DIY charge point

[Glan gluaisne]

The defined states in the standard are that the CP should sit at +12 VDC when in State A, the idle state when it's not signalling any power availability to the car. The car charger will load this down to the plugged in voltage, of +9 VDC, and should then just sit doing nothing until the 1 kHz pilot comes up. At that time, the car charger should acknowledge the availability of power and load the positive going side of the CP signal down to + 6V (leaving the negative going side at -12 V).

The correct way to implement a timer function would be to hold the CP at +12 VDC, with a 1 k source impedance. I know that the Tesla charger works fine (now) with this, and will wake up as soon as the 1 kHz pulse train turns on. My charge points all have time switches, set to the E7 off peak period, and those time switches all just signal the charge point to sit at +12 VDC (before the 1 k source resistor).

 

[pdk42]

The defined states in the standard are that the CP should sit at +12 VDC when in State A, the idle state when it's not signalling any power availability to the car. The car charger will load this down to the plugged in voltage, of +9 VDC, and should then just sit doing nothing until the 1 kHz pilot comes up. At that time, the car charger should acknowledge the availability of power and load the positive going side of the CP signal down to + 6V (leaving the negative going side at -12 V).

The correct way to implement a timer function would be to hold the CP at +12 VDC, with a 1 k source impedance. I know that the Tesla charger works fine (now) with this, and will wake up as soon as the 1 kHz pulse train turns on. My charge points all have time switches, set to the E7 off peak period, and those time switches all just signal the charge point to sit at +12 VDC (before the 1 k source resistor).

Thanks. That is what I gleaned from the IEC spec. But this is what QUBEV are suggesting:

Crude - but will it work?

 

[Glan gluaisne]

It's anyone's guess whether it will work or not. The car charger may choose to accept it, or may just throw a wobbly because it thinks that the plug latch has failed (plugged in with no CP = possible latch error as the car thinks the plug isn't really there, perhaps?). The protocol controller may or may not behave with the CP plugged in load recovered, it's not something I've tried.

A better way to do this would be to perhaps swap out that Rolec protocol controller for a Viridian one and then use the IC terminal to set the CP to State A. It may be that the protocol controller is badged Rolec, but is really a Viridian special, as Rolec were using Viridian/Mainpine controllers at one time. The Viridian/Mainpine controller has a current set terminal, IC, that has a resistor to ground to set the charge current. This also gracefully shuts down the controller, setting the CP to +12 VDC, when the resistance goes out of the acceptable range, so a time switch can take advantage of this to switch the charge point on and off.

It would be interesting to know what that protocol controller is, and whether one of the other terminals allows it to be gracefully shut down, or whether it has the IC terminal hidden somewhere under the cover.

 

[NickM157]

Came upon your post when looking for information on the Viridian 2.0 and building ones own charge point. Have found it very useful especially with the addition of the test box. As you have knowledge of the regs and best practice could you consider giving some guidance please.

The Viridian 2.0 gives earth protection so no earth rod is required which helps with the installation. Will be putting a new CU just for the charge point. This will take its supply from Henley blocks already installed between meter and house CU, also coming off the Henley blocks are a CU for separate supply to loft conversion. My question/s are:-

I am wanting / considering fitting the charger CU with an RCBO 32A rather than seperate MCB and RCD. Does the charger CU need to have an incomer switch?
Should one be considering fitting a surge protector into the charger CU?
Should one be considering fitting an AFDD into the charger CU.

Any discussion / guidance would be much appreciated

 

[Glan gluaisne]

Came upon your post when looking for information on the Viridian 2.0 and building ones own charge point. Have found it very useful especially with the addition of the test box. As you have knowledge of the regs and best practice could you consider giving some guidance please.

The Viridian 2.0 gives earth protection so no earth rod is required which helps with the installation. Will be putting a new CU just for the charge point. This will take its supply from Henley blocks already installed between meter and house CU, also coming off the Henley blocks are a CU for separate supply to loft conversion. My question/s are:-

I am wanting / considering fitting the charger CU with an RCBO 32A rather than seperate MCB and RCD. Does the charger CU need to have an incomer switch?
Should one be considering fitting a surge protector into the charger CU?
Should one be considering fitting an AFDD into the charger CU.

Any discussion / guidance would be much appreciated

Glad you found this discussion helpful.

All that's needed for protection on the supply cable to the charge point, if using any charge point that has integral open PEN protection and DC tolerant earth leakage protection, is over-current protection (sized for the cable supplying the charge point) and residual current protection (Type A) to both protect the cable and provide the required manually resettable fault protection. An RCBO can provide both functions in a single unit, either a 40 A or 32 A double pole, or single pole +N, RCBO would do that job OK. No need for a separate DP isolator switch as long as the RCBO switches both the live conductors, L and N.

Whether surge protection and arc fault protection are desirable is debatable. Car chargers have pretty good built-in surge protection, but if you live in a rural area, where voltage spikes and disturbances might be more common, then it perhaps makes sense to add surge protection. If this is included in the smaller CU supplying the charge point, then the SPD and its associated MCB will provide surge protection for the whole installation, as long as the length of the tails is kept short.

Arc fault detection is, IMHO, an expensive, and arguably far less useful addition. The nature of the way a charge point works makes it unlikely that there could be a fault that might trigger an AFDD. The usual reasons for arcing are things like loose cable terminations, loose or damaged plugs and sockets, loose or damaged fuse holders and, perhaps, damaged thermostats and heating controllers (the latter are in my experience most likely to cause some arcing). I've been following some people that have been doing practical tests on AFDDs, and frankly the results don't seem at all encouraging. Right now, I'd not yet consider fitting an AFDD on a charge point circuit, and until their performance improves, and their price comes down, I'd not consider fitting one on any household circuit. I'd rather just make sure the installation is regularly inspected and tested.

 

[phil4]

I hope no one minds, but can I ask about Viridian EVSE installation? The unit comes with 2 inputs, labelled as N & L, and three outputs, labelled as PE, N & L.

the inputs go through a Type-A RCD, and off into some electronics (presumably the DC and PEN protection bets), and then into a contactor. There's an earth coming from the top of the enclosure, to through to the contactor and out to the PE.

So my question... I thought I'd heard that the earth for the charging point should be kept separate from the "house" earth... if doing so, where does the earth for this Viridian unit come from?

I've taken the house earth and put into the top of the enclosure, which then goes through the electronics and contactor and onto the charger... seems to work. Without doing that the charger wouldn't work and complained of not having an earth.

Did I get that wrong?

 

[Glan gluaisne]

I hope no one minds, but can I ask about Viridian EVSE installation? The unit comes with 2 inputs, labelled as N & L, and three outputs, labelled as PE, N & L.

the inputs go through a Type-A RCD, and off into some electronics (presumably the DC and PEN protection bets), and then into a contactor. There's an earth coming from the top of the enclosure, to through to the contactor and out to the PE.

So my question... I thought I'd heard that the earth for the charging point should be kept separate from the "house" earth... if doing so, where does the earth for this Viridian unit come from?

I've taken the house earth and put into the top of the enclosure, which then goes through the electronics and contactor and onto the charger... seems to work. Without doing that the charger wouldn't work and complained of not having an earth.

Did I get that wrong?

The confusion, perhaps, comes from the need to keep earthing systems separate if they are of a different type, for example if the installation is TN-C-S/PME, where the protective earth is combined with the neutral on the incoming cable, and if the charge point is then wired as TT, so has an earth electrode for its protective earth, then not only must the charge point protective earth not be connected to the supply protective earth, but there must also be adequate separation (typically 2m) between exposed conductive parts that may be connected to the two different systems. An example might be an outside tap or metal pipework that's connected to the PME earth and a nearby charge point that is earthed via its own electrode - the two have to be separated.

If any sort of open PEN fault device is used, including the Viridian Mk 2 module, then the PME protective earth is used as protection for everything. In the case of the Viridian Mk2 unit, then there are two separate contactors, one to switch the line and neutral to turn power on and off to the car, the other (which is normally always on) that connects the PME earth to the car. In the event of an open PEN fault, the earth contactor opens to make sure that the car body doesn't rise to a dangerously high voltage. This is similar to the way devices like the matt:e and ecoharmony open PEN boxes work, they also disconnect the PME earth from the charge point if there is a fault.

In normal use, the protective earth from the supply comes into the charge point, is connected to the earth contactor, with a small current sensing transformer around it, which forms a part of the open PEN protection system. The protective earth to the cable running to the car comes from the switched side of the earth contactor. The photo below shows this earth contactor at the far right, with some annotations added that might make things clearer:

 

[phil4]

Thanks for exposing, all makes sense now.

thank you.

 

[NickM157]

Many thanks for the advice, shopping list nearly complete.
This then brings me to another question, if just using a 2 pole RCBO does this have to be housed in a metal CU (17th & 18th edition regs?) or can a plastic one be used.
Oh and one last question. i have not finalised in my mind whether to go for tethered or free. Space down driveway with plug sticking out from the wall, esthetics etc . I will be using the Viridian EPC Mk2 + PEN (arrived this week), but can not understand the proximity connection. There is no explanation in the downloadable handbook. Is it an input or an output to the EPC. Have looked at the 'openev basics of the J1772' but still can't work it out. Other Googles suggest a resistor is required but no value given. Was this just for the EPC Mk1? If one was to go for the free but later change to tethered would this mythical resistor have to fitted or would the DIP switches on the EPC MK2 negate this?

 

[Glan gluaisne]

Many thanks for the advice, shopping list nearly complete.
This then brings me to another question, if just using a 2 pole RCBO does this have to be housed in a metal CU (17th & 18th edition regs?) or can a plastic one be used.
Oh and one last question. i have not finalised in my mind whether to go for tethered or free. Space down driveway with plug sticking out from the wall, esthetics etc . I will be using the Viridian EPC Mk2 + PEN (arrived this week), but can not understand the proximity connection. There is no explanation in the downloadable handbook. Is it an input or an output to the EPC. Have looked at the 'openev basics of the J1772' but still can't work it out. Other Googles suggest a resistor is required but no value given. Was this just for the EPC Mk1? If one was to go for the free but later change to tethered would this mythical resistor have to fitted or would the DIP switches on the EPC MK2 negate this?

Depends where the small CU is located, but either way a metal one makes sense, as it's more robust to terminate SWA to a metal CU than a plastic one.

The main function of the proximity pilot, apart from being another safety provision, is to signal to both the car charger and the charge point what the cable current rating is, when using a non-tethered arrangement There are resistors at both ends of a charge cable, inside the connectors, connected between the PP and ground, and both the car charger and the charge point check the value of these resistors to ensure that the cable current rating isn't exceeded. If the unit is connected to a tethered cable then the PP function isn't used and the unit just uses the current set by the resistor from IC to ground, as a maximum.

 

[NickM157]

Have not had much success sourcing 32 A DP contactors 1 module wide, you mentioned TME.eu but they are not taking any UK orders for the next couple of weeks until they implement a new ordering system that can cope with having to charge the import duties because of us leaving the EU. They seem to be the only people that supply Iskra that I can find. BG does a contactor but that is two modules wide.

 

[Glan gluaisne]

RS seem to do this one that would fit the bill, although more expensive than TME: CN3220220 | Lovato 2 Pole Contactor - 32 A, 220 → 230 V ac Coil, 2NO | RS Components

Ilecsys also sell the same unit: Lovato Single Module, 2 Pole, Modular

 

[NickM157]

RS contactors are out of stock until early March. Succes have managed to start an order with TME.
I have been trying to match the box you have used for the test box. From your post it was one you had lying around but can you remember whose make it is. The layout is just right, what size is it. Many thanks.

 

[Glan gluaisne]

Great that TME are OK with selling to the UK again, I've used them a few times now and found them to be very good.

The box I used was one I had lying around for years, an IP66 GRP box that I'm sure came from RS at some time. It's overkill in terms of mechanical strength, as it's pretty heavy duty. It's 160mm wide, 260mm high and 95mm deep and was probably pretty expensive (I think I "liberated" it . . . ). I've built other charge points into these caravan hook up enclosures, that are pretty much ideal for the job, and have a clear window through which the status LED on the Viridian module can be seen: IP65 MCB, RCD Enclosure,Caravan Hook Up, consumer unit enclosure,adaptable box 660042416391 | eBay

 

[Glan gluaisne]

Time for another DIY charge point build, this time in readiness for the arrival of my wife's Renault Zoe in a few weeks time. She parks at the opposite end of the drive, around 40m from the house, and next to our garage. When I built the house I fitted a charge point just inside the garage door, really as a back up, but it was completely home made (using a PIC microcontroller and home made circuit board for the control stuff). Because the Zoe has its connector under the front badge, and because we didn't want to faff around opening the garage door to get at the lead, I decided to fit a charge point on to a 4" x 4" timber post, right next to the drive.

I thought it might be useful to try and document a budget DIY installation, using off-the-shelf components, that anyone who's reasonably competent with electrical work, and who has access to the required test equipment, could build. Our requirements were for a small charge point, not much wider than a 4" fence post, that would allow timer controlled charging, with a selectable option for either off-peak, cheap rate, charging, or a charge immediately option, no matter what the cost.

I opted to use the cheapest Viridian EVSE protocol controller, as I know that Viridian units are well-designed, plus they are easy to use, and allow the charge current to be easily set (or changed) and also allow fully IEC 61851 compliant on/off control. It's a "dumb" unit, and pretty near foolproof. Adding a time switch allows simple peak/off-peak switching, but does mean making the unit slightly larger than it needs to be (it's ~110mm wide, could be ~85mm wide without the time switch).

Because the garage is a fair distance from the house, it already has an earth electrode and was wired as a TT installation. That made things simpler, because all I needed to do was rearrange things in the garage consumer unit and swap the existing Type A RCD for a slightly larger Type B RCD. The new charge point is about 3m from the garage, with a ~6m run of cable from the garage consumer unit, so about as easy as it gets. This is a photo of the garage consumer unit, after being re-arranged to take the Type B RCD, and with the new charge point cable installed:

The new charge point was built into a Wylex WBE4 IP65 enclosure, and although things were a bit tight when it came to dressing the incoming 6mm² NYY-J cable neatly inside, it all fitted OK:

I completed the installation and testing this afternoon, took around a couple of hours to wire the unit up and make up a Type 2 lead for it. This is the finished installation:

I'm pretty pleased with the way it's turned out, although would have preferred a black enclosure, I think. It's small enough to not really look too out of place, though.

The cost, not including the 4" post and concrete, breaks down like this:

Wylex WBE4, 4 module IP65 enclosure: Wylex WBE4 Enclosure 4Mod IP65 ~£19

(the smaller enclosure is this one: https://www.screwfix.com/p/wylex-3-module-ip65-insulated-enclosure-with-visor/74436 ~£11)

Viridian EPC module: Viridian EV EVSE Protocol Controller Tethered 16A/32A ~£78

32A DP contactor: https://www.tme.eu/gb/details/ika232-20_230v/contactors-installation-modular/iskra/30-046-833/ ~£12

Greenbrook single module time switch: Greenbrook DIN Rail Time Switch (T80-C) | CEF ~£16

6m of NYY-J cable ~ £20

5m of 32 A European made, high quality, charge point cable ~£45

32 A Type 2 connector ~£75

Type B RCD ~£114

40 A MCB ~ £4

Connector holster and cable hook ~£15 (eBay)

Cable cleats, screws, waterproof switch, Wago connectors, etc ~£10

The total installed cost, excluding my labour (she's promised me a nice bottle of single malt for that) came to about £408, out of which the actual cost of the components for just the charge point, tethered cable and connector came to about £250. The cheapest ready built tethered charge point I've been able to find is about £390, and is more than twice the size of this one.

The cost and size could be reduced a bit by not bothering to fit the time switch. The cost for a version without the time switch and peak/off-peak switch would cost around £224. That's probably about as cheap as it's possible to build a charge point that still uses reasonably good quality components.

Perhaps worth noting that, because the garage was already wired as a TT installation, there was no need to add the £30 to £40 it would have cost to install an earth electrode. The only major installation related addition was the cost of the Type B RCD, at £114. Some charge points have this level of protection built in, so only need a ~£20 Type A RCD, but they tend to be charge points that sell for around three times the price of this unit.

 

[HenryT]

The total installed cost, excluding my labour (she's promised me a nice bottle of single malt for that) came to about £408, out of which the actual cost of the components for just the charge point, tethered cable and connector came to about £250. The cheapest ready built tethered charge point I've been able to find is about £390, and is more than twice the size of this one.

Nice work GG.

So it'll be virtually free once you claim the grant then, eh?

 

[Glan gluaisne]

Nice work GG.

So it'll be virtually free once you claim the grant then, eh?

If only!

 

[rdav89]

There's some fantastic info in this thread so thanks very much to everybody sharing.

I'm looking at putting together a charge point very similar to those in this thread based around the Viridian EPC 2.0. I was wondering if anyone could help with a few questions.

Firstly, the EVSE is to be 'Free' (non-tethered) but I am looking at having the socket outlet in a smaller, separate enclosure 4-5m away from the EVSE. I've seen 'EV Ultra' cable used in some builds which includes a Cat5e data cable. Would this be capable of carrying the PP and CP signals along with 12V for lock and LED output from the EPC? I would prefer a single cable between the two units rather than have to run a separate cable to power the LEDs and lock at the socket outlet.

Has anyone managed to get any sort of authentication system to work with the Viridian EPC such as RFID access? Viridian have informed me this can be done using the IC and 0v terminals but as of yet haven't been able to provide further information. As I understand it, connecting the IC and 0V directly would force the EVSE into state A, preventing charging until the resistance is changed. I presume I would need a microcontroller that can change the resistance value depending on whether a RFID card is detected? Or is there a simpler way to control this? I was hoping something might be built-in to the EPC using the 'impulse' feature that is mentioned in the manual.

Lastly, anybody had any success making a Viridian EPC 'smart'. If this is achievable then perhaps it would be possible to pursue the OLEV grant even for a DIY charger...

 

[Somex]

In this thread: External Garage - Charging

I mentioned that I was building a new DIY charge point, using off-the-shelf parts. Rather than take that thread off topic, I thought I'd start a new one, although I fully accept that not many are likely to be that interested in tinkering like this.

In that other thread @LukeUK wrote this:



and @dakaix wrote this:




I've opted to try out the new Viridian EVSE module: EVSE Protocol Controller 2.0 (EPC 2.0)

This comes with open PEN detection for £124.80 (inc VAT), and for another £50 plus VAT also includes the same DC leakage protection device I'm already using with my home brew charge points, the Western Automation RCM14, so has the required DC leakage current protection, so only needs a suitably rated Type A RCD or RCBO upstream, and doesn't need an earth electrode.

Other parts needed are a couple of 32 A contactors (I'm using a couple of Iskra ones I happen to already have as spares, but they are only about £12 each, inc VAT (see here: 30.046.833 ISKRA - Contactor: 2-pole installation | 32A; 230VAC; NO x2; DIN; IKA232-20/230V | TME - Electronic components), plus some DIN rail contact blocks, some short lengths of 6mm² wire for internal connections and ideally some cable ferrules and crimp tool to make the wiring neater. The whole thing would easily fit in something like an empty garage CU box.

Because I need E7 off peak switching, I'm adding a DIN rail time switch to control the Viridian EVSE, plus I'm also adding variable current settings, plus the option to turn the charge point off, or run it only during the off-peak E7 period. Adding that extra functionality adds maybe £20 to the cost.

BTW, my reason for doing this is partly fun, and partly to remove my homebrew PIC based charge points with code I wrote years ago. They work fine, but use GPS modules to control the time switch function and rely on code I wrote years ago, and which I've modified a few times over the years. As I get older I'm trying to replace my homebrew controls with off-the-shelf stuff, that's properly documented, so that others have at least some chance of maintaining or repairing it in future.

Plus 1 for Viridian kit
The guys at eco harmony (Viridian sales outlet) are helpful as well