question

Hi, the main "issue" I found so far running a system on extended CT is that the inrush current is absorbed by the battery and inverter whilst the grid set point is ramped up internally to match a set max inverter output, even on a multi with gx integrated.

On a energy meter run system the inrush is absorbed by the grid whilst the inverter is signaled to ramped up to max set/ permitted power.

This looks like being due to the CT comunicating directly with the inverter whereas the grid meter communicates via VE.

On large loads this can trigger overload warnings.

I understand the concerns about WiFi but one dedicated (433Mhz) for example can precent having to dig in 100 meter cabel....

Thanks for the information.

Is the Zigbee a reliable way to transmit to the GX? I would have 1 brick and 2 wooden walls in between the 2 point over a distance of around 15m

I am looking for a customer as well - according to community it works with the ET112... but I have no experience with this....

https://community.victronenergy.com/questions/135114/multiplus-ii-gx-zigbee-meter.html

Can anyone help, in the ESS manual it states if PV is on the input side of the MPII or any ac loads then a meter is required at the grid.

Does this mean that a meter is not required as long as the entire installation is on the output of the MPII?, that does not seem clear to me.

Yes that is right. If and only if your solar PV is on the AC Out side (you do not say) the Multi has no need for a grid meter as its internal sensor is sufficient. I have a system like this and ESS works fine.

I have added a meter for the PV for a different reason, ESS works OK without it but the Dashboard then shows only the difference between the AC loads and the solar input as there is no way for it to measure them separately. Also it does not register negative loads, so if the PV geneeration is more than the loads what you see is meaningless.

Hi Sharpener, my original plan was to have the PV on the Multiplus output and not use a grid meter, would this work as the AC loads in my house would be between the grid and Multiplus AC in? or do I misunderstand the manual?.

I can add a grid meter but it will not be straight forward.

My aim is to have excess PV for loads and battery charging during the day and power for loads on an evening.

If the house loads are on the AC In side you will definitely need some kind of meter between the grid and the house load connection point.

A external CT will be cheaper than a meter and give faster and better control of the grid setpoint. There are many posts on here about how to extend the CT cable if you need to, ranging from simple audio extension leads to wireless solutions.

AFAIR some people have been successful with a 20m extension using screened cable but if as you say it cannot be a physical cable (why?) I would guess that Zigbee might work. I have a barn conversion with 600mm stone walls, and wireless stuff (heating controls, alarms, DECT phones) all works with some limitations.

@Lifeingalicia has I think looked at this and may be able to suggest other ideas or links.

Clarification: If you feed in PV before any Multi (before ACIN) you need either an external CT or an energy meter to control total power.

The different handling of the Multi / GX see top of thread.

If you connect PV on ACout1 (critical) rule 1.0 aplies. Max PV max Inverter power.

If you connect PV on ACout2 it will switch off when power fails. Rule 1.0 does not apply BUT the max current/power running through a Multi depends on its type. E.G. 3000 = 3kW - but only short term nominal load 2.4kW...

For the latter two the inbuild CT can manage power.

If you need to be sure wireless works there is at present only the ET112 with the two zigbee converters. There are more potential sollutions but Victron does repect. can not support these.

If it is impossible to run a wire from a meter or CT and you only have two cables available a way to get round this is to have two PV feeds - one before ACIN and one within rule 1.0 on ACout1 (critical). Thus bat can power critical loads on failure and partial PV is used during this time. With SOC management "black start or dead lock" can be prevented.

The other PV switches off but then there are no power users either.

When it is running it will feed the Multi and any other users first then export. If bats are full excess PV from Multi will be exportet as well.

Far from ideal but workable.