Multiplus-II not schedule charging with ESS

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bhan asked Mar 21, '23

Multiplus-II not schedule charging with ESS

Hi
I have set a scheduled charge time from 00:30 for 4 hours (cheap rate from grid), but the charger doesnt relaibly start
I have the ESS assistant, latest FW on all devices with Multiplus-II 24/3000 on FW v502

I also have my electric car set to charge during this 4 hour window, i do not want the Inverter of the Multiplus-II to be on during this time period, i can pull all the power from the grid at this time and fully charge the battery

Looking at VRM, i can see the car starts charging at 0030, but as you can see the Multiplus-II doesnt, then around 02:47 the Multiplus-II does start to charge

As you can see, for some reason the Inverter pulls 115amps from the battery for 20 minutes around 00:42, why?, i had also set the max inverter output to 250W, so why is the inverter pulling 110amps?

Any advice would be greatly appreciated, ive spent hours trying varouns things, i can never get this to work as i ecpedted.

As a test i setup a second scheduled charge time, once again this started but the battery didnt not start charing, while still in this charge period, i changed "Minimum SoC (unless grid lost)" to 90% and chraging immediatly started, why?

Thanks

Brett

battery charging

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Jason - UK answered · Mar 21, 2023 at 10:05 AM

@bhan the 3kva unit is limited to 32amp though the unit. Do you have your car charger on the AC out side of the Multiplus as if so, you're maxing out your power though the unit with just the car charger therefore the Multiplus wont charge until the car charger has finished or has started to reduce the amount of amps its pulling.

If the car charges is on the AC in side of the Multiplus, im assuming you'll have a AC sensor on your incoming mails supply? If this is your arrangement, I assume you have power assist set up?

Do you have a schematic of you system?

I cant run all my loads though my Multiplus as in Winter, I often hit the 50amp limit on my 5kva unit. Because of this, I have the EV charger on the AC in side of the Multiplus as not to overload the unit.

Schematic in the photos on the below link.

https://vrm.victronenergy.com/installation/171934/share/db6807bb

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Jason - UK commented · Mar 21, 2023 at 10:20 AM

@bhan the 2kva unit is limited to 32amps which is about 7kW which is what your car charger is pulling

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bhan answered · Mar 21, 2023 at 10:42 AM

Hi

Ahh sorry, i didnt include that info!,

I have a grid tie setup, AC-IN into the Mulitplus-II 24/3000 on a spur from my consumer unit, with the current clamp into the Multiplus-II (two wire), current clamp is around the main supply into the house, so includes all power coming into the house. almost nothing is connected to the critical load AC-1-OUT output, a couple of lights only. I also have some DC loads directly off the 24v battery for Internet Router, Wifi and a Network storage NAS. And AC-2-OUT isnt connected to anything

Hope this helps a little to understand my setup?

Am i correct in thinking that while i am in an active charge schedule that the Multiplus-II will not try and push any power to my grid tie?, even though the load being reported via the current clamp is reporting im using upwards of 10KW?

Thanks again

Brett

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Jason - UK commented · Mar 21, 2023 at 11:26 AM

@bhan Correct, when you have an active charge cycle, any other power you consume will be from the grid, even if your batteries are at the set point, your charger will idle.

With regards to your original question, when you set up the Multiplus in VE Configure, what do you have the AC input limited to? If set to 32A, it will limited the energy passing the CT sensor on your incoming tails to 32Amps.

You have got me thinking now that if you set the limit to 32A but you are pulling more than 32A, would the inverter kick in to maintain 32A limit from the grid?

PS, its helpful if you @someone so they know you have replied. ;-)

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bhan Jason - UK commented · Mar 21, 2023 at 11:39 AM

Ahhh!, i had thought that the current clamp measures the current coming into the whole home as a grid meter, but perhaps it only wants to see what is actually coming into the Multiplus-II, now you have me thinking, it would certainly fit with what im seeing

Im going to remove the current clamp and add an external grid meter and see if that changes things, give me a few days !

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Jason - UK bhan commented · Mar 21, 2023 at 12:37 PM

@bhan It sounds like to me you just need to have your CT sensor AFTER your EV charger but before the AC loads so the Multiplus is only concerned with the house and that way the EV charger can operate independent of the Multiplus / house AC loads.

I have actually removed my CT sensor as it doesn't serve a purpose as I have my whole house on my AC out on the Multiplus therefore i just use the AC sensor built into the Multiplus, which allows the EV charger to operate independent. The EV charger has its own CT sensor which is in place of the Victron one shown on the below which looks for PV export so when I cam exporting energy, the EV charger matches the charging to the export.

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Modifications Space

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Answer 1 · 2023-03-23T09:28:20Z

bhan answered · Mar 23, 2023 at 09:28 AM

Fixed, as we thought, i had made two errors

The current clamp probe connected directly (2-wires) to the Multiplus is not a grid meter and should not be placed at the incvoming power into the home

I removed that current clamp and replaced with a full grid meter, now everything is as expected, car and battery charges during the 4 hour cheap electricty window

Thanks for your help, it certainly drove me to the issue and a fix

Thanks

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Jason - UK commented · Mar 23, 2023 at 09:36 AM

@bhan Good to hear its all sorted. Enjoy the energy savings. Im 12 months in with my Multiplus II 5kva units and the energy Im saving is massive.

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