RS Smart Solar - can I set AC Charge Current?

DIY
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1

Hi all,

Looking into a RS Smart Solar to replace a failing MPP.
Comparing this with a MultiPlus II I don’t see the option to set the charge current from AC. Just what I believe the max (total? PV?) charge current.

Hence my question, can one set the max AC charge current on the RS Smart Solar? ( PIN482601000)

Reason is that I do not want the inverter to charge batteries from AC at night.

Inverter will/is the second unit on the house, main unit just feeds back into grid.

This unit, with 10kw lithium batteries will power continues loads like fridges etc and the airconditioning.
Once power consumption is to high or batteries to low, it will need to switch to use AC. Then back once power at reasonable level and/or batteries at decent level of charge. I (believe) it can do that, but what i don’t see is the option to limit or switch off charging from AC, specifically if it’s switched to use AC.
Charging at night from AC would/will be opposite what I want.

Cheers from Perth!

2

Hi SunnyPerth,

The RS Inverter range is primarily designed to work off-grid. However, it is possible to run external AC PV inverters with it, as detailed below.
Inverter RS Smart Solar 4.2. Connecting to external AC PV inverters
Dave

3

Hi Dave,

thanks for the response. Yes, good thinking, but realistically I’m not allowed to mess around with my already installed grid-connected PV installation & that is a 3 phase system.

I also don’t see how this would solve my challenge with limiting battery charging if/when the system is AC connected.

For clarity. System normally would work in an off-grid mode. Using 2x2kw in solar panels, 10KW of batteries. But there will be times that either the load is too high (short periods when air-conditioning starts up in summer) or batteries are low. At this time, I like to switch the inverter to AC. (conditional AC input connection, based on load and SoC / Voltage)

But - what I like to prevent is that at those moments, AC is being used to charge the batteries.
While in day time that might be fine (as I’m also exporting to the grid from my other system) - At night it would mean I charge from AC & Importing energy.

IF the inverter is connected to AC - then changing the current limit for AC input won’t be a good idea, I will need that to run the Air-conditioner. I could change the max charge current, but since that’s for AC + PV, it means that PV goes to waste (if there is)

I’m thinking for this use case, I might need to get a Multi Plus II GX, with two Smart Solar Charge Controllers. These smart controllers will charge batteries from Solar, regardless what the inverter does. And I can set the inverter connect AC once load is high or batteries are low; with a low or zero charge current. This will stay then that way, until the load drops or batteries are recharged (by solar).

The challenge is that the Multi Plus II GX 5000 model has a lower max power output, the next model up (MultiPlus II 8000) is almost twice the cost and I need to get the Cerbo separate and still ned to add the two Solar Charge controllers. The RS Smart (without solar) and two solar charge controllers, which would allow me to do the same as the Multi Plus II GX example above, is again a fair bit more expensive.

–

What happens if you set the max charge current set to 0, and there is more PV in than being used by the loads? (not AC connected, not ESS) ? I guess the energy won’t be used correct ?

Cheers,
y.

4

Ypu don’t mention if you want a three phase victron install on the three phase pv install?

The way around that is varying the soc during use.
If you don’t want to charge freeze or set the min soc at that level.
Or you could have an energy meter in at the ac input before the three phase ac pv and have a grid set point of zero.

With Multi rs you can also switch the system to passthrough.

There are many ways around not charging from grid.

The system then goes into passthrough. and depends on your components.

Another way the charge current control assistant on the MP2.

5

Hi Lx,

No, just looking for single phase install here and it’s not going to feed in the grid. Forget (for now) the fact that already have 3-phase system that puts energy back in the grid. Not really applicable for this discussion.

This inverter will be there to power my aircon, fridge and a few other (low power) devices. This unit can’t feedback into the grid either. Simply not allowed.

Let’s say it this way - when in pass through mode (AC IN connected to AC Out), I want the inverter to only charge panels from PV.
I don’t see this as a setting in the manual of the various inverters, the only setting is Max charge current, which is for PV and AC. As I don’t have a Cerbo GX, I don’t know if you can set it there.

(With my current simple-cheap-MPP-Solar system (that is breaking down slowly) I do have the option to set both AC charge current and PV charge current)

Hope that explains what I’m trying to achieve… it’s not just that I want (total) charging to be zero, I want the AC charging to be zero (at times that I direct it to). (When it’s in pass trough mode to be specific, there will be load on the system at those times)

Cheers,
y.

6

It would be easier to do it with the cerbo.

For the multi RS

Passthrough will do that for now.

This is easier to do with variable min soc settings

If you open victron connect in demo mode you can see some of the settings there.

For the ve bus products you can do all that through the cerbo as well. And even automate it with scheduled charges.

7

Sorry, what will do that, for now? As I understand passthrough will charge via the max charge current set. (obviously it would only charge if battery is not at max SoC/Voltage set).
Is that correct, and what you mean?

If that’s the case, and it’s in day time, in passthrough, and I set the max charge current to zero, then the system would still not charge from PV correct?

And as soon I increase max charge current, to allow charging, in passthrough, it will use PV first and then rest from AC until max current is reached. This is where I like to limit the amount of charging from AC IN. Give PV free range, but AC zero or limited.
(and in day time this is less important than night time, as there is sun and my second system supplies a bit of that energy. But at night neither is there, so it’s pure AC in then). (unless I change max Charge current to 0 at night, I understand that bit)

[I’m in the demo mode in Victron connect - but don’t find a combination to achieve what I’m looking for ;-). Understand that I can do way more with Cerbo - but don’t have access to one so bit of a dark art for me at the moment)

8

All right… I slowly start to understand (dangerous remark, I know) the advantages of ESS.

I found this post, specifically this line :

The Multi RS will be aware of the loads between the grid and the AC input, and if the Grid meter is correctly configured, and will supply power to them without feeding into the grid.

There is not yet grid code support, so feed-in is not yet permitted.

There is a 10W power draw added from the utility grid: this is a safety margin to compensate for measurement inaccuracies to prevent feeding energy into the utility grid.

So, I can connect the Aircon back to grid, use energy meter to understand how much energy the aircon uses, and let the Multi RS Solar supply that energy (-10w)

Looking at the ESS manual - and updating the first example installation would like :

image
image595×617 31 KB

  • My existing Grid inverter - leave as is.
  • Move aircon from (now) behind inverter back to grid.
  • Enable ESS without feed in option to supply energy to aircon

If I can do that, that is a WAY better way to design what I need.

Question now.. the Multi RS Solar is not (yet) certified for feed-in in Australia. Now, I don’t want to use it for Feed in, but wonder if it still will work? to supply power to the AC loads without feeding into grid?

Cheers,
Y.

9

Note that I do have a 3 phase connection, the existing inverters (feed in, left top in picture) is connected to 2 phases (2x2.5KW = 5KW total). So if it gives problems to have the inverter there, I can connect the Multi RS to the 3rd phase? (IF)