Charging regime advice

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meow
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#3245250 6-Jun-2024 13:32

If you've got a standard 10a double plug you may be able to retrofit this with a 15a socket assuming your charger supports that. May be a cheaper solution.

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jonathan18

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#3245526 7-Jun-2024 05:58

michaelmurfy:
If you've got a standard 10a double plug you may be able to retrofit this with a 15a socket assuming your charger supports that. May be a cheaper solution.

Yep, this is what I mentioned as an option earlier in this thread. But, other than the Tesla UMC, do many other chargers come with or are easily adapted to use a 15A tail?

PSLog

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#3245536 7-Jun-2024 07:50

jonathan18:
michaelmurfy:
If you've got a standard 10a double plug you may be able to retrofit this with a 15a socket assuming your charger supports that. May be a cheaper solution.

Yep, this is what I mentioned as an option earlier in this thread. But, other than the Tesla UMC, do many other chargers come with or are easily adapted to use a 15A tail?

It was a single socket.
I've bought a 20A socket and a 20A plug to fit.
I'll be ordering a Type 2 16A charging cable today (I'm willing to take the risk of an Aliexpress one).
Was planning on replacing the plug supplied with this cable with my 20A plug.

Regarding the mention of a "15A tail", am I missing something with my plan, above?

PS. I'll also be rutting a 20A RCBO on this circuit at the switchboard

jonathan18

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#3245542 7-Jun-2024 08:12

In regards to the Tesla option I'm talking about - the mobile EVSE that used to be supplied with new Teslas but is now a charged extra comes with two 'tail' plugs - a standard 10A 3-pin plug and a 15A one with the longer pin as per... (ack this photo isn't AU/NZ plug but it's from their NZ site!)

One can also buy a caravan tail that fits into the same EVSE (I've got this as well, making it a pretty flexible unit).

Some have found it's a more cost-effective option to replace a standard 10A wall socket with a 15A one (assuming they've also checked the wiring and circuit breaker etc!) and use the 15A tail than install a permanent fast charger.

PSLog

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#3245543 7-Jun-2024 08:18

jonathan18:
Some have found it's a more cost-effective option to replace a standard 10A wall socket with a 15A one (assuming they've also checked the wiring and circuit breaker etc!) and use the 15A tail than install a permanent fast charger.

Yep, that's essentially what I'm doing.
I'll still have the 8A cable supplied with the car for "away" charges.

jonathan18

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#3245553 7-Jun-2024 08:54

Out of interest, @PSLog, any chance you could share a link to the EVSE you've bought from AE?

We've found the Tesla EVSE is the more useful one to take with us when travelling, given that flexibility (not that I've ever used the 15A tail, but the caravan one we use a decent amount). TBH, we've never once used the EVSE that came with my wife's MG4.

trig42

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#3245572 7-Jun-2024 09:38

I've used the EVSE that came with mine once. We were away at a Bookabach in Greytown.

It took all afternoon and all night to go from about 40% to about 80%.

That Tesla one looks pretty good, different tails means you can use it at caravan parks - 16A is about 5% SOC per hour - not too shabby.

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jonathan18

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#3245584 7-Jun-2024 10:43

trig42:

I've used the EVSE that came with mine once. We were away at a Bookabach in Greytown.

It took all afternoon and all night to go from about 40% to about 80%.

... and yet for many people charging at 8A is all they need! It really is a matter of horses for courses...

In your case, while it may have taken ages to charge that 40 percentage points, that could be the difference between needing to charge at a commercial charger or not (and the Wairarapa isn't exactly inundated with good chargers, though it's getting better).

I was surprised at how handy even using the granny charger at 8A was when we travelled around the SI; similarly, we charged at a number of Air BnBs (and paid them for the power used) - doing this significantly reduced our need for fast charging. We also found sticking a plug out the window and charging the car when it's not being used at night was far less disruptive than other locations where we couldn't do this, where we would have to make special trips to charge (frustrating when the options are poor - Dunedin being case in point).

PSLog

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#3245586 7-Jun-2024 10:47

This is the one I have just ordered.
https://www.aliexpress.com/item/1005003651941213.html?spm=a2g0o.order_detail.order_detail_item.3.29edf19cpVQkkK

They have sold a lot; they have reasonably good feedback; it has a 3.5m lead, which is all I need.

PSLog

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#3255426 2-Jul-2024 01:07

Have used the above-mentioned charging cable a couple of times now.

Not too sure about it.

When set at 16A, I have found that the car reports a charge rate cycling between 0.3kW to 2.6kW (and anything in between).
Which doesn't seem right.

I note that the voltage displayed in the cable box drops from 240V, with no load, to 228V when the car is charging.
Is this what I should expect?

I have not yet found where you can read the exact kWh in the car's battery on the MG4 so it is a bit hard to figure out how many kWh the charger is achieving over a given period. Using the blunt instrument of change in SOC % - from the one measured charge I've done - it appears to be adding about 3.2kW per hour. Not sure how it does that, when the maximum instantaneous charge rate displayed is 2.6kW ???

Any thoughts on the above?

Tomorrow, I'll try the MG 8A charger and see if the kW figure still cycles. I'll report back.

PSLog

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#3255481 2-Jul-2024 13:01

OK. I tried the MG branded 8A charging cable, and the charge display in the car behaved the same way: displaying 0.0, 0.3, 0.7, 1.1kW in a cycle.
So, maybe the Aliexpress one IS OK.
The measured charge last night appeared to add 3.2kW per hour, so it might be that the charging display in the MG is a bit quirky.

Mehrts

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#3255630 2-Jul-2024 17:08

PSLog:

I note that the voltage displayed in the cable box drops from 240V, with no load, to 228V when the car is charging.
Is this what I should expect?

This is normal. As current increases, voltage will decrease. The amount of voltage drop is determined by the cable conductor size (the thicker, the better), and the termination tightness & quality along the run.

This applies to all runs of cable, from your switchboard to the EVSE itself. Speaking of which, what mains plug end did you select? I ask because none of those are the Aus/NZ standard ones. The one that looks similar but it upside down is for the Chinese market.

RunningMan

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#3255643 2-Jul-2024 18:49

PSLog:
The measured charge last night appeared to add 3.2kW per hour,

You might just be getting confused with units - there's no such thing as adding 3.2kW in an hour. You can add 3.2kWh in an hour (i.e. charging at 3.2kW for. 1 hour). Bear in mind there will be charging losses of say 5-10% (charger inefficency, heat etc.) so charging at 3.2kW for an hour might only add 3kWh to the battery.

PSLog

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#3255648 2-Jul-2024 19:25

RunningMan:
PSLog:
The measured charge last night appeared to add 3.2kW per hour,

You might just be getting confused with units - there's no such thing as adding 3.2kW in an hour. You can add 3.2kWh in an hour (i.e. charging at 3.2kW for. 1 hour). Bear in mind there will be charging losses of say 5-10% (charger inefficency, heat etc.) so charging at 3.2kW for an hour might only add 3kWh to the battery.

Yeah. I vaguely wondered about that as I was posting it :-/

The 3.2kWh that I posted was the difference between the start and finish SOC (multiplied by the stated battery capacity) - so I guess is actual charge. Thanks for pointing out the efficiency loss.

tim0001

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#3255649 2-Jul-2024 19:29

Not sure if you've already seen this, but there's a detailed explanation of the impact of shallow charges in this video in the "Engineering Explained" youtube channel.

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