OpenEVSE - Open Source Charging Station

[GlennD]

In my case I used a different contactor with 2 coils. It draws 10A at 12V until it pulls down and then only draws .1A to keep it pulled in.

Interesting! Can you give us a supplier/mfg/part number for that contactor.

Dan

It was from Ebay. I purchased 2 since you can not count on Ebay. It has a microswitch on the side that opens the high current coil when it is fully pulled in. It is a normal 3 pole 50A contactor other than that.

I am using a 5A switching supply with a 4700 mfd cap on the output. It only has to supply 10A for a few miliseconds.

When I get home I will be happy to supply a part number.

 

[evnow]

For those who built a 70A EVSE, here is a question.

How did you pull the wire from the panel ? Does it have to be in the wall - can it be in a conduit outside the wall ?

Also, if you got an electrician to do the work, how much time did it take (if the panel was in the garage). I talked to a wacko electrician who gave me a large estimate.

 

[mitch672]

For those who built a 70A EVSE, here is a question.

How did you pull the wire from the panel ? Does it have to be in the wall - can it be in a conduit outside the wall ?

Also, if you got an electrician to do the work, how much time did it take (if the panel was in the garage). I talked to a wacko electrician who gave me a large estimate.

Did it myself, my 125A garage subpanel is surface mounted, so I ran 1" SCH40 PVC up and over a doorway, my 75A OpenEVSE is mounted next to that door. I used #3 AWG THHN for the 2 hots, and a #6 AWG ground... I checked the wire fill calculator before choosing the conduit size.
FYI "Stayonline" has great prices for #3 THHN (.75 per foot)

 

[Don123]

Also, if you got an electrician to do the work, how much time did it take (if the panel was in the garage). I talked to a wacko electrician who gave me a large estimate.

Your estimate was just for his time? . . . . or was it for time plus materials?

Depending on the length of the run, materials alone for a 75 amp installation could be a 'large' number

Don

 

[evnow]

Also, if you got an electrician to do the work, how much time did it take (if the panel was in the garage). I talked to a wacko electrician who gave me a large estimate.

Your estimate was just for his time? . . . . or was it for time plus materials?

Depending on the length of the run, materials alone for a 75 amp installation could be a 'large' number

Don

Just labor.

 

[GlennD]

 

[borland]

That doesn't look like a 2-coil relay, but you said it has a small 12V actuator on the side to switch on the coil. Since it is a 3-pole unit, you'd expect it's coil to draw more current and produce more heat.

Here's a smaller 2-pole 40 amp contactor with single 12V coil that that some here have used which would be good for a 32 amp OpenEVSE.... a Magnecraft W199X-7...

and the data sheet..

http://www.serelays.com/library/section6/105A_199.pdf

As you can see from the datasheet, they make a 50 amp version but those seem to be hard to source. Here's a link to see some prices..

http://octopart.com/w199x-7-magnecraft-25415

 

[borland]

Diversified Stage has just launched it's web store. So people can now purchase their enclosure kits..

https://ssl.diversifiedstage.com/es...roducts_id=3&zenid=eoqpgqdgbkh5jpvi44dh62qe20

 

[DanBaldwin]

Thanks for the info GlennD.

Dan

 

[GlennD]

Quote:

That doesn't look like a 2-coil relay, but you said it has a small 12V actuator on the side to switch on the coil. Since it is a 3-pole unit, you'd expect it's coil to draw more current and produce more heat.

The contactor has both coils in parallel until it bottoms out. At that time the nylon actuator causes the microswitch to close opening the high current coil leaving the low current holding coil.

The contactor I was originally going to use was a 2 pole 50A contacts, 240V coil. That is the one I tested and did not use.

The Ebay unit cost $20 and the other now unused one was around $40 as I recall.

In any event My EVSE is finished and I have no plans to modify it.

 

[waidy]

New questions:
(1) Would the OpenEVSE Plus (v2) allows charging in either 120V and 240V (auto sensing?)
(2) Would the ready-made box from Diversified Stage big enough to host a 75Amp camper (out of curiosity) ?

Your list looks pretty good you will also need a relay/contactor and the CT for GFCI but I think you covered most of the big parts... I would not worry about the 8awg wires, when I build an EVSE I usualy take a little wire from the AC cord and a little from the J1772 to make all the high voltage connections. The wire in the cords are usualy higher quality and much more flexable than standard cable.

(1) Yes, the OpenEVSE Plus (v2) does auto sense Service Level when using a relay with a 12VDC coil, it will automaticly set a pilot value based on voltage. Example 30A pilot on L2 and 12A pilot on L1. Note this feature is not avaliable if other hardware in the EVSE has a fixed voltage requirement.

(2) It may fit but it will be really tight. A 75A contactor will have a fixed voltage requirement as the coil is 240VAC so (1) will no longer apply and the EVSE will be L2 only.

Great!! thank you. I've been out for the RSA conference and am trying to do catch up here. I have re-scheduled the install of the finished 75Amp EVSE for Monday 3/4.

Have anyone charged their S85 with the 75Amp OpenEVSE and noticed any sign of overheating on the OpenEVSE? I would appreciate your advise on whether I should cut a hole on each side of the box for ventilation (total two holes).

I would like to build a portable EVSE that supports 40Amp feed. However, I am not willing to go through all the cuttings for a bigger box. Therefore, I think I will wait a little bit to see if the genius OpenEVSE team designs/builds an OpenEVSE support the 40Amp feed in the exiting box. If all fails, I will tell Darren to do the 30Amp portable OpenEVSE.

 

[mitch672]

Have anyone charged their S85 with the 75Amp OpenEVSE and noticed any sign of overheating on the OpenEVSE? I would appreciate your advise on whether I should cut a hole on each side of the box for ventilation (total two holes).

Waidy, my 75A OpenEVSE is the one on the OpenEVSE Wiki, I charge my P85 Model S (with dual chargers) with it all the time, it does not get warm or hot. I should also mention that I took delivery on January 17th, and the temperature in my garage hasn't gone above 35-40 degrees F since then, so I can't say for sure how it will work in sunny warm California. I have had the contactor enabled inside my 70 degree house for multiple days while I was testing the 75A OpenEVSE, and the contactor barely got warm. I also measured the contactor coil current, and it was 1/10 of an amp, so I don't think you'll have any issues, simply not enough wattage (24 watts) to worry about.

 

[waidy]

Have anyone charged their S85 with the 75Amp OpenEVSE and noticed any sign of overheating on the OpenEVSE? I would appreciate your advise on whether I should cut a hole on each side of the box for ventilation (total two holes).

Waidy, my 75A OpenEVSE is the one on the OpenEVSE Wiki, I charge my P85 Model S (with dual chargers) with it all the time, it does not get warm or hot. I should also mention that I took delivery on January 17th, and the temperature in my garage hasn't gone above 35-40 degrees F since then, so I can't say for sure how it will work in sunny warm California. I have had the contactor enabled inside my 70 degree house for multiple days while I was testing the 75A OpenEVSE, and the contactor barely got warm. I also measured the contactor coil current, and it was 1/10 of an amp, so I don't think you'll have any issues, simply not enough wattage (24 watts) to worry about.

Thank you thank you!! I don't like cutting.

 

[waidy]

Does any one uses or knows of a date-storage-meter with the EVSE? My objective is to gather data per charging session per EVSE on charge time (start,end) and kWh juiced. I have TED which does not give me the precise information I need. The E-monitor requires subscription (Yikes). I wonder what kind of meter ChargePoint and Blink use.

 

[garygid]

Look at these
http://www.powermeterstore.com/c112/measure_power_at_the_plug.php?gclid=CIWakZDk4LUCFQP0nAodszYA5w" onclick="window.open(this.href);return false;

Here are some electronic watt hour meters that can be used for monitoring:
http://www.ekmmetering.com/?gclid=CMid8_7k4LUCFQyEnQod_DQAMg" onclick="window.open(this.href);return false;

 

[waidy]

Look at these
http://www.powermeterstore.com/c112/measure_power_at_the_plug.php?gclid=CIWakZDk4LUCFQP0nAodszYA5w" onclick="window.open(this.href);return false;

Here are some electronic watt hour meters that can be used for monitoring:
http://www.ekmmetering.com/?gclid=CMid8_7k4LUCFQyEnQod_DQAMg" onclick="window.open(this.href);return false;

Good find! Thank you.

I already have half a dozen of killawatts. The problem I have with killawatt is that it requires "discipline" (I have to look and record every charging session, which I lack :-(). However, it is a good product as it has helped me finding the vampire load on various appliances and electronic equipments.

The EKM meter works pretty much like the TED5000 I have but the reporting is much much better. It also seems CT, meter, icloud usage, push-data-box are a-la-carte. I will look at it some more. Thanks for the referral URLs.

 

[garygid]

This $90 EKM basic meter is for manually reading, which you want to avoid:
http://www.ekmmetering.com/ekm-metering-products/electric-meters-kwh-meters/basic-kwh-meter-100a-120-240-volt-3-wire-60hz-ekm-25ids.html" onclick="window.open(this.href);return false;

This $140 meter has remote reading and thus logging capabilities
via an RS-485 bus to a computer.
http://www.ekmmetering.com/ekm-metering-products/electric-meters-kwh-meters/single-phase-energy-meter-for-120-240-volt-3-wire-60hz-ekm-25ids-nv2.html" onclick="window.open(this.href);return false;

These are smaller than they appear, and one might be able to place
either inside the OpenEVSE enclosure.

As I recall, one can run the RS-485 a long way, and get an adapter
that changes the 485 voltages to Serial RS-232, and then use a
Serial-to-USB adapter to feed the data into the computer.

Or, use their $20 RS-485 to USB adapter:
http://www.ekmmetering.com/ekm-metering-products/remote-meter-reading-solutions/ekm-usb-to-rs-485-converter.html" onclick="window.open(this.href);return false;

It appears that their $30 (one time, with a free 30 day trial) EKM dashboard
might do the Logging that you are wanting:
http://www.ekmmetering.com/ekmdash" onclick="window.open(this.href);return false;

In years past, these EKM people seemed good to work with.

 

[garygid]

They seem to have a pretty good tutorial:
http://www.ekmmetering.com/information/the-complete-guide.html" onclick="window.open(this.href);return false;

 

[waidy]

Dear GaryGID. Thanks for the product recommandation and it saves me a lot of reading time. This is really good information. The photo has a pair of what it looks like a low voltage power wires. The installation instruction does not say it needs to be connected. Do you know by any chance whether the $140 EKM-25IDS-N unit needs to be connected to a low voltage power source? Is there a power pin inside the OpenEVSE I can tab the $140 meter. My electrician is coming tomorrow so it's a good time to add if the lower voltage is needed.

 

[garygid]

No low voltage is needed to power the meter.
It takes its power from tapping the lines that pass through,
which it also uses to read the voltage to multiply by the amps
to get power measurements.

To avoid pollution of this OpenEVSe thread, I have started:
http://www.mynissanleaf.com/viewtopic.php?f=26&t=11776" onclick="window.open(this.href);return false;

I have downloaded the EKM Dash software and I am monitoring
one of their demo meters now.

CU on the new thread.