transformer.  My preference is for this configuration where the transformer is wired to black and white wires, the standard configuration.

Do not plug it in yet, but we are almost there.


This unit comes with a varistor (round thing next to silver bar)(it is taged on step 6) that is designed to protect an 110v circuit and will act like a dead short if connected to a 220V circuit, so IT HAS TO BE REMOVED. My wire clippers are too large to get into that small space and the black rubber stopped me from unsoldering it, so I grabbed it with a pair of needle nose plies and bent it back and forth a couple of times until it snapped off. This is not my preferred approach, but it works.Note: if I were going to try this again I think I would take a pair of small angle wire cutters and grind the site's down so that I could get in that tight space and clip off the wires on the varistor.

Close the case and put the screws back in.

The plug is just a normal NEMA 14-50 plug, so follow the directions that come with it.

I then added two 140V maximum operating voltage varistor (this is what is routinely used for a 110V circuit)(The number on the varistor following the “K” should be 140)to the plug across hot (red) - return (white) and hot (black) - return (white). This protects both the 110V and 220V circuits.

Close the plug and put the screws back in.

Plug it in.

Step 13: 120V ADAPTOR

Warning: This adaptor is only for this unit and should not be used for anything else. The NEMA 14-50 receptacle is wired so that what the NEMA 14-50 plug is plugged in the black goes to black, white goes to red AND white, and green goes to green. The 110v plug is a standard 110V plug with black hot, white return, and green ground.


This is probably the end of the up-grading the EVSE projects. I could make it put out more power (amps) but I do not think that would be safe. I could try some three wire 220V configurations; 220V to 20V transformer - extra cost and work, voltage regulate 220V to 110V - extra cost, work and watts, use the ground as a return - Dangerous illegal wiring.   None of these are  as good as what I’ve done: the 110V/20V side of the circuit is run off 110V/20V and the 220V is handled by relays capable of handling 220V and the circuit is built for 12AMPS.

So what’s next, maybe a charger from scratch, who knows?

If you have any questions please ask.

Thanks, Dave.

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104 Discussions

Hi Dave thanks for this instructable! I already have a upgraded charging cable that has an L6-R30 plug. If you can, would you tell me how to make an extension cord for my cable? I am getting confused when I shop for the L6-R30 plug and connector that gives directions to use a 5 wire or 3 wire 16/3 SJ. Then seeing that the charging cable uses a 10AWG... I always think putting something like this together would be easy to figure out... the I get stumped by all the conflicting designations.

So I know this thread is old but I think I messed up. So I did this conversion last night and when I plugged my charger in, POP - smoke, and tripped both my plug breaker and the sub breaker. Reread the instructions and realized I missed step 12 (remove the varistor). My question: can I just remove it now or did I screw the whole thing up by applying 220V to it?

1 more answer

Your fine :-) The Varistor did what it was made to do and killed itself tripping your breakers. Remove it and add a new one for 220v.

So I know this thread is old but I think I messed up. So I did this conversion last night and when I plugged my charger in, POP - smoke, and tripped both my plug breaker and the sub breaker. Reread the instructions and realized I missed step 12 (remove the varistor). My question: can I just remove it now or did I screw the whole thing up by applying 220V to it?

Hi Dave, Great instructable. Was wondering if you (Or anyone else who has done this) would be willing to do this upgrade on my charger? I am very mechanically inclined but electrical is a different story. Im a little hesitant tearing into my expensive Nissan charger, especially since its the only one I have lol. If you or someone who has successfully completed this upgrade is willing to take a look I would ofcourse compensate them accordingly. If you or anyone is interested please feel free to contact me: m2robins at Hotmail dot com

2 replies

There's a professional service to do the upgrade http://evseupgrade.com/ .
I am not associated with the guy (though he lives in the same town as I do). You can try this for repair also: chances are whatever is blown in your unit will be fixed by the upgrade.

EVSE Repair.png

1 year ago

I have now converted two chargers from 2011 Leaf but decided to make it multi-voltage, so it looks unchanged and I can still plug it into 110V outlet with the original plug, but it can also be fed 240V for fast charging. All I did was removing the 110V varistor and replace the transformer with a small 15V DC switching power supply. I found out by varying the voltage that a minimum 15V DC is needed for the pilot signal to work reliably. The charger will work on 12VDC but my Leaf refuses the signal (too low voltage on the pilot signal). I noticed that the relays cycle an extra time as if to go to fail-safe, but everything works great both at 110 and 240V. I still use the original NAME 5-15 plug so it looks original after swapping the transformer to the supply.

hi, I made this. it was working great, but now my 110V to 20V transformer is blow out. where I can find this part?

10 replies

I just googled 110V to 20V transformer and there is a million of them.

But if you blew the transformer you probably did something wrong. send some pictures and I try to see if I can see the problem. try measuring the input voltage to the transformer at the site where this happened.

If you are only going to use this for 220V then get a 220V to 20V transformer and hock it to the 220V.

Thanks Dave

thanks dave for reply. ones I made it, it was working fine for couple of months. then it stop it. I need to replace 110V to 20V transformer.


Send me send some pictures of the modifications you made.

Thanks Dave

Here is picture. I brought this one with modifications.



Who did the modifications?

They are not the modifications from my instructable. Nor do they look like quality work.

Have you checked output off that voltage regulater?

Thanks Dave

I bought like this. It was working on 110 and 220.

It is not a bad idea but poorly executed. I should have some time this weekend to play around with it. could you send me a picture of the cord end and a tight shout of the varistor(see the little box on step 6 of this instructable)..

Thanks Dave


Sorry I have not had a chance to mess around with this. you might look at some of the laptop power supplies some of them have 20v power supplies.

Thanks Dave

FYI there's a professional option also: http://evseupgrade.com/
They'll upgrade your unit for automatic switching use (works on either 120V or 240V depending on what you plug into).