OpenEVSE - Open Source Charging Station

[GlennD]

This is a photo of the load resistors. I used a 2W 220 ohm on the 12V and a 180 ohm 1/2W on the 5V. The 12V load could be 1W but a 1W ran hot. With the power supply efficiency the load draws just under 1W. It completely stabilizes the 5V and gets rid of the spike.

 

[GlennD]

Well, The 12V should be a 1W resistor but the first one ran hot. I just purchased some more and the 12V does not run hot. It should not since the power is just over 1/2W. The old resistor must have been an exception. A 1W mounts much nicer.

 

[GlennD]

I was moving Tony's unit into a box for long tern storage since He seems to be in no hurry to pick it up. While I had it in my hands I looked at the date code on his module. It was 1244.

 

[pchilds]

I was moving Tony's unit into a box for long tern storage since He seems to be in no hurry to pick it up. While I had it in my hands I looked at the date code on his module. It was 1244.

Darn, I could have taken it to him, if you still have it next time, let me know.

 

[GlennD]

I was moving Tony's unit into a box for long tern storage since He seems to be in no hurry to pick it up. While I had it in my hands I looked at the date code on his module. It was 1244.

Darn, I could have taken it to him, if you still have it next time, let me know.

I used some parts he was going to replace so he needs to pick it up. I would rather the parts replaced than the money for them.

 

[TonyWilliams]

I was moving Tony's unit into a box for long tern storage since He seems to be in no hurry to pick it up. While I had it in my hands I looked at the date code on his module. It was 1244.

Darn, I could have taken it to him, if you still have it next time, let me know.

I used some parts he was going to replace so he needs to pick it up. I would rather the parts replaced than the money for them.

Sorry, Glenn, but I've been in the Middle East most of 2014, and am currently in Europe through 11 July.

Let me know exactly which parts to replace and I'll have them shipped. I will also send you a shipping label to send the completed unit to my house.

Tony

 

[GlennD]

My comment was to imply I was moving the unit to the garage for long term storage. As far as I am concerned it can stay on the shelf forever. I was just getting it out of the way.

A while back I sent you an Ebay link for the 50A Spa contactor. I guess you could pay me for it and I will order it. It was a spare that is here to scare the one I used into its best behavior.

 

[asimba2]

What are the two readouts on the bottom line of the openevse screen?

 

[MikeinDenver]

What are the two readouts on the bottom line of the openevse screen?

Left is the amount of time spent charging the right I believe is the time.

 

[asimba2]

Left is the amount of time spent charging the right I believe is the time.

I was hoping the right side was kilowatts consumed. Since my openevse is still in the mail, I haven't had a hands-on with it.

Thanks for the reply.

 

[GlennD]

Left is the amount of time spent charging the right I believe is the time.

I was hoping the right side was kilowatts consumed. Since my openevse is still in the mail, I haven't had a hands-on with it.

Thanks for the reply.

You only get the time of day if you have the real time clock. Given the small added cost it is worth it just for the time even if you do not use the timer.

If you enable the RTC with no hardware it displays garbage.

 

[asimba2]

I did get the rtc and Chris' nice enclosure. After six months of making due with L1 charging, I can't wait to get it. I got my nema 14-50 outlet installed and ready for use. My service panel is on the outside wall of my garage, so the wire pull was only a few feet. . Went with overkill 6/3 wire to support 50 amps in the future, but right now it's on a 30 amp breaker.

 

[GlennD]

I did get the rtc and Chris' nice enclosure. After six months of making due with L1 charging, I can't wait to get it. I got my nema 14-50 outlet installed and ready for use. My service panel is on the outside wall of my garage, so the wire pull was only a few feet. . Went with overkill 6/3 wire to support 50 amps in the future, but right now it's on a 30 amp breaker.

Your panel situation is like mine. Simple install. My only problem is that I only have a 100A service panel so 40A is it.

With Chris's housing kit you should set the EVSE current to 24A if you are using his fuses. 80% of 30A is 24A. His relays are good to 30A. Yellow push on terminals are 25A.

In my EVSE I have a 50A 240V contactor and a Liviton #10 J1772 cable. I have a 14-50 socket wired with #8 wire on a 40A breaker. I set my EVSE to 32A (80% of 40A). My nissan Leaf can only take 27.5A but when RAV4 EV owners come by they can take it all.

 

[nsayer]

I don't normally like to pre-announce stuff, but since the prototype worked perfectly... what the heck.

I've been working on my own version that I call OpenEVSE II. It too is designed to fit in Chris' very, very nice enclosure, but it differs from Chris' board set somewhat.

1. The high voltage and logic/display systems are on separate boards. This makes it safer to troubleshoot, if needed.
2. In addition to the GFI coil, there is a connector for an ammeter CT coil. This will show the current being drawn by the vehicle while it's charging.
3. It wasn't tested in the prototype, but the plan is for the next version to have a voltmeter. This will allow the display to read power (kW) rather than current (amps).
4. There is a continuous ground test, rather than just one on startup.
5. There is no longer a relay test function. No AC test wiring (to the load side of the relay) is required.
6. The display and RTC are not optional.
7. There is a choice of two different HV boards - one has a pair of relays and will operate at both L1 and L2. The other is intended to be used with a contactor, for higher powered, 208/240v only designs. A future contactor board for Europe will add support for the Menekes PP line and actuator lock.

The prototype unit was a success, and the next version (which will likely be the release version assuming it doesn't go spectacularly wrong) should be ready at the end of the month.

 

[asimba2]

I ordered Chris' charge station combo and got it completed the day I received it. It's up and running and appears to function exactly as it should. Like everything I build myself, I'm always a little nervous until the device proves itself, so can you critique my build and see if anything stands out as suboptimal?

I used all the parts from the kit, however the 32A "heavy duty" Dostar J1772 I bought from the store had wiring too thick to slip inside the supplied wiring connectors. On the connections from the J1772 cord to the relays, I removed the plastic wiring connector housings, opened up the slotted part where the wire would normally crimp, then I soldered and shrink-wrapped those connections. Any problems there?

Also, all the pics I've seen on the web have the charge current set to 24 amps. Mine jumps from 20 amps to 25 amps...was there a software or hardware change that was recently made? I have it set to 25 amps, is that safe given the above build? I am using a 40 amp range cord and a 32A Dostar J1772. The outlet is a NEMA 14-50 with 6/3 wire on a 30 amp breaker. Car is a 2013 with the 6.6kw charger.

Thanks.

 

[GlennD]

I ordered Chris' charge station combo and got it completed the day I received it. It's up and running and appears to function exactly as it should. Like everything I build myself, I'm always a little nervous until the device proves itself, so can you critique my build and see if anything stands out as suboptimal?

I used all the parts from the kit, however the 32A "heavy duty" Dostar J1772 I bought from the store had wiring too thick to slip inside the supplied wiring connectors. On the connections from the J1772 cord to the relays, I removed the plastic wiring connector housings, opened up the slotted part where the wire would normally crimp, then I soldered and shrink-wrapped those connections. Any problems there?

Also, all the pics I've seen on the web have the charge current set to 24 amps. Mine jumps from 20 amps to 25 amps...was there a software or hardware change that was recently made? I have it set to 25 amps, is that safe given the above build? I am using a 40 amp range cord and a 32A Dostar J1772. The outlet is a NEMA 14-50 with 6/3 wire on a 30 amp breaker. Car is a 2013 with the 6.6kw charger.

Thanks.

The Dostar cables fit a PG25 gland. It is slightly larger so the mounting hole would need to be filed out.

Chris ships the units with firmware in 5A steps from 10A to 80A to match the J1772 spec with a reasonable table. I edit the table from 10A to 50A in 2A steps. If you are near Anaheim I would be happy to reprogram your unit.

You can also set up a system with the OpenEVSE files and Arduino 1.01. Later versions have changes and they do not work. Lincomatic favors the early version 0.0023 as it makes smaller files. That is why the files from his github site end in PDE instead of INO.

The table is in plain text and you can make it with your own custom steps with an ISP programmer.

Personally I think 25A is fine. 24A is the derating spec for 30A. You may find the fuses run pretty hot but they are designed to fuse (melt) at sustained 30A use.

I can send you a CD with 1.01 and the proper libraries if you plan to reprogram your unit. PM me with your address.

 

[asimba2]

Chris ships the units with firmware in 5A steps from 10A to 80A to match the J1772 spec with a reasonable table. I edit the table from 10A to 50A in 2A steps. If you are near Anaheim I would be happy to reprogram your unit.

The table is in plain text and you can make it with your own custom steps with an ISP programmer.

Personally I think 25A is fine. 24A is the derating spec for 30A. You may find the fuses run pretty hot but they are designed to fuse (melt) at sustained 30A use.

Glenn, thanks for looking over my build and offering the reprogram. I'm fine with the 5A steps, I mainly wanted to know if it was safe to use at 25 amps. If I set the max current on the EVSE to 20 amps, is the EVSE simply telling the car via the pilot signal that it can only provide 20 amps and therefore that becomes the rate of charge? And should I set it at 20 amps to keep the heat down?

Also I noticed there's a Level 1 setting. Does the EVSE then use only one leg of the 240V and essentially charges the car as if I was using the supplied Nissan/Panasonic EVSE? I'm basically looking for clarification on how the settings in the EVSE interact with the car.

Thanks!!

 

[GlennD]

L1, L2 are definitions. Most EVSE's have a fixed pilot and assuming it was set to 10A then at 120V it would be 1200W and at 240 it would be 2400W.

The OpenEVSE has a pair of optical isolators designed for AC use. It uses them to check for a ground on the Lines. If it is plugged into 120V then only one line will see voltage. It then knows that it is connected to 120VAC. It then uses the 120V table (default is 12A). If it sees voltage on both lines it knows it is connected to 240VAC and it uses the L2 240V table. If it sees no voltage on either line it assumes the ground is bad and it errors out.

You can not tell a 240VAC connected unit that it is a L1 unit. It does not work that way. OpenEVSE has settable current via the pilot. You could alter the current and have the same effect as an L1 connected unit.

Normally it is set to auto and it sets itself. In the first menu setting you can force it to use the L1 or L2 table. This only alters the pilot. Physical connections determine the connection. If it is connected to 240V and you use the L1 table then bamm, it is now a 12A unit but still at 240V.

 

[asimba2]

Thank you for that explanation. I'll use it set at 20 amps for now and assuming I'm feeling comfortable with the amount of heat being generated, I'll bump it up to 25 amps.

 

[GlennD]

Assuming you have the time at discounted rates 20A is fine. The original Ingineer mod only doubled the voltage leaving the current the same. 2800W was enough for most over night charging.

Ingineer is a fine engineer and the stock Nissan cable was rated for 20A. I am sure leaving 8A on the table pissed him off. His current mod can be set to 20A.

Realistically for home use it really depends on your available time. 20A at 240V is likely more than enough. It is near Nissan's 27.5 A max.

In my case Anaheim has no tiers so I can charge when I like. Other areas charge to the max during prime time so it makes sense to charge late at night.