Limit Multiplus current and AC-in connected solar (combined) for external breaker box

DIY
, , , , , ,
1

I would like to install a small ESS system (3000Va 10KWh) and would like to use current cabling.

The system id like to make will have a 3phase 25a grid connection with 2.5mm2 to the inverter room. Grid metering will be done by a Victron meter at this grid connection.

1phase of this grid connection has solar installed with a 2.5mm2 cable to the inverter room with a B20 300Ma RCBO

In this inverter room id like to install a Multiplus parallel to my Solar inverter. (I know its not optimal but it uses the current cable connection)

Solar peaks at 2500Va, Multiplus at 3000Va making 5500Va. A 20A RCBO can handle 4400W.

So id like to use a external power sensor on the multiplus to check the current on the 20A RCBO cable from the external breaker box Current Transformer for MultiPlus-II - Victron Energy

Can I combine the grid meter for DynamicESS, while still using the external sensor of the multiplus to make sure the breaker doesn’t trip?

Connection:
GRID (metered by Victron EM) >>> B20 0,3 RCBO >>> 2,5mm2 with Multiplus current transformer clamp on it to meter this wire for current limit inverter+solar >_> 16A 0,03 RCBO with multiplus (current transformer connected here) +++ 16A 0,03 RCBO and Vitron EM with solar

Im afraid the CurrentLimet will be disabled if I meter at the grid as well? Or wil the multiplus internal CurrentLimet still be active?

THANKS!

2

Image for some more clarity:

IMG_3469.HEIC
IMG_3469.HEIC2016Ă—1512 824 KB

edit:

  • the solar inverter will include a victron EM meter as well
  • 3phase main switch connects to grid
3

How long are the wires? Are those longer than 10 meter?

Having a (Victron) meter connected without any kind of protection right after the main switch, is not a good idea.

You could use two CT’s on one 3-phase meter. One for net metering and one for the solar.z

Are you familiar with Node-RED? I mean. You could use Node-RED to read the meter values and set settings accordantly to what you need.

1 Like
4

I installed the MPII in a different area of the house.

I decided to use the clamp meter (victron current transformer for MPII), to maximize the load for a 20 amp breaker sharing the multiplus with a EVCS.

Although the location is different the concept is the same.

Everything functions accordingly, although there is one thing that is kind of weird:
The clamp meter connected to the multiplus thinks everything going trough this clamp is a “critical load” inside VRM. But the measurement is correct inside the Remote Console.

ESS has been set at “loads only connected to AC IN” because of this, only phase1 (3phase grid) shows 0 watts of the wats used by the EVCS under “AC Loads” inside VRM but phase2+3 show there usage. They will show at “Grid” in VRM (Critical Liads do not display when ESS is set to only AC IN).

The clamp meter is connected to the multiplus as per manual, and it’s set to external meter inside VE.Config

I’ll try to make a screenshot of this behavior the coming week.

Although the presentation inside VRM is a bit off, it works as it should. It limits the total amount of energy shared with the EVCS to the 20amp set inside VE.Config by reducing the charge current of the MPII when needed.

All the usage reports (energy, schedule, cost and earnings) inside Dynamic are correct as well.

So except of the wrong display under the VRM realtime data, everything works fine.

5

I also tried using Node Red for the same result, it could be done. But realtime measurements done by the multi itself sounds like a more reliable way to do it.

I’d rather would have used node red to reduce the current of the EVCS on only phase 1, giving phase 2+3 the full 16 amp (if available from grid)

But when Dynamic ESS starts charging the battery reduce the current of the EVCS phase 1 to 10 amp leaving plenty for the Multi to charge at their full 35a@52v.

As far as I know you can not control one phase of the EVCS.