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.
<p>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.</p>
<p>hi, I made this. it was working great, but now my 110V to 20V transformer is blow out. where I can find this part?</p>
I just googled 110V to 20V transformer and there is a million of them. <br><br>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.<br><br>If you are only going to use this for 220V then get a 220V to 20V transformer and hock it to the 220V.<br><br>Thanks Dave
<p>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. </p>
<p>Send me send some pictures of the modifications you made.</p><p>Thanks Dave</p>
<p>Here is picture. I brought this one with modifications.</p>
<p>Yuck! Terrible soldering. Not a good upgrade.</p>
<p>hi.</p><p>Who did the modifications?</p><p>They are not the modifications from my instructable. Nor do they look like quality work.</p><p>Have you checked output off that voltage regulater? </p><p>Thanks Dave</p>
<p>I bought like this. It was working on 110 and 220. </p>
<p>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)..</p><p>Thanks Dave</p><p></p>
<p>Hi</p><p>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.</p><p>Thanks Dave </p>
<p>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</p>
<p>There's a professional service to do the upgrade <a href="http://evseupgrade.com/" rel="nofollow">http://evseupgrade.com/</a> .<br>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.</p>
<p>FYI there's a professional option also: <a href="http://evseupgrade.com/" rel="nofollow">http://evseupgrade.com/</a><br>They'll upgrade your unit for automatic switching use (works on either 120V or 240V depending on what you plug into).</p>
<p>Thanks, I used the central idea here to make a different repair.<br>(The central idea above is not all that clear in the text: basically it comes down to having two separate power feeds for the 110V and 220V sides of the device).<br><br>In my case the EVSE had already been upgraded by http://evseupgrade.com/ , but had become water damaged. I was able to hack in an external 110V to 9V transformer, and get it working again. See picture. Thanks.</p>
<p>I also have the 2013 leaf charger but decided to take a crack at it anyways. One main difference is that inside the ac connector there is a component Im not familiar with that has 2 wires running down to the control board. it has a resistance of 29.4k ohms (thought it was a resistor) and the evse will not operate without its two wire connector plugged in( fault light flashes after 5 seconds, no charging) It looks like a capacitor but with a glass bulb at the tip of it instead of a ceramic disc. Its located inside of the sealed 110v connector located between the line and neutral pins but not connected to them. On the control board line voltage runs through the circuit. The connector is labeled fdr-10t. Not sure if you can enlighten me on this issue, any help is appreciated. Thanks. I uploaded some photos they are in this order. The component I broke :( the connector on the board, the whole control board, the end of the 110 harness with line, neutral, ground and that connector, and last is the dissected 110 plug that the component was mounted in.</p>
<p>Hi Dave, Magnus is right: it is a temperature dependent resistor. Mine is 21k at room temp and after a few minutes in the freezer, the resistance reads 26k Ohm. So I am sure that if the plug heats up, its resistance will drop and the EVSE will cut power. Besides my measurement data, there is also a simple reason why this device can't be an FDR: For accurate frequency response, the frequency must be measured very carefully. How can a device that is *not* connected to the AC wires, but insulated in a glass body, measure the AC frequency? I am sure that the EVSE processor is doing the FDR, by using its crystal to run an accurate clock and measuring the incoming AC periods very accurately and modulating the pilot signal to match any deviation from the nominal frequency (60 Hz in USA). This functionality will be *unaffected* by soldering a resistor of about 22k across the pins where the yellow wires were, since that will just tell the EVSE that the plug is always at room temp - obviously now you need to take care of not overloading the plug and keeping contacts clean. Or get yourself another NTC to replace the one in the plug! Hope this helps, Cor.</p>
<p>Hi! That thing is a little bugger that detects if the plug heats up due to the load and faulty and worn out outlets. It will then abort the charging (or lower the amperage) if the plug gets to hot. You can replace that device with a simple resistor. </p>
<p>Hi.</p><p>I&rsquo;m not 100% sure but I believe it is a frequency dependent <br>switching device. Frequency dependent switching devices are tools that will <br>shut off the charger if the grid is under excessive load. It is a way of <br>protecting the grid. I&rsquo;m not sure why they put it in the plug and not the EVSE, <br>it may be a way of isolating it from the noise of the EVSE. </p><p>I&rsquo;ll include a link that goes into more detail on frequency <br>dependent switching devices.</p><p>http://webhotel2.tut.fi/units/set/research/inca-public/tiedostot/Kansainvaliset_julkaisut/Rautiainen_SGM_EV_Charging.pdf</p><p>I have not yet tried to upgrade one of the 2013 Chargers. <br>From what you&rsquo;ve shown me I might just leave the plug intact and run an extra <br>wire out of the EVSE. I&rsquo;ll try to get a hold of one and see what I can do. </p><p>Thank you for sharing your experience, I wish I could be of <br>more help.</p><p> Thanks Dave. </p>
<p>I used an old stove cord with molded head instead of buying a plug and wire combo. I installed the MOVs inside the charger as shown in pictures. Works great. Used 2 MOVs of 150 volt.</p>
<p>When it was 110 volt version it had a steady Green Ready Light. I did the conversion and now it has a slow FLASHING green light. Scared to plug it in to the car. Anybody have any ideas?</p>
<p>ok, going to answer my own question. bad or no ground and you get a flashing ready light. connect to a socket with good ground and you get a solid light.</p>
<p>Does anybody have a part number or where to get the 140 volt MOV's</p>
<p>Hi. This is a great walkthrough. Is there a way to get to the 16A 240v charging level with this homebrew method? This will be similar to the EVSE upgrade option offered by evseupgrade.com</p>
<p>TheThere are a Hundred easy ways to trick the car into pulling<br>more amps. Any of the programmable microprocessors and a few lines of code, a<br>555 or even an eight track recorder. These are not high security devices. It easy<br>to trick them. But I would never recommend over amping any product, I think it<br>is an unsafe practice.</p><p>On a side note I&rsquo;ve seen on forums where people have paid<br>for modifications to their charger. And then tested with an amp clap and they<br>got far less than 16 amps.</p><p>If you do not feel that this is something that you can, do<br>not have someone modify your charger if they want to charge you the same amount<br>as a new level 2 16 Amp charger would be. You can buy a new level 2 16 Amp<br>charger for what they are charge to modify one. Buy a new one and keep you old<br>one as a spare or sell it. The cost of paying someone to modify a product<br>should not equal the cost of buying one that has the feathers that you want and<br>if it does buy the new one.</p>
Can I use 2 275VAC rated varistors instead? I have these already out of a server power supply.
If you want to have it as a dedicated 220v device then yes. String one across the 220v circuit. <br><br>Thanks Dave
<p>Hi, Do you have a schematic or block diagram that shows the modifications - before and after as that is easier to see what the instructions actually change and how they work. I could try and work one out myself but you must have something after having worked out where the varistors were wired relative to the relays and GFCI relays on each side? </p><p>thanks</p>
<p><em><u>if you have the 2013, 2014,2015 EVSE try </u></em><a href="https://www.instructables.com/id/313CONVERTING-A-2013-LEAF-LEVEL-1-12AMP-CHARGER-TO/" rel="nofollow">https://www.instructables.com/id/313CONVERTING-A-20...</a></p><p>it hasschematic's. there are not exactly the same but they will help. </p>
Could I use a 10-30 plug or would I be better off building it this way and using an adapter? The only available outlet I have is a 10-30.
<p>What might be easier and better would be to add a 110v cord and run the controller transformer off of it and feed the 220v through the relay. look at the(3.13) it has better schematic's.</p><p>Thanks Dave </p>
<p>Lots of people ask this question. I'll have to build one out some day. </p><p>The easiest thing would be to replace the 110v to 20v transformer with a 220v to 20v transfer and just use the 3 existing wires. Keep the polarity off the transformer to ground the same. Then it would be a dedicated 220v charger. And you will still need to pull the varistor. If this doesn't make sense to you don't do it.</p><p>I still think the better option is to upgrade the house wiring to the 14-50.</p><p>If you you do it let, me know who it go's. take pitchers and post.</p><p>Thanks Dave</p>
Hi I bought a Nissan Leaf 2013 from Japan. The charger has a Japanese type of plug. But we have British type plug. Can I connect a UK plug by cutting the exiting plug. But I found 5 wires in this wire. 2 mains, 1 earth and 2 yellow wires. Where to connect these 2 yellow wires. Please help to overcome this issue
<p>There is a safety feature in the plug see post from 2 years ago form <a href="https://www.instructables.com/member/jdufresne" rel="nofollow">jdufresne</a>. </p>Also look the instructables I made for the 2013 it covers this. <a href="https://www.instructables.com/id/313CONVERTING-A-2013-LEAF-LEVEL-1-12AMP-CHARGER-TO/" rel="nofollow"> https://www.instructables.com/id/313CONVERTING-A-2...</a><p>I'm not familiar with non-US wiring. There is probably off the shelf adapter. </p><p>Thanks Dave</p>
<p>I'm preparing to follow this instructable but I am wondering why the 120v - 20.9A transformer is needing to remain at all since the transformer is being fed to the white wire from the NEMA. <br>What purpose is the transformer serving? <br>Is it just required because of the safeties built into the circuit board?<br>I don't see how it would function when attached to a 110v power source if the input is coming from the molex connector and then feeding to the return of the NEMA.</p>
<p>The control circuit runs at 20V. The transformer converts 110v to 20v.</p>
<p>Hi Dave, </p><p>Your idea is excellent. <br>I might have a project lined up for you. How can I get in touch with<br>you?</p><p>Ranmal</p>
Also, just for those who don't know ohms law, this is a 2.8kw charge cable, at 120v. Approx. charge time for my 2011 leaf is now 8 hours from fully drained, instead of 14. Cudos to you Dave.
Great diy! I own a 2011 Nissan leaf. And this is saving me time and money! Now how about boosting range? ?
<p>Hi Dave,</p><p>I figured it out.</p><p>Forgot to hook up red to white on 110v jumper.</p><p>Thanks again for this knowledge. I learned allot,</p><p>Kevin</p>
<p>Hi Dave,</p><p>Thanks for this instruct able.</p><p>I did the conversion to my 2011 EVSE.</p><p>Get a green ready light when I plug it into power, but when I plug the J1772 into the car I get a steady red fault light also and no power is passed on to the car.</p><p>Any ideas?</p><p>Kevin</p>
<p>I have seen Your solution for the amarican 220V charging Device. (4 wires)</p><p>I hope may bee You could solve a way to do it for the European 220V. (3 wires)</p><p>Earth and two wires With 220 - 240V. May bee the only solution is to change the transformer (110V / 20.5V) Do You know if there is one 220V/20,5V With the same wires who can replace the 110V version? I have an amarican LEAF and the original Charge Device I can not use without changinging it for 220V.</p>
<p>You could use a step down transformer. 220V to 110V one of the $10 tourist one will work fine. Then run both of the 110V to 20V(cut both white wires) transformer wires to the 110V side of the 220V to 110V transformer. So there is NO connection between the 110V and the rest of the circuit. The 110V ONLY connects to the 110V side of the 110V to 20V transformer. </p><p>Thanks Dave</p>
<p>Hello Dave will this work with the 2015 leaf . Thank you</p>
<p>No. But the 3.13 will. See other things I've made.</p><p>Thanks Dave</p>
<p>Love this simple conversion! every Leaf driver should do this, makes a world of difference when you have access to 220v at work. I had some trouble working out which wire to cut coming from the transformer because the pics are so low res, I added a few of my own in case others are having similar problems. I had no trouble locating 120v varistors, 5 dollars on ebay and I got 2 dozen. I used a 20a generator plug though, thats what I already had on hand (female wall, male plugs)</p>
<p>scratch that, 130VAC metal oxide varistors instead of 120vac, they are old but unused so maybe not 140vac your recommending, tested against 220v which is good enough in my book</p>
Dave, figured out uploading. Here are some images of Varistor, packing slip and inside of EVSE plug.

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