question

sheidler avatar image
sheidler asked

Disable slave charger in parallel environment

Hello everybody


My Setup is as following:

5 Pylontech US3000C Batteries

1 Multiplus-II 48/5000/70 GX (GC disabled by unplugging power to GC-board)

1 Multiplus-II 48/5000/70

1 Cerbo GX

And a few other thing which are not important for my question


The setup should get placed into my RV. So grid power is sometime only secured by an 8A breaker. In single mode I can limit max AMP to 6.5A. But in parallel mode the lowest would be 12.2A which would kill grid power if more than 8A would be needed for charging.

What if I only connect the master to grid power and do not connect the slave to grid and disable the charging function of the slave.

Is this possible - well should be - but can I modify the input current limit afterwards.

I do need parallel mode as I want to use power from batteries/solar for my power consumption which could be more than 8kW - for example induction cooking and air condition...


Thanks for a few hints....


Kind regards



Stefan

Multiplus-IIMultiPlus Quattro Inverter Chargermultiplus in parallel
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6 Answers
klim8skeptic avatar image
klim8skeptic answered ·

You might be able to run 2 multiplus in series?

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sheidler avatar image
sheidler answered ·

Thanks for the hint - looks like an solution....

Programming/Cabling such solution is possible. But could both Inverters be connected to the same output phase?

They are not synchronized like in parallel mode.



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shaneyake avatar image
shaneyake answered ·

Have you updated the firmware on your inverters?
It looks like I can set mine to 1A per inverter. Can you maybe post some screenshots of where you are seeing this limit?

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sheidler avatar image
sheidler answered ·

Well there is no need for an screenshot as it is described in the manual that for the 48/5000/70 the minimum limit is 6A and this is doubled in parallel mode...


The setup to serial sounds interesting but of course there is no given wiring example. I did check the video given by klim8skeptic. But there is no further explanation.

And he is not using grid power. So at the end I do have no clue.

And yes all firmware of all of my devices are up to date.

But thanks anyway

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shaneyake avatar image shaneyake commented ·

No where here does it actually say it will double when in parallel.
I know the hardware under ESS mode is able to reduce the current to 0.045A
https://www.victronenergy.com/media/pg/MultiPlus-II_230V/en/configuration.html
screen-shot-2022-03-24-at-73958-pm.png

It does state under
https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems

"Setting an input current limit works differently when setting it on a remote control panel, for example a DMC or GX device. Then (a) only one value can be set by the user, not a different for each phase, and (b) the configured limit will be used as the total limit for each phase. Example, setting 30A in a three phase system of six units (two per phase), on a DMC or GX Device, results in a max input current limit of 30A per phase. The difference of both methods is due to the different use case of both ways of setting it: settings in VEConfigure are supposed to be fixed in the install and done be the installer, for example matching an installed generator. And the input current limit as set on the GX device is intended to be set by the end-user, for example on a yacht or in a motor home, and being able to set it depending on the actual shore connection - and ofcourse without having to do the maths of multiplying with the number of installed units on a phase.)"

So it would seem that you could set the limit on the GX and it should work down to 6A.
Have you tried it?

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sheidler avatar image
sheidler answered ·

What about AC coupling. One Multiplus connected to grid power and both connected as Inverter to battery. The Multiplus not connected via VE.Bus to each other.

Ok the second one is not an PV Inverter System. But in principle should work as well. Both AC-OUT-1 from the Multiplus to an single phase breaker bus.

To make it a little bit clear attached an overviewpage-1.png


page-1.png (363.8 KiB)
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shaneyake avatar image shaneyake commented ·
You can not connect the AC-OUT of 2 inverters without the VE.Bus cable and parallel config.

You can AC-Couple the 2 but this is not supported by Victron at all. You will need to wire Shore to Masters AC-IN and then Master AC-OUT to Slave AC-IN and then AC-OUT to Loads.
You could use ESS to set a grid setpoint at 1500W and just have both inverters in normal parallel.

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Herve RV Nizard avatar image Herve RV Nizard shaneyake commented ·
That s interesting. I had a similar situation I wanted to solve. So what you are saying is that Multi 2 becomes the main and supplies alone loads < 1500w. then "calls" ac in at 1500 ( from Multi 1) so both can supply up to 4 to 5 kva each .

but how would M2 REACT when having to supply close to 10 Kva alone ( in terms of AC Output)?

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sheidler avatar image
sheidler answered ·

updated overview

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