My L1 ESVE findings.....

[jwallace3]

I am not trying to reinvent the wheel or anyting. Ingineer has a great product. I am just posting results of my own mod that is inexpensive for those who are wanting to try it themselves. To build one from scratch costs less than $50 for the electronics and such, the connector is the main cost. I don't plan on using my modified ESVE for long for portable charging,it is just a quick fix for my current needs and maybe others would have this same need for a quick $20 fix to get 240V 12 amp charging with their current unit.

My 240/120 universal portable unit I'm helping develop with the university is basically a good exercise for aspiring engineers in school to design something based on a specification that is standard based. The result should be a relatively inexpensive portable charger based on the J1772 standard. The standard actually doesn't call for portable L2 charging ESVE at all. L2 according to the standard is dedicated. So any portable L1/L2 universal type charger deviates from the standard, but will still abide by the standard and be completely compatible. There may be cost competitive units available on Ebay or wherever else, but if all engineers just sat around and said somebody else already did it, we wouldn't have anything new. Improvement is what we are striving for and like I said, it's an exercise for young engineers in school. The outcome should be exciting. With the standard and a few relays, resistors,diodes and a micro, I can build one from scratch with some assembly code building.

The $20 dollar fix is for those who need a quick, portable option that's cheap and easy to perform. It involves changing out the pigtail and running 2 jumpers. Quick and easy. Not a good permanent solution, but for some, it may meet their imediate needs. Details to come with pics. It's about a 20 minute operation for those that are interested.

I expect our university design to be about half the size of the panasonic unit. The first generation will just have 4 LEDs for indication, but I plan on adding a small screen and some buttons for navigation and control. I want to add metering functionality so that if you are at a friends house or even at work and want to re-imburse that person(s) for some reason you can enter their KWhr rate and get a cost for your charge at that location. Not for everybody, but I think it would be neat and the students are very excited about it. I have 2 of the best in the program to guide in the development of this device.

[jwallace3]

Everything is rated for 250VAC, just not the electronics that support it. If you de-pot the board it can never go back to panasonic for warranty work. Using my method, theoretically you could remove the jumpers and pigtail and send it back as it was originallly manufactured. like I said, this is a quick fix, not a permanent one. Ingineer has a good product, I'm not trying to replace it. This is a fix for those who don't have the time for all the sending and receiving of units and just needs 240 portable charging now.

Yes, the firmware upgrade takes some off the top but gives it back to you at the bottom end int the form of a hidden "reserve". When you get low and it says you've got about 8 miles left, it's really more like 15.

As for temperature of the modified EVSE, Ingineer's done fairly extensive torture testing at significantly higher than 16a. It doesn't get much hotter than that. Lots of us have done it, you'll be fine.

I'm no electrical engineer, but this talk of jumpering things seems strange. Ingineer actually depotted the entire board and found it was all ready for 240v except for a couple components that were rated at 120v. How can you do this without replacing those components or running them way over spec (which doesn't seem safe)? Anyhow, you're free to do whatever you want with your own unit, of course.

[Volusiano]

So I'm hearing a couple of things here that I'd like to expand on:

1. The OP said that all components inside are rated at 250V AC. I'm hearing that Phil has to depot the board to replace a couple of under-rated components (the 2 relays?). But then in another thread, chris1howell said that those relays are rated at 240V 20A and are not replaced as a response to garygid and darkstar saying that the relays are replace. So I'm a bit confused here. Did Phil have to replace any potted components or not? If not, then why were there talk of Phil having to depot the circuit board, which is why his upgrade is expensive, due to the depotting/repotting labor?

2. The OP said your jumper approach bypasses a few of the safety features. Can you elaborate on what safety feature(s) were bypassed exactly? How important are they? And what are the risks of bypassing them?

3. I also heard that Phil replaced the transformer with a universal dc power supply that can accept either 120V or 240V. So how does a jumper cable allow the unit to automagically accept 240V input?

4. The OP keeps saying that his solution is a temporary solution and not a permanent solution. But then he said he could charge from 3 bars to 12 bars with the jumper approach just fine. So why is it a temporary solution only? What are the drawbacks?

[TonyWilliams]

I heartily support your efforts and encourage you to let your vision guide you.

You never know where your inspiration may lead!

[Volusiano]

There is one safety feature that I'm not sure how it can be implemented at 240. The panasonic ESVE checks to see if ground and neutral are tied together to tell the unit that the circuit is properly grounded. At 120 the existing cable has hot, neutral, and ground. If you look at any 240 charger there is still only 3 wires hot 1, hot 2, and ground. So if you modify the panasonic ESVE for 240 charging there is absolutely no way with 3 wires that this feature can be implemented because the charger would be checking to see if the previous neutral terminal (now hot/phase 2) is tied to ground. This would be a bolted fault which would trip the breaker in your panel. So this feature has to be bypassed unless you add a third relay and use a 4 wire nema 14 connector to accomplish this. But with a 3 wire nema 6 it's just not possible.

I'd love the see Phil comment on this (if he reads this), and how he addressed this issue in his evseupgrade mod.

[Volusiano]

Anyway, the temperature of the bottom of the EVSE sitting on a towel got to 129 deg F within two hours of charge start (240v, 12a) and had risen to 136 deg F at the end of the 6 hour charge cycle. That's measured on the outside of the package! I was thinking about upping the EVSE to 16a with Phil's additional upgrade but now I'm concerned about the temperature of the unit if I do so. At this point I need to test it at 120v, 12a to see what temp it gets to but I was surprised it got so high. This says the losses in the unit are greater than I expected. Hmmm...

Malcolm

When I tried my Rev2 mod, it ran pretty hot to me, too. I didn't have anything to measure the temperature with, but it was hot to the touch and you wouldn't want to touch it for more than a few seconds. However, when I asked Phil whether I should put a small fan on the box to keep it cool or not, he said no, that'd be wasteful to do. He said the upgraded EVSE will last longer than the lifetime of the car even with daily use.

Usually electrical components are rated at least at 60C (140F), so I guess while it may feel hot for us to touch, it may still be OK for the components.

[tps]

the charger doesn't like single phase 240 going through the CT. It thinks there is a current leak. I am still working out the issues.

Just my guess, it thinks there is leakage current because there is leakage current

One of the reasons they worry so much about the ground integrity and detecting leakage currents is that the car is a metal enclosure which is normally insulated from ground by it's tires until it receives a ground through the EVSE, so they are super paraniod about grounding and leakage in EVSE design.

[TomT]

Fair enough! As an EE myself, I can appreciate that!

I do. I just didn't feel like paying $240+ for this conversion when I can do it for $20. Plus being an electrical engineer, I just wanted to see how they did it and make the mod myself.

[TomT]

The general rule of thumb is that, if you can keep your hand on it for 5 seconds, it is not too hot.

Usually electrical components are rated at least at 60C (140F), so I guess while it may feel hot for us to touch, it may still be OK for the components.

[jclemens]

I'm with jwallace3 and I hope to learn more. I really want to know what it takes to change the duty cycle of the pilot signal quickly and easily. I really don't think it is a firmware hack.

As for the CT, 240V shouldn't affect it unless there really is a current leak. for 120, neutral and ground should never be connect anyways right?

I'm going to try it as soon as it get one.

jwallace3 please continue and you don't have to keep justifying to people with more money than brains.