Open source EV chargepoint schematic

[Faringdon]

Hi,
Do you know where we can get the free download EV chargepoint schematic? Ive heard so much about it, but cant find it anywhere.
There is an open source chargepoint somewhere, but where , we dont know?

[Phoenix]

There is openEVSE with schematics on github.

[Faringdon]

Thanks yes, it seems to be here
https://github.com/OpenEVSE/OpenEVSE_PLUS

...i am fishing around to see what they do for Type B RCD, inclusing the DC 6mA detection....or do they buy in a (always expensive)  RCD module?

[NiHaoMike]

The GFCI has self test capability so it can be made immune to DC in firmware - regularly self test and just trip the circuit if it fails.

[Faringdon]

Thanks, the thing is, the trip needs to happen within 900ms of the DC fault happening, so self test cant be used for this unfortunately.....unless you self test every 100ms or so.....but that seems excessive?

[NiHaoMike]

At the cost of higher complexity, you could have the self test be continuous using a higher, non harmonically related frequency at a few hundred Hz to a few kHz. You can then do testing to find out how much DC bias it takes to compromise the sensitivity to AC ground faults and make sure the self test signal would drop below acceptable levels well before that point.

[uer166]

The GFCI has self test capability so it can be made immune to DC in firmware - regularly self test and just trip the circuit if it fails.

That's not how those work at all, please don't post advice that's regulatory-related if you don't have a clue. I'm not gonna go into the details because it's a waste of time with Treez, but just want to make 100% clear that this is insufficient.

[mikeselectricstuff]

The EVSEs that I've had apart use something like this for DC RCD sensing
http://www.magtronworld.com/datasheet/zb_users/upload/2017/11/201711151510713677614896.pdf

[uer166]

Thanks yes, it seems to be here
https://github.com/OpenEVSE/OpenEVSE_PLUS

...i am fishing around to see what they do for Type B RCD, inclusing the DC 6mA detection....or do they buy in a (always expensive)  RCD module?

Type B: detects DC leakage, AC leakage including 50/60Hz, half-wave rectified leakage, as well as high frequency (up to many kHz IIRC). The ones I know of have a full-featured fluxgate core sensor, and yes they cram in an entire offline PSU, analog/digital controller with relatively complex circuitry in a DIN rail mount unit.

In EVSE world, the cheapest way is a dedicated type A RCCB, with an EVSE-integrated 6mA DC leakage protection, usually according to IEC-62955; the device is called a RDC-DD and also usually uses a fluxgate such as https://www.bender.de/fileadmin/content/Products/d/e/RDC104-4_D00402_D_XXEN.pdf. The vast majority of EVSEs out there don't comply with their ratings and are CE certified, so don't look too hard at units unless they've been 3rd party certified by VDE or CSA or whoever.

You can't "just self test" the DC sensing out of it because you're actually protecting the upstream type A RCCB/RCBO from being blinded by the 6mA DC leakage, as opposed to making something inherently immune to DC leaks. The IEC62955 standard also has plenty of clauses that prescribe stuff about what to actually do in case of a DC leak, simply opening power relays is insufficient if you care about complying with that specific standard, which is itself technically not a hard requirement.

Treez, just buy a type B, or a type A + integrated 6mA DC leakage detector if you want at least some safety for the end user. Yes, they're $200+, and no, you won't be able to make it cheaper.

[Faringdon]

Thanks,
Though i am wondering if we can do something like the following for the RCD-DD...?

https://repositorio.ufmg.br/bitstream/1843/37430/2/Design%20of%20a%20Low-Cost%20Residual%20Current%20Sensor%20for%20LVDC%20Power%20Distribution%20Application.pdf

.....Its a $5 RCD-DD. I got the link from the OpenEVSE website.

Then we could make our own 15-30mA imbalance detector aswell.
____----_____
As we all know, Standards must be obeyed.....though it does seem a terrible waste of time to have people making electronics thats no use, and just causes loads of false tripping and resultant relay lifetime shortening.

I wonder if its worth doing a "referendum" on this.....for each individual country...because getting DC in the mains is pretty well impossible to occur....and if it did.......its detection would in fact be perfectly good with a Type A RCD and a current loop(s)  going through it......every now and then injecting an imbalance current and seeing if it detected it or not..(if it didnt then theres DC present)...like NiHaoMike kindly sugested

The only real way you can get DC in the mains from an EV  charger, is if that EV had been involved in like  a "train crash" type accident...then someone hoists it up and takes it to a garage or whereever...and then someone plugs in its charger......even then you woudlnt be garanteed to get dc in the mains.

So you could have a test as described at start up..then frequently  tests thereafter.

The western world needs all the electronics capability it can get right now.........(producing anti drone guns for u-know-where, etc etc)....so having jobs that "dont need doing" seems very poor.

[mikeselectricstuff]

Treez, just buy a type B, or a type A + integrated 6mA DC leakage detector if you want at least some safety for the end user. Yes, they're $200+, and no, you won't be able to make it cheaper.

Much cheaper than that : https://www.aliexpress.com/item/1005003085547942.html
I've looked at one of these and it seems fine.