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.