120v to 240v EVSE Modification

[redpoint5]

I posted this in another forum, but since I have high regard for the bright people here, I'd like to get input from here too.

I purchased a used Leaf EVSE for $200 and have been L1 charging with it ever since (I charge a Prius Plug-in, not Leaf). A couple things I don't like about L1 charging is the charge efficiency, which I've measured at about 70%, and the length of time it takes to charge when multiple trips are made close together.

This Instructables article talks about how to modify a Leaf EVSE to use a 240v outlet and output L2 power. Since I already have a 240v line in my house and the few items I need to make the modification, I'll likely tackle this project.

I now have the original Prius charger, and I'm wondering where the info is to modify the Prius EVSE to allow for L2 charging? Searching the web and this forum so far has not turned up any results.

I see many posts endorsing sending the unit in to Phil's company for the upgrade, but that rubs me wrong in 3 ways. The first is that I bought the EVSE for $200, and spending $260 on a simple upgrade that involves very few parts seems silly. Next, I prefer to be a tinkerer than a consumer. Learning and doing is both more fun, and cheaper. Finally, I don't like Phil's attitude on the other forum I won't mention. He's not interested in educating people; only selling his product. I get that, and I can't blame him for promoting his business; I might do the same in his shoes. However, I participate in forums to both be educated and to educate others. If I can learn something and then pass along the knowledge, I will. Open source FTW!

If someone can point me in the right direction for completing this mod for the Prius EVSE, I'll do a good write-up with pictures and possibly put together a Youtube video.

A small bunch of wealthy hippies isn't going to put any meaningful dent in our fossil fuel usage. Eliminating the price penalty for going electric is the only way for the masses to convert.

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[MPaulHolmes]

Gosh I wish I knew. I don't know anything about the prius.

[P-hack]

(3.0)CONVERTING A LEAF LEVEL 1 (12AMP) CHARGER TO A LEVEL 2 (12AMP) CHARGER

There is a way to make an adapter to run it on 120 also when appropriate, this mod is only good for 4 prong 240 fyi (basically move one transformer lead to neutral so it still sees 120v). You could take your chances tying it to ground, but the author strongly discourages that, but if I had a 3 prong 240 without update access i would be strongly tempted.

Also there is a video of someone somewhere using two extension chords on two outlets that are on different 120v legs to get 240. So if you are in an apartment or renting you might have 240 access and not know it. And can cobble together a 4 prong 240 outlet where it is convenient.

Check that your charger can handle both 120 and 240 of course.

And careful with the varistor selection (see comments), they probably aren't critical to the function, but might save you $200 if you get a surge.

[oil pan 4]

I have 275 volt MOVs I will sell cheap.
$5, free shipping to the U.S. at least.
I know they work I have put them inside my welding machine on the input side and they have not blown.

[Piotrsko]

If you do the different wall plug trick MAKE SURE they aren't 10 amp lighting circuits because your GFCI circuits won't protect you

[P-hack]

while it isn't critical, they do discuss using 2x 130/140v AC varistors to keep protection while on 120v.

[P-hack]

think I'll give this a shot now that the juicebox is acting up.

[P-hack]

got some 130v varistors off ebay, the 12/4 SJOOW (only thing that will fit the grommet) cable wasn't at any of the home improvement stores, SOOW is too thick, so I got a few feet of that off ebay as well. Since my current charging demands are in the 3kw range, I may hardwire it to an outlet. I suppose I could just put the whole thing in an electrical box on the wall and not worry about the grommets too.

[redpoint5]

I'm contemplating how I'll supply the 240v to the EVSE once I upgrade it. I have an unused 240v dryer outlet in the wash room just on the other side of wall to the garage. There is also an unused 240v 12-2 wg line that goes to a living room. I could easily pull the line to the outlet and route it into the ceiling above the garage. Finally, I'm wondering if I should install an 8 awg 50 amp circuit to future-proof the home.

I still need to get the varistors and see about upgrading my leaf EVSE.

[P-hack]

go for the 8awg The future might be here before you know it.