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gjones84 avatar image
gjones84 asked

Multiplus Max Export Limit Not working

Good Afternoon,


Im am wondering if someone could maybe point me the right direction of why the max inverter output function does not work correctly with my system.

I have a multiplus 2 running on 18650 cells in a 15S40P configuration with a batrium watchmon 4 as my bms. I am currently running mode 2 ESS on the victron. Everything so far is working great. However the 'max inverter power limit' doesnt work. See below the overview of what I am running.


Ive tried adjusting this to different values in Venus OS but still no change in the behaviour. This is the setting.


I am running Optimized without battery life. If i put the kettle on it looks like this below. Anything less than 3kw the load on the battery is always around 400-500W.



However if I then switch the oven on so the house load is 6kw the inverter runs at max output.



I've tried not running phase compensation but im at a loss why this setting doesn't work?? Really I only want to run my system at 1500W but if the house load is high it ignors the max inverter limit.


Any ideas what this could be?


Thanks


Gareth

ESS
ess-overview.jpg (34.8 KiB)
ccgx-maz-export-limit.jpg (62.2 KiB)
ccgx-high-load.jpg (57.6 KiB)
ccgx-high-high-load.jpg (56.5 KiB)
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Alexandra avatar image Alexandra ♦ commented ·

@gjones84

The max power affects how much the inverter tries to supply vs how much it passes through from the grid.

So if you have told it to supply only 2000w and you are using a 5000w load it will pull the other 3000w from the grid.

You could try remove circuits from the output of the multi that you do not want the multi powering.

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gjones84 avatar image gjones84 Alexandra ♦ commented ·

Hi Thanks for your reply.

I suppose this is where I want better control of my system.

The multiplus in mode 1/2 seems to do what ever it likes. This is a snap shot from a few minutes ago. House load was 5065w, solar 1668w and battery was discharging @ 773w. I think there are so many variables. Like the grid frequency and the amount of solar.

Do you think mode 3 would be a better option? I have all the values are there in mymodbustcp controller. I take I could tell the multiplus what to discharge dependant on houseload?

Thanks


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Alexandra avatar image Alexandra ♦ gjones84 commented ·

You have basically already done that through the was setup. 1) 5% in case of grid failure sets how much it is allowed to discharge. 2) Optimized without battery life alters that as well the multi won't be charging it up to 100% An excerpt of the ess manual mode 3... When using Mode 3 with a managed battery, please note that the maximum discharge current sent by the battery will be ignored. The implemented control loop should take care of discharge limits communicated by the battery.

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman commented ·

Please share more information about:


“ 18650 cells in a 15S40P configuration with a batrium watchmon 4 as my bms”

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gjones84 avatar image gjones84 Warwick Bruce Chapman commented ·

I wanted to purchase the offical Victron Lithion ion batteries but there were just too expensive for my ESS build. I sourced 600 new LG DAS18650 cells and assembled them into 15 x 40 pallets. They are around 2.2Ah each so each pack is around 90AH. Each pack is connected in series x 15. The battery works out to be a 4.8kwh.

Like all lithium ion cells they will require continuous monitoring so I used a Batrium Watchmon 4 BMS that monitors each cell pack voltage, temperature and the shunt current. This is connected via canbust to a CCGX (or in my case a Rpi4 with a canhat). That is then connected via VE.Bus to the Multiplus 2.

See below some links of materials used in my custom build :)

https://www.batrium.com/

https://secondlifestorage.com/showthread.php?tid=1763

http://skpang.co.uk/catalog/pican3-canbus-board-for-raspberry-pi-4-with-3a-smps-rtc-p-1572.html


cheers


Gareth

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Warwick Bruce Chapman avatar image Warwick Bruce Chapman gjones84 commented ·

Beaut! In the end was it more cost effective than Victron?

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