AC EV chargers, technical details and non-standard supply arrangements - Page 1
Forum section: electronics / general

author: richard.cs
author_rank: Super Contributor
timestamp: October 22, 2018, 09:39:54 am
content: So, in the UK most of our charging points are one of:1 phase @ 16 A (3 kW)1 phase @ 32 A (7 kW)3 phase @ 32 A (22 kW)3 phase @ 63 A (43 kW)In much of Europe 3 phase @ 16 A (11 kW) is also pretty common.But it's rather unclear to me what other combinations are supported by both the standards and the cars, and what exactly happens if you have a different combination. I've seen it stated that an IEC 62196 Type 2 connector is rated at 80 A single phase, up from 63 A for 3 phase, which kind of makes sense as only 2 pins are getting hot instead of three. The signalling standard supports 80 A, but I have never seen a single phase charge point at over 32 A even though in the UK single phase supplies of 100 A are the norm. I think some Teslas support a high current single phase AC mode?So if you gave a car a single phase supply and set the signalling for 80 A what does it do? Let's say it's designed for 43 kW 3-phase charging @ 63 A per phase like a rapid-charge Zoe, does it draw 63 A on one phase? Does it draw 80 A because the limiting factor for the charger is not the input current? Does it sit and sulk at 32 A because that's the highest the designers expected for single phase? What happens if you give it single phase between L3 and N with nothing on L1 and L2?If you connect the same phase to L1, L2 and L3 is the car smart enough to keep the neutral current down to the signalled level or does everything go up in smoke? What about if you connect two phases of a three phase supply - does that just work as expected at 2/3 power? What if you make those two phases 180 degrees apart, does it work or go bang from the increased phase-phase voltage?I have a suspicion that the charging standards will cover some of these cases, but that most will be up to the vehicle manufacturer and probably not publicly documented to this level of detail.

author: free_electron
author_rank: Super Contributor
timestamp: October 26, 2018, 01:36:48 am
content: It depends on what car and what charger...Tesla has a 3 phase charger for europe and a 2 phase for US. The charger eats anything from 110 single phase , 110 v two phase (220 volts with centertap) to 3 phase in star or delta.For fixed charging points the base station knows how they are wired and communicate to the car what the on-board block needs to configure for and how much power it is allowed to pull.For mobile charging cords the end connector adapter lets the charger know what kind of outlet it is plugged in and what the on-board charger needs to do. depending on what kind of outlet you plug the mobile connector you click-on a different socket adapter. that adapter has an id-chip that lets the charger know what it is plugged in to so it can configure for current and voltage and phases.Supercharging is different as that is a DC base station bypassing the on-board charger completely. The battery management computer talks directly to the supercharger and the decide optimum power point and charge curve. During ramp-up that thing goes to 330+ ampere for about 10 to 15 minutes after starting to ramp back down as the pack voltage climbs to 420 to 425 volts. The superchargers can sustain 120 kilowatt without problems.

author: richard.cs
author_rank: Super Contributor
timestamp: October 26, 2018, 08:47:07 am
content: In an attempt to answer these I have acquired a copy of BS EN 61851 but I've not read through it yet. I'm hoping at least some will be in there. I am aware a lot of things are down to what the car manufacturer chooses, but I'm hoping that there will be at least some "compliant charging points will do X, compliant cars will charge from Y and not be damaged by Z" stuff in there. I'm interested in what happens in the corner cases, e.g. the question as to whether the cars (are required to) monitor the neutral current or otherwise prevent sillyness if you give them 3 connections to the same phase.

author: boffin
author_rank: Unknown
timestamp: October 28, 2018, 09:39:04 pm
content: Quote from: richard.cs on October 22, 2018, 09:39:54 amMy EV has a J1772 socket, which supports one phase L/N or L1/L2. Signalling is done from the EVSE to the car to say what the maximum current that can be pulled by way of a square wave suty cycle. There's a lot of detail on the Wikipedia page for the J1772https://en.wikipedia.org/wiki/SAE_J1772