OpenEVSE Charging Station any Users?

Discussion about EV/Battery charging infrastructure, Electric highways etc.
doug
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Re: OpenEVSE Charging Station any Users?

Post by doug »

Hi,
I am building a couple of OpenEVSEs. The first is an early board from an old relay kit bought years ago, but never finished. I just bought a Kona, so also bought a new (advanced) kit for it.
I am changing to TOU metering at home, so need to set up the charging for both the Imiev & the new Kona.
So, the old kit will go into the OpenEVSE box. I will use a 240v contactor powered by a small SSR. (because the old board does not have AC output) I have a recycled Outlander lead for this.

The new kit will be built into an Oxbro case (from Perth, manuf in South Africa). The OKO-OC case is about the same size as the OpenEVSE case, but high enough to fit a socket in the end. Base made from GRP, so strong. These cases are about $70, so not cheap.
doggy
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Re: OpenEVSE Charging Station any Users?

Post by doggy »

From memory, my box was a sealed waterproof ABS box from RS components and cost about $100. So your $70 is a good price. My Type2 connector mounts on the face plate. There is not much in the way of spare room. Still going strong and the box is very sturdy.
Good luck with it all.
Best Regds,
Dave
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Re: OpenEVSE Charging Station any Users?

Post by reecho »

I see you are getting an Iotawatt kit soon Doug. Me too. Looking forward to it.
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jonescg
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Re: OpenEVSE Charging Station any Users?

Post by jonescg »

doug wrote: Sun, 12 Jul 2020, 08:37 I just bought a Kona,
Well that's a step up from the iMiEV! Well done mate!
AEVA National Secretary, WA branch chair.
doug
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Re: OpenEVSE Charging Station any Users?

Post by doug »

Update:
currently stuck in Brisbane for another 2 weeks due to grandparently duties for our just born granddaughter. Luckily, I brought my computer!
I picked up the 2 Oxbro cases: Plenty of room in the Fibreglass base. (they are molded from paste, so not hand laid). The top is high, & I might have been able to use a lower lid.
Currently waiting on parts. I intend fitting a type ´B´ ELCB inside the case for safety. I have also ordered some TTP223 touch switches that I should be able to add to the Kit. (The type that is jumperable for active low output is needed. abt 50c ea from China) I noted the OpenEVSE touch switch has a switching transistor (buffer) that I do not think is necessary, but I will know when I try it! I have also programmed up an ESP8266 board as a WFI interface for the old EVSE. The old EVSE board will have an external SSR to drive the 240v contactor, instead of the original 14v relays. Contactors are more reliable. My box will be strong enough to fit the EVSE cable socket without extra support.
I will post some pictures, etc when construction begins. (This could be a resource for other builders)
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Re: OpenEVSE Charging Station any Users?

Post by smithy2167 »

I'm awaiting arrival of an OpenEVSE kit and thinking about 3-phase and charging from available PV. We have a 3-phase house, 3-phase solar and 3-phase car (Zoe) so the question arises, should I build a 3-phase version of the OpenEVSE?

One thing I have read is that the J1772 interface only allows a minimum charge current of 6A. I assume that is "per phase" so, for a single phase charger, would be ~1.4kW but for a 3-phase charger, would be ~4.2kW. Is that correct? The solar system is 10kW, but there are days when it doesn't generate all that much. If the minimum charge rate is 4.2kW, and the OpenEVSE doesn't stop charging when solar output drops (does it stop eventually?), I can see days when a lot of charging power is being drawn from the grid.

So, 3-phase would be good as it will be a portable setup plugged in to a 3-phase outlet in the garage. Plus it would be nice to have the ability to do a 22kW quick charge for fast turnaround. However, if it's going to cost more to run and have only a little benefit over a single-phase 7kW unit, then I'm not so sure.

Another thought is a configurable 1/3-phase setup. I notice that @doggy has the original contactor plus a separate 2-pole contactor to switch the other 2 phases. If the switching of the second contactor could be separately enabled/disabled with a "switch" in the software, then 1 or 3-phase operation should be possible. That software switch could also adjust the scale factor for 1/3 phase. Does that sound reasonable?
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jonescg
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Re: OpenEVSE Charging Station any Users?

Post by jonescg »

The 3-phase option is a good choice for travelling long distances, as you can pretty much fill the car in 2 hours. But it is bulky and heavy.
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doggy
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Re: OpenEVSE Charging Station any Users?

Post by doggy »

It is correct that the 6A is per phase. What I have done is put a three phase 32A plug on the OpenEVSE. I have made adaptor cables as follows:

Single phase 32A plug (L1 only) to three phase connector.
15A plug to three phase.
10A plug to three phase.
16A single phase "Commando plug" to three phase (fpor caravan parks).
J1772 to L2.

Be warned that 6A single phase charging with Zoe is not worth it (too inefficient). In poor insolation conditions, I do better collecting the excess in lithium batteries and then running a 5kW inverter back to the car.

I do not bother to deactivate contactors. For single phase, only L1 is presented to the Zoe. You could certainly selectively switch off phases if you wanted to. From memory, I am driving one contactor from 12V DC and the other one from AC off the uP. That is standard in the OpenEVSE firmware.

I have been getting around to modifying the software as follows:

a. The current firmware assumes L1 is 120V, I am going to change that to be single phase 230V. Changes are pretty simple.

b. Allow the 6A minimum to be configurable, just as the max is configurable. the unit is almost out of uP memory so I am not certain this will fit. But maybe it will.

c. I would like to change the solar excess programming which currently leave too much head room (about 150watts). I would rather it was close to zero. I have 16kWHrs of batteries and my variable current chargers can track at about +-10watts at 3.5kW with the excess solar. I would like OpenEVSE to be similar.

I will evebtually get around to these changes. In the meantime, I just mentally divide by three for the kWHrs.

My OpenEVSE is my "go to" charger both at home and away. Our garage is down 60 stairs and I can sit in my study controlling it and checking status over WiFi.

Regds,
Dave
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