OpenEVSE - Open Source Charging Station

[beehive]

Have not read all 340 posts to this thead yet, but most of them.
I built my own frankencharger. It uses a function generator, op amp, O scope, lab bench power supples and even auto jumper cables (I will never admit what they are used for).

I have discovered the car gets unhappy if it doesn't get 240 (or 120) pretty quickly after it has signaled it is ready for it. I figure it times out in about two seconds.

Right now, I simply engage a mechanical switch type connection right after the second beep. Takes two people, one to plug the J1772 connector into the car, the other to engage the juice. Next step is to automate that. I am thinking of using a triac/thyristor. Anyone know why that would not work? They do leak a tad. Much smaller, lighter and cheaper than a relay/contactor.

I took the stock leaf charger, opened it up, removed the PCB, jumpered the power lines straight through, added my circuit to the blue wire. I invested zero $$$ as I already had the op amp and resistors.

But seriously, if you wanted to do the wait for the beeps and throw the switch, you can be L2 pretty easy. I can make a circuit board to eliminate the function generator. Essentially what Chris at Open EVSE is doing. But I am planning on a module that simply replaces the module that comes with the charger. Then if you need to give it back, you just put the old module back in and hope they don't notice the holes in the plastic plugs that cover the screws. (You gotta drill them to get them out, but it doesn't ruin them).

Offlist I am [email protected]

So, relays or triacs (or SSR pucks)? Any opinions?

 

[Ingineer]

Have not read all 340 posts to this thead yet, but most of them.
I built my own frankencharger. It uses a function generator, op amp, O scope, lab bench power supples and even auto jumper cables (I will never admit what they are used for).

I have discovered the car gets unhappy if it doesn't get 240 (or 120) pretty quickly after it has signaled it is ready for it. I figure it times out in about two seconds.

Right now, I simply engage a mechanical switch type connection right after the second beep. Takes two people, one to plug the J1772 connector into the car, the other to engage the juice. Next step is to automate that. I am thinking of using a triac/thyristor. Anyone know why that would not work? They do leak a tad. Much smaller, lighter and cheaper than a relay/contactor.

I took the stock leaf charger, opened it up, removed the PCB, jumpered the power lines straight through, added my circuit to the blue wire. I invested zero $$$ as I already had the op amp and resistors.

But seriously, if you wanted to do the wait for the beeps and throw the switch, you can be L2 pretty easy. I can make a circuit board to eliminate the function generator. Essentially what Chris at Open EVSE is doing. But I am planning on a module that simply replaces the module that comes with the charger. Then if you need to give it back, you just put the old module back in and hope they don't notice the holes in the plastic plugs that cover the screws. (You gotta drill them to get them out, but it doesn't ruin them).

Offlist I am [email protected]

So, relays or triacs (or SSR pucks)? Any opinions?

This is dangerous because you are defeating the purpose of the EVSE; Safety. Not only that, but since there is no circuit interruption, your Leaf has likely set internal codes. If you have any trouble now, Nissan could easily void your warranty.

If you use SSR's/Triacs, you will likely have a ~1.5-2v per unit voltage drop, which at 16 amps means you'll need to get rid of around 50 watts of heat. (Plus that's all wasted electricity)

The most common failure mode for thyristors is a short on, so there is a critical safety issue here.

On top of that, I don't recommend posting your email address in public, as you'll likely get a lot of spam.

-Phil

 

[beehive]

Well, I own the largest ISP in the region, spam is a way of life. We have pretty good filters but they only get half of it.

Good point about failing ON. I have had that happen before. I did a small subdivision water syster 100% solar and we had a puck type SSR fail on and flood the pump house. But that was only after a contractor hit the pump cable with a backhoe.

Just hate the extra current required by a relay coil. But don't want to deal with the heat of the Triac either. So, I guess relays it is.

 

[mitch672]

How about you build a normal EVSE, you know with a J-1772 cable, relay, OpenEVSE board, 12V power supply, it doesn't take much. Phil is too nice to say this, but modifying the onboard charger, to defeat the saftey interlock / J-1772 handshake has to be THE dumbest idea I have ever heard, and I've heard some real winners

 

[chris1howell]

Just hate the extra current required by a relay coil. But don't want to deal with the heat of the Triac either. So, I guess relays it is.

The relay most OpenEVSE builders use draws 141ma @ 12V or 1.6 watts, so about 30x less loss than a SSR ~50w 240v 16a.

I would also echo the previous statements, if you want to DIY start with OpenEVSE either a prebuilt board or print your own board with the .brd files on the OpenEVSE site. If you print your own board and have the J1772 cables and a 12v power supply you can build the whole thing including relay and GFCI coil for less than $50...

Frankencharger bypasses all the safety features and sounds pretty dangerous.

 

[davewill]

If you print your own board and have the J1772 cables and a 12v power supply you can build the whole thing including relay and GFCI coil for less than $50...

Frankencharger bypasses all the safety features and sounds pretty dangerous.

It would be cool if he made an OpenEVSE board that was specifically designed to upgrade the stock L1 to L2/OpenEVSE. It would be an cheap starting point for lots of people who want to build their own, but don't want to invest in a new J1772 cable and plug, or deal with creating a housing. It could be made to fit into the L1's case and use the same status LEDS.

 

[chris1howell]

It would be cool if he made an OpenEVSE board that was specifically designed to upgrade the stock L1 to L2/OpenEVSE. It would be an cheap starting point for lots of people who want to build their own, but don't want to invest in a new J1772 cable and plug, or deal with creating a housing. It could be made to fit into the L1's case and use the same status LEDS.

davewill - that was my original intent of the project that turned into OpenEVSE, but along the road I decided I wanted a second fixed EVSE and because I leased my leaf I did not want to crack my Nissan EVSE open.

I have an all in one board with all the OpenEVSE + Advanced Power supply features pretty much ready to go... If someone has a Nissan unit that is open or can be opened up (or even a broken unit) and they can live without it for 4-6 weeks, I would be happy to finish up the design... I would be willing to give the volunteer a copy of resulting EVSE board for no cost... I agree, it would be nice to have a drop in replacement.

 

[davewill]

... I would be willing to give the volunteer a copy of resulting EVSE board for no cost... I agree, it would be nice to have a drop in replacement.

Sadly,* I have already upgraded my EVSE. But, yes, it would make a nice safe DIY upgrade for the tinkerers among us.


* OK, not sad at all. :lol: Actually I am so glad to have my EVSEUpgrade. It has saved my bacon during the last six weeks of construction at my house where access to my garage and Blink has been blocked most days.

 

[RickS]

Heck I'm glad I have my open EVSE! A few weeks ago when Blink pushed their last update mine scrambled the SD card and wouldn't boot up and wouldn't charge. Granted Ecotality send someone out early the next day to replace it, but I blatantly made it very obvious when they came that I had the car plugged in to the outlet they installed with not their box. I figured their tech would have at least said something as the plug I used on my open EVSE was a REMA plug that looked just like theirs, but he didn't say anything. :roll:

 

[RSH]

I can't recommend Chris' Open EVSE enough. He was kind enough to take my broken ChargeAmerica unit and convert to his system. It has worked flawlessly ever since. I also have Phil's upgrade of my Nissan unit, which I now carry in the car. For awhile it was my only means to power-up after the ChargeAmerica failed. Having both a permanent and portable means of charging at 240 volts is most convenient and provides me confidence that I can always get power. Thanks Chris and Phil.

 

[GlennD]

I use my portable Open EVSE every day at work. I figured that working for a city there is no way I would get permission.

I emailed a request that bounced around until the office of sustainable energy gave me permission.

I only use it to top off after my 20 mile trip from Anaheim to North Long Beach but the fact that I can use my portable EVSE to top off is comforting.

 

[eHelmholtz]

I have an all in one board with all the OpenEVSE + Advanced Power supply features pretty much ready to go... If someone has a Nissan unit that is open or can be opened up (or even a broken unit) and they can live without it for 4-6 weeks, I would be happy to finish up the design... I would be willing to give the volunteer a copy of resulting EVSE board for no cost... I agree, it would be nice to have a drop in replacement.

I wonder if the Volt L1 unit can be gutted for the same purpose - I have one to volunteer

 

[fotajoye]

+ONE

 

[mitch672]

Isn't the issue with the Voltec unit that it's built with 16AWG wiring? In that case it could be converted to level 2, but the current would need to be limited to something like 12A for safety, as 16AWG is really not rated for even that (14AWG is 15A, while 12AWG is rated at 20A)

Doesn't seem worth the effort, sorry to say.

 

[chris1howell]

I believe the other part of the problem with the Voltec is the plastic enclosure is fused closed which makes it extremely difficult to take apart and put back together again...

 

[Barbouri]

Just received a new batch of prototype Open EVSE V3 boards today.
This revision adds L1/L2 sense to the main board, along with decoupling caps on all IC's.
I am also testing out a new 5 volt regulator to increase efficiency.

Greg C.

 

[chris1howell]

Very nice... please let is all know how it works. I an quite interested in your regulator, is it switch mode? I may have to incorporate several of.your changes into the SMT board.

 

[mitch672]

Looks like he is using a Maxim 5033 from the silk screen on his PCB, it's availble though hole and surface mount

http://datasheets.maxim-ic.com/en/ds/MAX5033.pdf" onclick="window.open(this.href);return false;

 

[Barbouri]

Very nice... please let is all know how it works. I an quite interested in your regulator, is it switch mode? I may have to incorporate several of.your changes into the SMT board.

Chris,
I am using a MAX5033 Step-down DC-DC converter.
It is pulse-width modulated (PWM) converter and operates at a fixed 125kHz switching frequency at heavy loads, and automatically switches to pulse-skipping mode to provide low quiescent current and high efficiency at light loads.
I tested the circuit on one of the boards this evening with great results.
Once I get this board populated with components minus the MID400 HV sensors, I will compare the power usage against a V2 board.

Load setup for testing and partially populated V3 board

At 300 ma load: 5.06 Vdc and 6.2 mv AC ripple.

Greg C.

 

[chris1howell]

Cool. I just sent out the new board design today. I have not paid yet so I can pull it back to change it a bit. I am really interested in this beacuse it goes with the other changes I made. I put both the lcd port and pilot dcdc/opanp on a transistor/digital line so they can sleep or be reset. With the better 5v regulator the standby load could be way lower than the already low 1w...

Greg would you mind e-mailing your schematic?