MG4 EV - Switching to 15amp Cable Worth It?

nomisg on 04/07/2024 - 14:48

We have had the mg4EV for about 6 month now and have been charging at home when the sun is out with the supplied granny/trickle charger from MG.

I have around 25kw of roof top solar and based in Adelaide. Car largely sits as home 5 days week, as we work from home most the time.

Charging is very slow and and looking at my cable its rated current is 8amp. Its doing its job mostly, but sometimes we need to give it boost oversight. Its run about car (school drop off, grocery runs etc) and we a deisel SUV for longer trips.

I do have a 15Amp socket I could use and can see 15amp, type 2 chargers in the $150-250 range. Would I be correct in assuming that I would almost double my charge speed with this set-up?

If so any recomentation on a 15amp charger, good brand/features?

I could go down the dedciated wall charger, I'm on 3 phase, but seams a bit over kill for my use case and would be costly. And also concerned on cloudy days, they might end drawing power from the grid which will be even more costly.

Cheers

Automotive Electric Vehicle MG

Comments

  • pegaxs on 04/07/2024 - 14:58
    +3

    25kW for a home solar array? Or are you on a residential block or an industrial shed or something? Or do you mean it produces 25kW over a whole day of sunshine? 25kW just seems like a MASSIVE system for a house (it's up around 50 to 70 panels on your roof??).

    Anyway, yeah, sure, go up to 15a. It cant hurt if you have a 25kW system. 15a would only pull about 3kW at most (losses and all that) so you still have 22kW to play with?

    Would it double your charge speed, no. it would improve by about 1/3rd. On a 10a socket with a 10a charger, you go from about 2400w to 3600w for a 15a charger. If you have the 51kWh battery, a 2400w charger would take about 22 hours to charge from flat. 3600w would take about 15 hours, or only a reduction of about 7 hours, while still significant, still not "half". Compared to your 8a charger, a 15a charger would be significantly faster, 27 hours for 8a vs 15 hours for 15a. (Please note, this does NOT allow for electrical losses and individual experiences with voltage and chargers are going to be different.)

    Best option would be to go with a dedicated wall box that is solar aware and let it work itself out. It will work out your energy usage and your generation and only skim off that up to the generation cap. Most home wall boxes are 32a, so that would be twice as fast as a 15a charger… But… then again, "cost". A 15a granny brick will get you in the pocket for about $200~ish, a dedicated wall box will set you back about $800 + install costs to run a 32a breaker and wiring.

    Only buy a 3 phase unit if you either want to "future proof" your installation or your vehicle supports it. I have a 3phase charger on my house, but my car only supports single phase. I bought it because I have friends who come over and their cars support 3 phase and my next car will probabvly support it… but honetly, unless you are doing 200+ km a day, every day, you dont really need a 3 phase charger, even if your car supports it.

  • JimmyF on 04/07/2024 - 15:04
    +1

    Would I be correct in assuming that I would almost double my charge speed with this set-up?

    Its not double, 10a to 15a is a 50% increase. Generally you have to run at 80% load rating, hence why your 10a charger is running at 8a. Some chargers let you go all the way to 10a or 15a.

    I could go down the dedciated wall charger, I'm on 3 phase, but seams a bit over kill for my use case and would be costly.

    Which MG do you have? As only the long range will support 3 phase chargers.

    https://evse.com.au/ev-car-guide/mg/mg4

    And also concerned on cloudy days, they might end drawing power from the grid which will be even more costly.

    What brand is your solar? Some have EV chargers that allow solar charging etc. If now, get a zappi charger installed. It has a charge on solar only option, so will adjust up and down to match the solar output.

  • nomisg on 04/07/2024 - 15:13

    Yeah its a massive system, solar panels on the main house, and on the detached studio and detached shed. Had it installed in the good old days (5 or so years ago) and it paid itself off fairly quickly when we had a good FIT. Its crazy now, I exported more to the grid then I took of it and still ended up with $1000 bill.

    I don't really have 22kW to play with, say on a cloudy/rainy day and we make a point of doing the washing, dishwaher, clothes drier during the day and also 3 aircon's are running most of the time. Have seen a bad cloudy/rain day, Total yield was only 7.77 kWh

    I'll have a look into these solar aware options. But something like this does seam like a short term upgrade and would be handy on shorter overnight road trips
    https://www.ebay.com.au/itm/314873971220?mkcid=16&mkevt=1&mk…

    • pegaxs on 04/07/2024 - 15:55

      I think that reply was for me… And panels on house, shed and studio would make sense then. 25kW is still overkill for a house. I'm surprised that they would even let you plug that into the grid. It would be about 35a per phase… Might be different in SA, but I thought it was only up to 5~6kW, or 20~25a per phase? Meh…

      That charger you have would not be a good charger, or, it would be good, but it is non-compliant with a 15a to 10a tail on it like that. There is nothing stopping you plugging in that charger at 15a rate into a 10a socket with that setup. What you would need is a 15a RCBO, something like this or this as the go between, not just a plug tail. I am not sure how that unit tells what tail is plugged into it, but there is no way that 15a to 10a fly lead is even remotely legal.

      But sure, that would work ok on a overnight trip, providing you had access to a 15a outlet, or you could turn it down to 10a and use it with the RCBO (not that stupid 10~15a adaptor tail)

      • nomisg on 04/07/2024 - 16:16

        Ok I just double checked, its actually 22kw of solar panels and inverters are 4 x 5kw, so max is actually 20kw. I recall my installer going over with the panels, as they never run at 100% anyway and do degrade over time. Oh well, as you said, Meh :-)

        Thanks for the safety advise, question though, the cable does have adjustable amp setting e.g. 6-15Amps. If I make sure it is set to under 10amp is it still a safety issue? I wonder if the cable limits itself by default.

        • nomisg on 04/07/2024 - 16:44

          Amazon listing for the same product says "Power up your electric vehicle anywhere you have access to an AU 15A socket. For AU 10A sockets, just use a 10A to 15A adapter (ensure charger current is set below 10A). With a 6-meter total length, reaching your parking spot is a breeze. Enjoy the convenience of hassle-free charging, no installation required."

          But i suppose, just because they this, doesn't make it legal?

        • pegaxs on 04/07/2024 - 17:09

          If I make sure it is set to under 10amp is it still a safety issue?

          And for that one time that you dont, or you forget or it gets bumped or knocked or someone who doesn't know what they are doing touches it…

          Just get the right adaptor for it. You cant go from 15a down to 10a using just a straight through tail. At best it will pop a fuse/trip the breaker, worst case, it will cook the wiring in your house and/or cause a fire.

          I wonder if the cable limits itself by default.

          Some cables do, but they dont have a standard 15a plug on the end. I am 100% ceretain that the unit you posted would NOT have tyhis feature to "auto-detect" what plug was on the lead. I would not use it on 10a sockets without the RCBO adaptor I mentioned above. $59 for the adaptor is a lot cheaper than replacing wiring in your house.

      • JimmyF on 04/07/2024 - 16:59
        +1

        25kW is still overkill for a house. I'm surprised that they would even let you plug that into the grid

        The regs today allow for 10kw of solar panels per phase with a 5kw export limit per phase. So on 3 phase you can have a 30kw system with 15kw export (rest can be used under self consumption.)

        Depending on when it was installed, the export could have been higher.

    • JimmyF on 04/07/2024 - 17:05

      But something like this does seam like a short term upgrade

      That isn't 'legal' for use in Australia, you can't use a 10a to 15a cable like that, as there is nothing stopping you drawing 15a from a 10a socket.

      Correct ones have a 'tail' that is replaced, you remove the 10a plug and put in a 15a plug.

  • nomisg on 04/07/2024 - 15:23

    Which MG do you have? base model mg4ev so only upto 7kw charging
    What brand is your solar? SMA Sunny boy 5kw inverters, multiple of them

  • nomisg on 04/07/2024 - 15:25

    p.s. my current charger is only 8amp, not 10amp

  • wannagrababargain on 06/07/2024 - 20:15

    After investing so much into solar you would be nuts not to get a 3 phase 22kw smart charger. Even if the car only supports 11kw. It will harvest the pv surplus and throttle itself back if your aircon etc is on. Best way to make savings is self consuming before FIT. Having a big fat EV battery is one of the best ways to soak up the spare generation when the sun is shining and your system is cranking.

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