QueenBee
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Re: Converting the stock EVSE to an OpenEVSE unit

Wed May 15, 2013 8:04 pm

henrysunset wrote:How does this OpenEVSE modification compare to the more common modification Phil offers to convert the stock unit to 240v?

Specifically:
- What additional features will I get with the OpenEVSE (based on current firmware - I understand that firmware updates can result in new capabilities)
- How does this modification compare in terms of cost and complexity to implement?
- Anyone try to support the recent Wifi capabilities of the evolving EVSE firmware with this modification?
I would not consider this a real alternative to Phil's EVSEUpgrade. The complexity to implement vs Phil's service is off the charts.

Cost wise it's probably reasonably similar if you have to buy everything to complete this vs just sending it to Phil.

AFAIC the reasons one would want to perform this mod vs just building an OpenEVSE from scratch or getting an EVSE Upgrade is they want to prove it can be done, they like building things and they've already built enough standard OpenEVSE and wanted a new challenge, etc. :)

If you wanted to build an OpenEVSE instead of using the EVSEUpgrade service I think I would recommend building one from scratch and then selling the Panasonic EVSE. It'll probably end up costing you nothing after all is said and done.

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Ingineer
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Re: Converting the stock EVSE to an OpenEVSE unit

Wed May 15, 2013 10:20 pm

Reliability is probably also something you're going to lose in a DIY effort. I bet that one good drop onto pavement will likely render any DIY conversion of this type damaged. This is of the reasons Panasonic goes to great lengths to use a special energy-absorbing potting compound.

Also, it would be almost impossible to do this conversion in a 2nd generation (2013) EVSE due to the lack of room and the fact that the PCB is permanently potted into the bottom housing.

-Phil
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TonyWilliams
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Re: Converting the stock EVSE to an OpenEVSE unit

Thu May 16, 2013 12:20 am

Ingineer wrote:Reliability is probably also something you're going to lose in a DIY effort. I bet that one good drop onto pavement will likely render any DIY conversion of this type damaged. This is of the reasons Panasonic goes to great lengths to use a special energy-absorbing potting compound.

Also, it would be almost impossible to do this conversion in a 2nd generation (2013) EVSE due to the lack of room and the fact that the PCB is permanently potted into the bottom housing.

-Phil
Apparently, some of the Tesla portable EVSE (Model S "UMC") are burning up. I wonder if its a lack of energy absorption from being dropped?

The interchangable plug adapters are also melting their connection pins (they are tiny). I'm modifying a few with J1772 plugs for Rav4 drivers, but I'm bumping into a new problem. Tesla decided to use two conductors in parallel per power pin, which causes a dilemma as to how to terminate them.

I wanted to just use a 4 indent die to crimp on the pins, but now I'm thinking that the two conductors should be combined to a single 6 - 8 gauge conductor to be crimped on the J1772 power pin. Of course, I still don't know how I would want to combine those two 12-ish gauge conductors into one 6 - 8 gauge.

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Ingineer
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Re: Converting the stock EVSE to an OpenEVSE unit

Thu May 16, 2013 10:01 am

I just did one of these conversions for Waidy:

Image

The cool thing is Tesla's inclusion of a handy 3.3v source which is normally used for the charge door release transmitter. This enabled easy addition of a bright LED for nighttime, something not even Tesla thought of!
Image

I opened one of the UMC's up, but it's a pretty destructive process due to the housing overmold and it being glued shut. If not for this "one way trip", I'd have simply replaced the thin (too thin?) Tesla cable.

Tesla is really pushing the limits! They use two 2.5mm wires for each side, (Equivalent to #13AWG) and inside the box they use the exact same relay ClipperCreek uses on the LCS25, a single 30A rated relay. (at 40A!) It's arguable that splitting the high-current between 2 smaller conductors is better for heat-dissipation, but then you have the pesky termination issues. Inside the UMC, Tesla welds the 2 conductors to a little square terminal, then screws this to a PCB terminal. So this is a good termination and it looked well-done by my assessment. Having 4 smaller wires instead of 2 larger ones definitely makes for a smaller, more flexible cable overall, so regardless of any potential current handling gain, it's good ergonomically.

I definitely don't like their interchangeable right-angle plug connector design. First off, if you are going to do right-angle, why not make it symmetrical? That way you could flip it 180 degrees if your outlet is installed upside-down. (Patent-Pending! =)

Their "dongle" design makes for compact and simple plug adapters, but it ends up being a really big blob, especially when used on smaller outlets (NEMA 5-15). I think I prefer having a short length of cable for each adapter, as this makes the final plug smaller, more compact, more flexible, and spreads out heat.

Ok, onto my conversion. Sorry, I didn't think to take pictures of the pin connection detail until it was already all assembled. Here's the best I can do:
Image

Since the "no-name" Chinese handle pins are made for much larger wire, you cannot crimp it by itself and get a reliable 40A connection. I took a crimp ferrule from a yellow butt-splice connector, and crimped the 2 Tesla wires into that, which were very well crimped, then crimped and soldered that into the no-name pin. I believe this is as good as I can make it.

I would not trust solder alone, there must be a solid mechanical bond first at these current levels with the relatively tiny wires. If you are soldering anything, it absolutely must not be allowed to move, as you will have stress-concentrations where the solder wicking inside the wire strands ends.

Needless to say, I'm not doing another one of these. It's a lot of work to do properly, I'm not sure I like the "no-name" Chinese handle, and the UMC itself isn't the hardiest design to begin with, though it is sexy!

-Phil
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Ingineer
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Re: Converting the stock EVSE to an OpenEVSE unit

Thu May 16, 2013 11:30 am

For those curious, here's some shots of the UMC. Note the 30A relay that is run at 40A:

Image

Image

-Phil
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

GlennD
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Re: Converting the stock EVSE to an OpenEVSE unit

Sat May 18, 2013 10:35 am

I think comments about the OpenEVSE being fragile are off the mark. Certainly the potted stock unit is more rugged but I am sure that if I dropped my unit while pulling it out of the case it would survive. Neither unit would survive being run over.

I built this unit for a number of reasons:

I built it as a proof of concept. I wanted to see if the EVSE Plus would allow a full function EVSE to fit in the stock Panasonic housing.

I wanted a 240VAC unit for a backup for my home and work chargers. I have used my L1 unit maybe 3 or 4 times in the early days when I suffered from range anxiety. I can still use the unit as a L1 EVSE. I can never see me using it in a RV park. I have not ever built an adapter.

I constructed as apposed to buying Ingineer's unit solely because there is no information available on what the conversion consists of. I have built OpenEVSE's from the eatly days to current. I have a lot of experence with them. I try to have service manuals or information for most of my equipment.

There is no doubt Ingineer's conversion is safe and reliable but it is not for ME.
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QueenBee
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Re: Converting the stock EVSE to an OpenEVSE unit

Sat May 18, 2013 12:08 pm

GlennD wrote:. Neither unit would survive being run over.
I actually thought that was one of the features of the Panasonic?

GlennD
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Re: Converting the stock EVSE to an OpenEVSE unit

Sat May 18, 2013 2:03 pm

You got me, I simply do not know. The case is rugged but I do not think it is that rugged. It surly is made better than you could do yourself.
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Back to a Cirrus White 2017 B250e
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Ingineer
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Re: Converting the stock EVSE to an OpenEVSE unit

Sat May 18, 2013 5:42 pm

I can assure you that the Panasonic unit easily survives drive-over. I've got a picture of my LEAF somewhere parked on one.

Out of thousands of units, The only time we've seen physically broken ones is when crazy things happen such as a dog literally chewing through the cable! (There were also teeth marks on the unit, but it hardly did anything!)

Image

They just simply do not fail. I've seen a number of other makes with all-manner of problems related to physical design.

No offense Glenn, but I see numerous potential failure modes of your conversion if subjected to high-G loads. For instance; If it lands the right (wrong) way, the fuses will pop right out of their holders, but that's an easy fix. If it drops upside down, there's a very good chance the MPD power module will simply "unsolder" itself, or if it's a side impact, it'll shear off it's legs. Good designs using large devices mounted only by solder on PCB's supply adjunct physical mounting, as reliability is poor when using solder as a sole mounting strategy.

I can't tell you how many times I've seen large electrolytic caps fall off boards that are subjected to rough (or automotive) environments. Take a look at the Nissan (Nichicon) on-board charger. All large components are mounted off-board or have some form of auxiliary mounting system.

-Phil
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Re: Converting the stock EVSE to an OpenEVSE unit

Sun May 19, 2013 7:57 am

Ingineer you bring up a good point about the power module. I was able to use some JB Weld to securely afix the power module to the PCB. As for the low mass fuses jumping out of the powerful clips of a 30A fuse holder, well that one I will believe when I see it.
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2013 Pearl White SL Premium
Traded for a Cirrus White 2014 Mercedes B (totaled)
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Loved the VW but it sat too low for my old body
Back to a Cirrus White 2017 B250e
White Ioniq limited.It sits just fine

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