Inside the NA spec L1 EVSE

So, since I probably will never use it, I decided it would be OK to void the warranty on my Nissan L1 EVSE to help you guys figure out what made it tick. First though, I decided to plug it in, to at least make sure it actually worked before I tore it apart:



However, I was admonished that I should not resolve or remodel the EVSE. :lol: :



The feet were tougher than I expected, and I had to drill through them to get at the six screws beneath, which were the torx type common on most electronics these days:





Inside I beheld the beauty of the electronics. The box was sealed with a silicone membrane (the gray stuff) much like you find in use for many automotive gaskets these days. And the circuit board was inside a plastic tray that was filled with black goop, possibly also silicone based:



I noticed immediately that a lot of the components were labeled for 250v or better. These included the fuse which was 250v 15a. However, there was definitely a transformer in there, but it wasn't to step up from 120v to 250v as I sort of expected. Instead it was for stepping down from 120v to AC20.9v.

I don't understand a lot of what the circuity within is probably going to be for, so I'll let you guys examine the pictures and decide for yourselves. The one thing that does kind of jump out at me is the silver wire running along side of those boxes labeled Omron - that definitely looks like a jumper that one might cut under differing circumstances.





This is the wiring to the J1772:



















Anything else you want to know, just post and I'll try to supply the info.

If I'm not mistaken, I think I just heard Gary giggle like a child and pour himself a glass of wine.
:mrgreen:

Looks like they went all out with the weather proofing. Interesting about the 250v thing, it's probably designed to be a 110/220 international product. If only the plug is different, I wonder if you could find or build an adapter to an electric dryer plug and charge at a faster rate. You up for trying that?

MrZorg said:

Looks like they went all out with the weather proofing. Interesting about the 250v thing, it's probably designed to be a 110/220 international product. If only the plug is different, I wonder if you could find or build an adapter to an electric dryer plug and charge at a faster rate. You up for trying that?

Click to expand...

I'd want someone who was electronically inclined to look at it first. I'm sure it's more than the plug, otherwise that 120v step-down transformer wouldn't be there.

Hmm, I guess those pictures I PM'd you a few minutes ago arrived a little late. I did some exploring also. I don't like that transformer that clearly says 120 V in, 20.9 V out; if we feed it 230 V, it will put out almost 42 V, which could be hard on electronics. Assuming that the smoke doesn't leak out of the transformer itself.

-Karl

Excellent photos!
It looks like they really sealed the box well, and the conformal-coating / potting should also help with weather, rough handling, and so on.

I'm now less convinced that this would be an easy conversion to 220v.

First, I wouldn't read anything into the fuse being 250v. That's pretty universal.

It's the transformer 120v to 20.9v that would need to be replaced.. does it look like the transformer is involved in the potting compound, or is it sitting "on top" and held just by those screws?

The jumper you point out does stand out as a cut option of some sort. No idea what it would do, but it looks easily reversible for someone who wanted to try cutting it.

True. It does make me wonder about importing a European model though... Wonder how much this unit costs as a dealer part...

GroundLoop said:

Excellent photos!
It looks like they really sealed the box well, and the conformal-coating / potting should also help with weather, rough handling, and so on.

I'm now less convinced that this would be an easy conversion to 220v.

First, I wouldn't read anything into the fuse being 250v. That's pretty universal.

It's the transformer 120v to 20.9v that would need to be replaced.. does it look like the transformer is involved in the potting compound, or is it sitting "on top" and held just by those screws?

The jumper you point out does stand out as a cut option of some sort. No idea what it would do, but it looks easily reversible for someone who wanted to try cutting it.

Click to expand...

The transformer is just held in with screws. It comes off the circuit board via the two thicker white wires at the connector closest to the fuse and back into the circuit board via the two thin yellow wires at the connector closest to the capacitor.

Oh, nice! So, find a suitable replacement and it should work. Of course, then it WON'T work on 110 anymore. Perhaps an enterprising hacker could rig a switch.

Or, if they're not too expensive, just buy a second and carry them both. How interesting.

Sent you a PM

The jumper is probably there because the pcb is single-layer, rather than an option wire to cut.
To do anything to (with) this, you'd have to de-pot the pcb and scratch out a schematic.

Good pictures, thanks "K" for the PM'd ones also.

Not "trivial" to do anything with.
A 240v 12-amp unit is likely possible by replacing the 120/20.9 transformer,
but I cannot tell if other components would need changing.

Maybe the SPX all-voltage, adjustable-current (32-amp max), plug-in EVSE will be available "soon"?

DeaneG said:

The jumper is probably there because the pcb is single-layer, rather than an option wire to cut.

Click to expand...

I don't know.. it seems to set up awful high, like it's intentionally outside the potting.
If it was just a PCB routing wire, I'd expect it to hug the board and hide under the compound.

Possibly carries 12A of the "Neutral" (white wire) of the 120V AC input to the 2nd "Relay" (?) module?

GroundLoop said:

I don't know.. it seems to set up awful high, like it's intentionally outside the potting.
If it was just a PCB routing wire, I'd expect it to hug the board and hide under the compound.

Click to expand...

I agree - realized the same thing a while after posting, oops!

mwalsh said:

I'd want someone who was electronically inclined to look at it first. I'm sure it's more than the plug, otherwise that 120v step-down transformer wouldn't be there.

Click to expand...

that step down would seem to drive the pilot signal. Driving that transformer with 240 would double the output and may not fair well with the pilot signal circuit. But I am not electronics expert.

Yeah, it's just a basic transformer... We throw 240 volts into it and we'll get 41.8 volts out... Not what I was hoping for. Well, the good news is that they obviously designed the unit to easily install whatever kind of transformer they want!

Now the trick will be to find a 20.1 AC power supply that can accept 100-240 volts input. If I had to guess, the unit probably has a tolerance between 17-18 volts to about 24-25 volts, since any fluctuation in the primary line voltage will directly affect the AC output on the transformer...

On another note, awesome weatherproofing! I was definitely wondering how well it would handle the elements, but it's sealed up really well!

Got it figured out! We need to add a 120 volt lamp in series with the power supply when it's connected to a 240 volt source!

http://www.mouser.com/Optoelectronics/Lamps-Holders/Panel-Mount-Indicator-Lamps/_/N-770xs?P=1yzudos

If you want it to be dual-voltage, add a simple single-throw, double-pole switch that takes the lamp out of series when you want it to run from a 120 volt source!

DarkStar said:

Got it figured out! We need to add a 120 volt lamp in series with the power supply when it's connected to a 240 volt source!

http://www.mouser.com/Optoelectronics/Lamps-Holders/Panel-Mount-Indicator-Lamps/_/N-770xs?P=1yzudos

If you want it to be dual-voltage, add a simple single-throw, double-pole switch that takes the lamp out of series when you want it to run from a 120 volt source!

Click to expand...

Ummm, no. Voltage drop across a resistive load is dependent on the current being pulled through the load. This is just a bad idea all around.


The wire in the air is most likely a shunt. (Like this http://www.token.com.tw/current-sensing/open-air.htm) The board measures the voltage across the shunt and it can then calculate the current through it. It could also be just a jumper as others have mentioned, but I would agree there would be no reason to keep it off the board like that.

I think you nailed it, Turbo - looks like a shunt to me as well.

The potted electronics do the magic. It would be nice if everything inside the package was powered from the transformer, and it would make good sense to do that, but I think we'd have to remove the potting to know for sure. And I've destroyed too many assemblies trying to dig/pry/heat/peel/remove potting to want to do it again.

It is encouraging that the relays are 12V and the large capacitor is rated at 310V, though. It really might be as easy as a transformer swap. (fingers crossed)

Thanks for the teardown, Mike!

Andy