question

lintech avatar image
lintech asked

Multi RS Solar Possible Improvements

I have just installed my Multi RS Solar and have noticed a few features which would make this unit more useful. Most of these features should be available with tweaks to the firmware and VictronConnect app.

  • The battery SOC should be available in the trends
  • AC1-IN relay should be able to be energized on the following to allow AC charging without being connected all the time due to a 250W draw just for being connected.
    • Battery low voltage setpoint (with relay off after time setpoint)
    • Low SOC setpoint (with relay off after time setpoint)
    • High battery current setpoint (with relay off after time setpoint)
  • Battery temperature should be available even if temperature compensation not selected

Also, is there any decent documentation for these units? I feel as though these have been rushed to market without the usual Victron finesse.

TIA.

solarMulti RS
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14 Answers
wkirby avatar image
wkirby answered ·

I did this using the Aux input to disable or enable AC-IN.
I drive the input from one of the relays on the CerboGX and then use generator rules to determine when AC is connected or not.
More letely I have got Home Assistant to drive the relay on the CerboGX. Rules in Home Assistant set the AC-IN power level as well as enable or disable AC input. This way I can charge with higer power during off peak electricity prices.

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @lintech

Oooof - I was and still am responsible for writing the Multi RS documentation so I am taking this one kind of personally :)

Though of course would appreciate some more specific feedback on what you think is missing from the documentation so I can improve it.


Indeed there are several limitations and features still missing (ESS, parallel and three phase, etc), and also especially around the AC input controls, but I disagree it was rushed.


Rather some markets are already able to be served by the Multi RS feature set as it is, and some better served with it now than without it.

Production capacity for new product lines is also limited, so also acceptable that other markets with more complex needs wait longer while that ramps up - especially those already well serviced by our existing products.


There is still extremely active development occurring in firmware and software for the RS range, and potential to join a beta testing group if you're interested in trying new features first and willing to accept the risks/downtime.

If not, if you keep up to date with VictronConnect updates you will also see new features as they released.


Congrats on getting the Multi RS too btw, I use one myself and really like it. I have already seen its feature set and 'victron ecosystem' support expand considerably since first installing it.

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iromeo avatar image iromeo commented ·
I would like to beta test, please :)


Not an installer, but I do help people whenever I can and I do play around whenever I get the chance. I'll "upgrade" my quattro soon (as in sell and buy 3x multis, as I need to combine 3 phases into 1 ACout) so the RS (gen 1) will be redundant in the next week or so and I could play around with it (as it's winter and not much happening)
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semlohnhoj avatar image
semlohnhoj answered ·

I have the Multi RS Solar as well. I really wanted to have the batteries charge at cheap rate at night and have the PowerAssist available all the time so the full 57A mains output is available. The unit doesn't have time scheduling out of the box and programming the ESS registers via Modbus doesn't work as documented (I'm assuming this will be a future firmware update?).

Best option I came up with for now was setting the unit to ESS Optimized with BatteryLife) and then using Macro Scheduler on a desktop PC with the VictronConnect app installed and scripting it to open up the settings page to change the Minimum discharge SOC % value to 80% at night on cheap electric and then setting it to 10% outside that time window. It uses battery during the day and only uses the mains input to supplement this under high loads.


I'll adjust the 80% figure up/down based on the solar charge I get during the day just to keep it around fully charged at some point in the day and also periodically deliberately charge to 100% now and then just to allow the Lifepo4 cells to balance properly.


My point is, it would be nice if the unit did this out of the box as lintech has mentioned.


As for the documentation, I have a few questions:


1) It says the unit will deliver 31A+26A using PowerAssist which I see happening but is there a time limit for this? Should this only happen as a surge or is the unit happy to supply that over a prolonged period?

2) The feed-in to grid seems to be disabled and I want it to be but will it feed-in if the batteries are fully charged and there is spare solar available? As far as I'm aware I've disabled this in the settings and via Modbus but I've not had the solar connected properly yet to check.


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Hi @Semlohnhoj,


ESS Control

Indeed full ESS support for the Multi RS is still a work in progress.

Hats off, that's a very outside the box thinking way to do it. Not one that I would recommend, but might just be the best way to do it for now.


PowerAssist time limits

There is no fixed time limit to that rating, but operating at that current will generate heat, and if the enclosure or environment is unable to dissapate that (due to airflow or ambient temperature) then it will derate, and potentially restart.

There is no harm done in that overload though, the unit may shut down, and then restart. So you can continue to use the Multi as you are, and then adjust behaviour or environment if necessary if that occurs.

This might also be a seasonal adjustment (depending on your location)


Grid feed-in

Grid feed-in is currently disabled, and will remain disabled until there is country grid code support.

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lintech avatar image
lintech answered ·

Please don’t take this personally @Guy Stewart as I am just posting what I see. Having had to write manuals for products myself I am aware that it's easy to expect everyone has the same understanding about the product as the author and that the document is just highlighting the important facts.

However, when I am looking for a product to perform a certain task, I cannot borrow one and put it through its paces before committing to the final purchase. Therefore, I need to have many of my questions answered before placing an order. Both the brochure and the manual only vaguely define the functionality of the product but offer no detailed definition as to options that are available, the associated terminology or the functionality it provides with these options.

When I was looking to purchase a replacement for my $800 Chinese eBay special with something of better quality that supported LiFePo4 batteries I immediately turned to Victron as I have used these products before. But I had no definition to compare some of the functionality that was available with the cheaper counterpart.

If I have missed where it explains some of the terminology of the VictronConnect app I am happy to be corrected.

For example, in the General menu it shows the following:

1665624027535.jpeg

Where is the explanation of the functionality difference of the 4 menu items.

If I select Grid, does this mean that it will feed back into the grid? What’s the difference between Shore power, Generator and Grid.

The manual should contain an explanation for each of the menu items in the Victron app even if the functionality is second nature to the author.

Similarly with the following menu. I as an end user shouldn’t have to work on assumption as to the functionality difference between the following menu items. I can assume, but I could be wrong.

1665624027570.jpeg

The same goes for the ESS menu, what is ESS, I as an end user may not be familiar with the Victron terminology. What is the difference between the following menu items.

1665624027608.jpeg

Currently the inverter does not meet all my requirements out of the box, but I am hopeful that further improvements to the firmware and app will provide this. I can get around certain issues by adding external controls, but if I was quoting this as a job it could leave me out of pocket.

I would also like to know why the inverter draws 250W from the Grid when connected but shows no amps on the status page. This seems a high overhead for simply determining a grid connection, even my Chinese special only required 20W unless charging or supplementing the load.

Also, there is no definition with respect to how the AC or Solar is utilized. Does the PV feed the load first then charge the batteries or does it charge the batteries first and if there is a surplus it will supplement the load. Similarly for the AC input, does this supplement the load first, then charge the batteries or does it just charge the batteries. Is the charging / load methodology programmable through the app based on menu selection.

Can battery current draw be limited if the AC is connected? Even the LED display cannot have the backlight turned off. Is there a roadmap to provide an ETA as to any additional features?

So many questions.

The manual that came with the inverter has references to the Victron RS Smart inverter along with reference to terminals that are not available on the Multi RS Solar. This leads me to assume much of the manual has been cut and pasted from the RS Smart manual.

Maybe being vague is the new marketing methodology, hoping people will buy the product based on assumption rather than facts. Unfortunately, this methodology could leave a bitter taste of disappointment in the purchaser's mouth which may make them look further afield next time they need a similar product.

I have installed a couple of Victron products over the years for people, however, if this was for a quoted job, I probably wouldn’t have purchased it due to the lack of information. But because it was for myself, I determined that I could probably get around any limitations by other means, or if it was a total disappointment I would change to another product and move this unit on.

I am happy to work with Victron and support the development of this product and the documentation if they are happy to take my concerns onboard.


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Hi @lintech

I was a bit tongue in cheek, I am not offended and always looking for ways to improve the documentation. I agree it's far better for a full disclosure (limitations and all).


There is no functionality change to Grid/Generator/Shore Power selection. It merely provides a useful label to some of the other UI elements in the system.



We have some explanation for some of these settings inherited from the MultiPlus Inverter/Charger - https://www.victronenergy.com/media/pg/VE.Bus_Configuration_Guide/en/description-of-settings.html

Though many of the settings are same, it needs to be revised for the Multi RS manual, to reflect the unique layout of the Multi RS menus, and inserted into the manual - I will do that - thanks for the encouragement :)



# Re ESS

I have just pushed a revision of the manual that more clearly defines that officially the Multi RS does not yet support ESS.


While that ESS mode setting exists in VictronConnect for now - I accept it is in a bit of a weird spot while the feature is developing.

This will get greatly improved once the ESS functionality is complete, for now officially it is unsupported.


That one specific ESS mode feature is described here - https://www.victronenergy.com/media/pg/Energy_Storage_System/en/configuration.html#UUID-9da5aea1-7c3d-d801-4a02-ae9feecf6d0f

Once ESS is officially supported this will also be included (and expanded) in the manual.


# Documentation re-use errors

There is some re-use from other documentation (MultiPlus-II, MPPT RS and Inverter RS).

The system isn't a copy/paste though, and it should insert the correct product name variables - I just found and corrected one that wasn't set propertly in 4.11.1 - Remote On/Off Connector. Did you see any others?


Which terminals are referenced but not available?



# Can battery current draw be limited if the AC is connected?

Not yet, this feature will be added in the future with full ESS support.


There is no published roadmap, nor will there be. We do take feature requests and bug reports though, and I have passed on the backlight request.


Appreciate the feedback so far - and any further more you have.



# Unanswered for now

Why the inverter draws 250W from the Grid when connected?

Definition/programmability with respect to how the AC or Solar is utilized.

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fancourt avatar image fancourt Guy Stewart (Victron Community Manager) ♦♦ commented ·

@Guy Stewart (Victron Community Manager) - it's always possible I'm just confused, however I think I've found another (copy/paste?) error in the RS documentation:

In the Inverter RS Smart manual it states "To complete a full charge from solar, connect PV to the internal MPPT solar charger, or another DC MPPT."

Surely that applies to the Inverter RS Smart Solar or Multi RS Solar rather than the Inverter RS Smart, which I understand does not include an internal MPPT SCC?

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fancourt avatar image fancourt fancourt commented ·

And another potential error in the docs for you @Guy Stewart (Victron Community Manager):

In the Inverter RS Smart Solar manul at Section 3.7 it says: "Note the VE.Direct port on the Inverter RS cannot be used to connect to a GX device"

However in Appendix C of the same manual, the diagram shows a GX device connected via either the VE.Can or VE.Direct ports.

In Appendix C of the Inverter RS Smart, the diagram is still ambiguous but does not directly contradict Section 3.7 in the way the equivalent diagram in the Inverter RS Smart Solar does.

The Multi RS Solar manual does not appear to have these errors or ambiguities.


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lintech avatar image
lintech answered ·

Thanks @Guy Stewart (Victron Community Manager) I hope I wasn't too harsh. :)

Thanks for the additional info, much appreciated.

The most important issue for me right now is either reducing the overhead burden (250W) or allowing the AC1-IN relay to be programmed internally via voltage setpoint or SOC setpoint. Ideally if the overhead can be reduced this would be a better solution as this would allow the AC to stay connected and supplement any high loads.

The methodology I would like to have is:

  • Utilize solar as priority, with excess to charging.
  • Battery to supplement if solar is insufficient or non-existent
  • AC (Grid) to supplement loads if, triggered above a battery current setpoint, resumption of battery only on load reduction

Battery charging with the grid connected should be solar only unless battery voltage drops to a low setpoint where AC charging would occur. Other users have indicated the ability to set this via a time window, this would also be an excellent feature. That way if the solar is not great, AC charging could complete the charging at the end of the day or at night (if on a better rate), if solar was insufficient during the day to fully charge batteries.

Thanks again for your help, and I'll be happy to trial any new features that would benefit my installation.


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semlohnhoj avatar image semlohnhoj commented ·

Hi Lintech,


For info, I don't see the 250W burden you are getting. If I'm running in "Keep batteries charged" then it will consume around 20w more on the AC-in than the AC-out. So it's using the AC to power the RS unit. If I set it to "Optimise with BatteryLife" it draws the 20W from the battery instead.


How do you have yours set up when you are seeing the 250w?


This is a screenshot of mine in "Optimize with BatteryLife". No load on AC-out. No solar connected.


screenshot-20221013-132347.jpg

DC wattage is 52Vx0.4A=21W

If you let me know how yours is setup I can set mine in the same mode and see if I get the same overhead.

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lintech avatar image
lintech answered ·

@Semlohnhoj No, it is not displayed on the app. I am monitoring the load via an external meter.


supply-trend2.jpg

I ran it for a while with the AC connected, but external metering shows around a 250W draw. Could have been switching between different settings at the time the AC was connected to see what difference the settings made. In the end I turned the AC off as charging was being done sufficiently with the PV at this stage and I wanted to see how the batteries performed.


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semlohnhoj avatar image
semlohnhoj answered ·

Ah, I see. This could be to do with the way the Multi monitors for a mains failure. From what I understand (and maybe @Guy Stewart (Victron Community Manager) could feel free to correct/enlighten me) but I believe it applies a mains signal at the input with a slight phase difference to measure the interaction between that and the input mains? I Don't know if this explains the 250W and whether it's a real power draw or just your meter that doesn't understand the odd phase/power factor that would be creating? Also, I could be completely wrong :)

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@Semlohnhoj might be correct, one of the ways that the Multi RS tests to see if the AC input is still connected is by 'pushing' the AC sine wave form a little out and sees if there is 'resistance' to it by the external source.

If the external source resists the frequency adjustment then the Multi is happy it exists. This can be visible by some meters as a reactive power factor, but in almost all cases it is not considered 'consumption' and is not charged by utility meters.

The weaker the grid, the greater this distortion can be (and the larger the measured effect). This can occur with thin or poorly connected wires to the Multi from the source, or an actually weak AC supply (often seen in rural areas).

There is further explanation of this in the VA and W section of Wiring Unlimited

If you have a meter that is able display Amps and Volts separately then this measured consumption should disappear. It is only visible when the meter is unable to distinguish between apparent and real power.

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lintech avatar image
lintech answered ·

Thanks @Semlohnhoj and @Guy Stewart (Victron Community Manager) . One more question, if "Optimized with battery life" or "Optimized without battery life" is selected, will the AC input provide power to the load if the battery gets to a low voltage or low state of charge?


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semlohnhoj avatar image
semlohnhoj answered ·

Yes, if you set it to 'Optimized with battery life' then when the batteries reach the 'Minimum discharge SOC' percentage you set, the RS will stop using the battery and just use the AC input. Up until that point, it will use the battery and supplement with AC input as needed.


The logic is slightly different with 'Optimized without Battery Life'. Can't remember how though.



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lintech avatar image
lintech answered ·

Just wondering if there are any firmware updates due as the 250W AC supply issue is still unresolved. I have added an external power meter and it indicates that there is still a 1.36A supply input even if no grid supply is required due to solar supplying all of the required power.

ac-supply.jpg


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wkirby avatar image wkirby ♦♦ commented ·
How do you have it set up to consume the 250W? That power must be going somewhere.

My one has always had a self consumption of about 20W. If the Multi was using 250W it would be getting very hot.

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jeanmarie avatar image jeanmarie commented ·

Look also to what is wired as appliance to your RS !


This could be the consumption of any appliance for which the developer found funny to play with cosphi and having a basic consumption of 20W but with a cosphi of 0.08 like a heatpump Ecodan from mitsubishi.

This item take 1A under 240V but proudly announce 20W of basic consumption : except this value is only for grid connected items, for off grid it is still 250W every hours that is taken from batteries.


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semlohnhoj avatar image semlohnhoj commented ·
My smart energy meter used to read around 7w when the RS was using batteries on firmware version 1.10. Since the latest firmware update to 1.11 it now reads around 20w. Either way, nowhere near 250W. Your unit must be faulty or there is something else in line drawing that power, but you sound like you'd know if that was the case. I'd get the unit replaced.


Just out of curiosity, does the reading go to 0 if you turn off the RS?


I've started using generator rules on the Cerbo GX to disconnect the mains input unless there is significant load on the AC out of the RS and also scheduled it to connect overnight to charge the batteries. It's a bit of a complicated setup but it leaves me off grid except for charging and when there are large loads in the house.

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lintech avatar image
lintech answered ·

@Semlohnhoj I normally don't have the AC connected due to the 250W consumption and just let it run on the batteries and solar, although it's not the setup I wanted. Yes, the current goes to zero when the AC is off and there is no additional load of this breaker as I wired this myself.

Sounds like you can get it to work correctly with the Cerbo GX although I believe this should not be required. Looks like I might have to spend the money to get around the firmware shortcomings. If its all right with you, I might ask for some settings info when I get one installed. If nothing else, I will be able to connect Citect or Ignition SCADA to this unit via Modbus.

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lintech avatar image
lintech answered ·

@Semlohnhoj Just an update on a mistake I have discovered which I have posted on another thread. (Excerpt below)

.... after reading your comment I went back to the external meter and checked the values and was surprised to find the values as what would be expected. Watts were 5.6W, Amps 1.16A and PF at 1.00. I now understand where I got the values from. The 250W value was viewed from a completely different metering setup which still shows 250W even though the external meter is showing 5.6W. Had I looked at the watts on the external meter I would have noticed it was 5.6W and that the other metering setup shows 250W. This must be its lowest value displayed on any value above zero and below 250W. A classic example of making assumptions based on incorrect data, I concede, my error.

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frankmsc68 avatar image
frankmsc68 answered ·

Hi everyone,i would love to see a feature,even if it is possible for an external advice to be controlled: Eccess power from pv: The Multi RS Solar is not feeding into the grid-which is fine by quite a few -but in that case it would be amazing to have the control over access pv power on board,as the statistics would be able to take this into account....I have uploaded a relay board and a possible programm and for years i have no problems with that: 3 independent relays are controlling a water heater with three heating elements,one kw each,with a total of three kw.Battery charging is slightly reduced,to have as long as possible a minimum pv power reading to start relay one.Once relay one is on-in base of the timer-start to switch relay two and then relay three.With a long enough delay off-when a cloud comes-you avoid to have a constant switch on-off or a possible lose of pv surplus.

Another option would be the stop the AC 2 output only if there is no pv power?

IMG_20231124_153430.jpgIMG_20231124_153523.jpg

thanks Frank


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frankmsc68 avatar image
frankmsc68 answered ·

Hi there,would be great to have 2 mppt's with each 4 kw....15AH each and 20AH short circuit.

There are different data sheet settings on german/english where one states 13AH,the other one 18AH? Anyway 4Kw mppt's would be,like the Multi Smart ?

thanksFrank

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semlohnhoj avatar image semlohnhoj commented ·
There is a single MPPT version which is 4KW and a dual MPPT version that are dual 3KW. Is this where the difference in the data sheets comes from?
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frankmsc68 avatar image frankmsc68 semlohnhoj commented ·
@Semlohnhoj :hi there,no ,the data sheets were for the Multi RS Solar dual tracker:one in german,the other in english.The englsh data sheet states 13Ah per tracker,the german data sheet 18Ah per tracker.Anyway two trackers with each 4 kw for the Multi RS i would be an advantage ,if you think let's say 2kw for charging the batteries and over 5 kw for AC out gives you already 7 kw,I have slightly overpowered keeping voltage and ampere under the max.,though in my existing system.This allows me in the winter months to still charge my electric boiler as well as keep batteries fully charged.

Another thing i wanted to clear if the AC out2 turns off only if the inverter switches to battery mode-if there is no pv power and no ac grid?This is also stated (like this) in the german data sheet.

I am thinking of bying the multi rs solar,but still got a bit a problems with the different parameters stated in the different language datasheets.

Great to have the forum for al those interesting comments!thanks Frank

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Mutli RS Solar Datasheet

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