3 phase 16A charger to MG4

[Chris698]

Hi.

I collected my MG4 last week and I'm just trying to get my head around the inner workings of the chargers etc.

My work has a 3 phase 16amp charger and obviously the MG4 is single phase charging.

My cable is a 32A single phase type 2.

Am I right in assuming the maximum charge speed I'll get with this set up is 3.6ish kW? (The 16A through the one phase).

If so is there any cables on the market that act as a three phase to a single phase so I can get more power down the one phase of the mg4 for faster charging?

Sorry if this makes zero sense I'm still figuring it out.

Thank you.

 

[tsedge]

Hi.

I collected my MG4 last week and I'm just trying to get my head around the inner workings of the chargers etc.

My work has a 3 phase 16amp charger and obviously the MG4 is single phase charging.

My cable is a 32A single phase type 2.

Am I right in assuming the maximum charge speed I'll get with this set up is 3.6ish kw/h? (The 16A through the one phase).

Yes, you'll get 3.6kW, or a bit less after losses.

If so is there any cables on the market that act as a three phase to a single phase so I can get more power down the one phase of the mg4 for faster charging?

Not to get a 3-phase 16A charger to combine phases into a single one - the phases are different so you can't splice them together.

If you had a 32A 3-phase cable and 32A 3-phase charger you'd get the full 7kW.

Sorry if this makes zero sense I'm still figuring it out.

Thank you.

It makes sense.

 

[yodu45]

Hi, I have a 400V 3 phase 16A per phase, I go up to 11kW (10.5 exactly) at my house.

 

[tsedge]

Hi, I have a 400v 3 phase 16A per phase, I go up to 11kw (10.5 exactly) at my house.

Only some MG4s have a 3-phase 11kW onboard charger, most have single phase 7kW.

 

[Chris698]

My MG4 is definitely only a single phase on board charger so I'm guessing no matter what I do I'll only get 3.6ish kW if the charger is 16amp. I found a charger that's called "three phase to single phase" but guessing it won't do what I'm wanting it too.

 

[siteguru]

EU models may well be different.

 

[tsedge]

EU models may well be different.

True, I don't see people's location when using my mobile (99% of the time that's what I am using).

 

[Rolfe]

Turn your phone round to get landscape view and you'll see the location.

 

[Grriff]

MG4 Trophy - a Guide may be of help (chapter 9).

 

[Ayoull]

Only some MG4s have a 3-phase 11kW onboard charger, most have single phase 7kW.

Single Phase 6.6kW not 7kW unfortunately, as over a few hrs the 400w makes a difference.

 

[tsedge]

Single Phase 6.6kW not 7kW unfortunately, as over a few hrs the 400w makes a difference.

I'm just rounding. ?

 

[Ian Key]

I'm just rounding. ?

I've been rounding for years and Christmas improved?? the situation ?

 

[fnegroni]

Sorry to revive a dead corpse, I mean thread.

But I’ve recently been playing around with charging at 3.7kW and 7.4kW.

My observations so far indicate tha to charging my car at 16A is a fair bit more efficient that at 32A
Whereby I get 6.5kW from a 7.4kW EVSE, with 7.4kW supplied but only 6.5kW going into the battery, nearly 1kWh lost for every hour of charging.
While I get 3.4 kW if I set the on board charger to 16A and the supply in one hour shows 3.7kWh , so a loss of 300W which is quite a lot better.
Has anyone else observed same?

 

[Coulomb]

7.4kW supplied but only 6.5kW going into the battery, nearly 1kWh lost for every hour of charging.

1 kW of losses is hard to believe. That's enough power for a small toaster.

I think it's more likely that the "7.4 kW supplied" is simply a guess or a rating based on 230 V and 32 A (230 x 32 = 7360), i.e. the maximum possible power, not the actual power delivered. Many MG on-board chargers are rated at 6.6 kW (I assume that's output), so that's why you see around 6.5 kW going into the battery. The other 0.1 kW (100 W) will probably be going into the DC-DC, to supply various 12 V loads, such as computers and cooling pumps.

So with 32 A available, there is a large 3.3 A "gap" between what the EVSE can supply, and what the on-board charger will draw.

With 16 A available, this gap disappears; the on-board charger can take every bit of the 16 A that is available. So now the power drawn by the on-board charger can be very close to what the EVSE can supply. There will be very roughly 5% loss in the AC to DC conversion process (about 180 W), and again some 100 W for the DC-DC. So that comes to 280 W. There is also a lack of precision and accuracy.

In any system like this, there are usually fixed losses (e.g. to power the electronics, fans, switching losses), and variable losses. The variable losses are typically resistive, and so are proportional to the square of the current (P = I²R). So at low power, the fixed losses will dominate; at high power, the variable losses will dominate. Somewhere in between will be the most efficient, but I don't think it's worth worrying about that level of efficiency.

 

[fnegroni]

1 kW of losses is hard to believe. That's enough power for a small toaster.

I think it's more likely that the "7.4 kW supplied" is simply a guess

I just looked at my receipt from the last charging session at a genie point on AC. An 11kW (or is it 22kW?) charger.
Guess what, although my car was only taking around 6.5kW, they billed me as if they were supplying at 10kW.

I’m going to question the transaction now as it seems they billed me for way more.

I’m going to do a test at work later this evening. It reports how much was supplied and I can time it to check.

I just looked at my receipt from the last charging session at a genie point on AC. An 11kW charger.
Guess what, although my car was only taking around 6.5kW, they billed me as if they were supplying at 10kW.

I’m going to question the transaction now as it seems they billed me for way more.

I’m going to do a test at work later this evening. It reports how much was supplied and I can time it to check.

I just watch the video I took because something wasn’t right.
Either genie point point scammed me, or something is seriously wrong with the onboard charger.
When I switched the on board charger to 16A, the supply at the genie point screen showed this:

Meanwhile my car showed this:

I am now writing a complaint to Electroverse for the transaction, and will email genie point to ask what the heck is going on.

 

[shpub]

This looks like another issue. What isn't right is 400v for an AC charge? Normally on an AC charge the voltage is not quoted as it is basically 240v mains, even with a three phase connection. Three phase is normally 415v anyway. That data looks like a DC charge. It is as if the Genie was doing a DC charge before and didn't clear its display data.

I did have a sort of similar situation with a destination charger where a Tesla had plugged in on the other bay. I plugged in on the other and the started charging only for the Tesla to start. The Tesla had either left the plug in place with no charging or had finished charging. The EVSE saw it was in the first socket and promptly started charging that car and displayed that data on my bay screen. I had to phone the operator to reset the unit after removing the Tesla plug and then it worked fine. Never had that happen again and it was nearly 8 years ago.

The car readout looks fine.

I would try it on a different charger as it does look like Genie is misbehaving in some way. Not a surprise as they are not rated as a very good network. I have a 66% failure rate with them.

 

[fnegroni]

Unfortunately they charged me as if they were really supplying 400v x 28A for most of it (part of it was at 15A as I was testing it out): 6.6kWh in 40 minutes. Me thinks not ?
I sent them an email. I’m tempted to try it out again but I wonder how many other people have been over charged.

 

[Coulomb]

Single phase on-board chargers must be a nuisance for charger sites. No doubt they rotate the actual phases connected to L1 (all vehicles seem to charge on L1 if they only use one phase), but worst case they have a single phase vehicle charged into every third dispenser, or whatever pattern the charge site uses, meaning that they all end up on one phase. The site might have to throttle the output so as not to overload one phase of the transformer, utilising only one third of its potential. In practice this would rarely happen, but it could.

I wonder if Genie will try to argue that you're drawing 15 A from one phase, when they went to the expense of providing all three phases, so if you're wasting two phases that's your fault!? ?

Edit: It does seem to be the case that authorities are forced to be very accurate and fair charging only for actual power used. So I doubt that Genie could get away with this.

BTW, 6.0 kW from 400 V and 15 A looks as though the coder for the Genie charger didn't understand three-phase power at all. The current will get split with a delta load, and the voltage gets split if it was a Y/star load. That's why 3-phase power is always V * I * √3, never V * I (where V here is the line-to-line voltage, standard for 3-phase calculations).

they charged me as if they were really supplying 400v x 28A for most of it

No, 400 * 28 * √3 ≅ 19.4 kW, time 39/60 hours = 12.6 kWh. Of course, that's if they computed three phase power properly, and they have not.

They actually charged you 6.6 kWh for 40 minutes, or an average of 6.6 / (39/60) = 10.2 kW, or 44 A at 230 V. In other words, they charged you for all three phases, or 200% overcharged. (Charged in this case in the sense of money, not energy into your car's battery).

But yes, it amounts to much the same thing.

 

[shpub]

I wonder if Genie will try to argue that you're drawing 15 A from one phase, when they went to the expense of providing all three phases, so if you're wasting two phases that's your fault!? ?

They might but that is not how they should work. To meet the standards the EVSE has a current sensor on each phase and that provides independent current values which they can add up to create the total. You can't have a single overall value as you don't know which phase is being naughty. I have plugged in where 2 of the three phases were used and it didn't matter what which two they worked fine.

That looked like it was assuming you were doing a DC DC charge. Which connector did you use? If it was the combo with the two additional DC sockets I am wondering if that fooled the Genie into thinking it was a DC charge when it wasn't. IIRC the AC side may still work correctly.

So you plug in with the combo but select AC or vice versa. Genie gives you AC charging because that is the correct car signaling but thinks wrongly that this is a DC charge from a payment point of view be cause the signaling is going through the DC channel. The CCS standard uses the Type2 AC signaling to start the powerline stuff. Hence the display and the descrepancy. This is a blue sky thought but it does fit the symptoms.

 

[fnegroni]

Which connector did you use? If it was the combo with the two additional DC sockets I am wondering if that fooled the Genie into thinking it was a DC charge when it wasn't. IIRC the AC side may still work correctly.

So you plug in with the combo but select AC or vice versa. Genie gives you AC charging because that is the correct car signaling but thinks wrongly that this is a DC charge from a payment point of view be cause the signaling is going through the DC channel. The CCS standard uses the Type2 AC signaling to start the powerline stuff. Hence the display and the descrepancy. This is a blue sky thought but it does fit the symptoms.

I was plugged in the type 2 port with my own single phase 32A cable.
No other car was plugged in at that time.
I have the video where I look at the charger, show the cable being plugged in and the screen in the car, just in case ?