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mmx01 avatar image
mmx01 asked

Total AC output power EasySolar II GX 24/3000

Hi,


I plan to use EasySolar II GX 24/3000 to power a small cabin. Typically the AC load is not very high +/- 1000W but on occasion I may have heater and electric kettle on which adds to about 4000W.


My question is, is it mandatory to get 48/5000? Or perhaps 24/3000 would still work because power limit is only for DC->AC converter and I could still draw another 3600W (16A) via ACin mains connection. Here I am not that clear about overload conditions vs. combining ACin (3600W) + DC->AC (3000W) out for a total power of 6600W in short moments with these high power loads on.


The system will be EasySolar, 2,2kw solar, 2x280 24V LifePo4 battery. I read that EasySolar is combination of few other systems like MultiPlus II + MPPT etc. In theory I can go to 48V with batteries in series but I already have 24V stuff and prefer to keep the system at 24V.


Thanks in advance,

Mariusz

powerassist
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4 Answers
matt1309 avatar image
matt1309 answered ·

Hi @mmx01


I'm not familiar with easysolar but multiplus ii manual comments on this exact scenario.

And im pretty sure easysolar is really just a multiplus ii + mppt isnt it?


Assuming you have a grid connection (with ESS or power assist setup i believe). Then you should be fine. The manual explains it from point of view of a 3kva multplus ii.

MultiPlus-II 230V (victronenergy.com)

Page 14 in the above (AC-out-1) section.


EDIT:

Found in easysolar manual same page number

EasySolar-II GX - Product Manual (victronenergy.com)


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mmx01 avatar image
mmx01 answered ·

@matt1309 this is excellent! Indeed currents add up. Please let me know if I understood this right.


I connect mains to AC in and the rest of the system to the inverter.

Since I do not plan to feedback anything to the network nor applying for any permits certificates, need to set zero feed-in options. It also says I don't need meter to make it work. Correct?

Grid Feed-in :

AC coupled : disabled

DC coupled: disabled


Enable ESS assistant, do not enable PV assistant since MPPT is DC coupled and not AC coupled.


Then to maximize solar usage I use Virtual Switch - Ignore AC:

- Load conditions: >2800W for 10 sec & < 2500W for 60 sec -> system will not use AC below 2800W just solar + battery. When load goes >2800W AC in helps with the load.

- Battery voltage: <25.2V for 60 sec -> system will start charging battery and providing assist on low battery.


Is there a way to set priority between solar and battery? Looks like ESS in Optimizer mode works like that: Yes. ESS will reduce grid usage to a minimum, preferably to 0W, with or without feed-in enabled. It keeps the MPPT Solar Chargers working hard - even when the batteries are full. -> So the answer seems to be as long as solar has enough power it will provide load first and then charge battery?


It is a very complete system but a bit difficult to understand interlocks between different parts/document at first glance.

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matt1309 avatar image matt1309 commented ·
Hi @mmx01


One to watch out for is you may technically need certificates given you're connected to the grid even if feed in is disabled (depend where you live). But i've heard of a lot of folk who risk it given it's difficult for anyone to even know you're connected without inspecting it.


Assuming you have no loads on "grid/ACIN side" that you want the inverter to cover then no need for a meter, the inverter has an internal CT clamp that should capture that data.

Tbf that is one other solution thought. You could wire high usage loads on ACIN side and have ET112 or another supported meter before them

ie grid -> meter -> highloads -> inverter -> normal loads.


If the inverter can it'll backfeed just enough power to cover the highloads in this setup. However this can be a messier setup given you'll need two distribution boards one for loads on ACIN side and one for loads on ACOUT side.


I believe virtual switch is not possible to use with ESS assistant enabled but again not 100% on that. Setting grid setpoint in ESS settings on gx device to 0 should accomplish what you're looking for.


ESS will prioritise battery/solar unless the state of charge of the battery drops below the minimum you set in ESS settings on the GX device.


MPPT will only ramp down output if grid feed in is disabled and batteries are at 100% ie power has no where to go (If you dont want export to grid in this scenario then you could even program an immersion/water heater to turn on if this point is reached using node red).


I agree it's a massive amount of functionality to wrap your head around. Up side of Victron system is if you can imagine a configuration it's probably supported but does mean it can be a lot of reading to understanding all the features.




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mmx01 avatar image
mmx01 answered ·

I have currently not so potent Growatt SPF3000TL. It is stated this is an off-grid inverter so technically it does not feed anything back to the grid and off-line installations do not need registration. Yet it packs an AC charger so it is connected in some way...


So it is very muddy if this is already grid connected or not. We can connect any AC charger to charge batteries without reporting it as long as it has CE and therefore won't disrupt the grid etc Being in Poland I see fascinating grid code discussion re. Victron as well. Someone over complicated few things I imagine but the time will tell.


Interesting if an isolation transformer physically separating the grid and the load (grid ->Victron AC in) puts this issue to bed altogether. 4kW units are not terribly expensive and this is galvanic separation so... nothing is connected at all.


I prefer to not have anything else on the AC IN side. Grid disconnect among anything else is a safety feature. Criminal charges carry some weight if something does not work there.


Will test either of options ESS setpoint 0 or virtual switch. I didn't find anything in the docs about it being disabled when ESS is on, but it does say not to use ESS when Ignore AC is to be used. Okay, but then what to use?


Hmm I'd love just a simple mechanism do not use grid until load is high or battery is low - say 20%, then use the grid when load exceeds inverter rating or battery is low.

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matt1309 avatar image matt1309 commented ·

It'll likely depend on your countries regs.

I think the theory that mechanism is ESS.

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mjs500 avatar image
mjs500 answered ·

3kva x 0.8 = 2.4 Kw or 3000VA x 0.8 = 2.400 w

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mmx01 avatar image mmx01 commented ·

Don't quite get what this refers to? How this relates to grid rules or ESS (off-grid/on-grid)?


a) 2400 W =/= 2.4000 w, one zero and a dot too many

b) question was about going above inverter rating of 3000VA, which power assist with ESS provide altogether. So whether that would be cos fi 0.8 or 1.0, the question was about going above > 2400W or 3000W.

c) not to mention 0.8 is a faaaar stretched calculation where you seem to miss load characteristics... resistive loads like electric kettles, irons, water heaters, boilers have (cos fi) 1.0 so it is 3000W or 3kW for 3000VA




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ejrossouw avatar image ejrossouw mmx01 commented ·
ESS is NOT off-grid even if you don't feed excess in. Consider using no grid code with AC ignore then the ACIN will remain open and you can power loads from solar and batteries. Then set a condition to have it switch to grid when an "overload" occurs and power all loads from the grid (no inverting) and back when the overload has gone. PS - Powerassist should not be confused with the function that can support a weak shore supply with batteries. The inverter output rating plus the transfer switch rating is the total amount of power available to loads when using ESS.
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mmx01 avatar image mmx01 ejrossouw commented ·

Thanks. Can I also cascade two MPII one connected to the grid with ESS disabled, the other one connected to MPII AC 1 out (technically seeing MPII as a grid) with ESS enabled? I then could double the load of cascaded MPII providing for the loads.


Benefits, one could use two different versions of MPII, separate battery banks etc. since that's not a parallel system.


Looks to me this should be grid compliant as ESS is effectively operating behind another inverter.


https://community.victronenergy.com/questions/257362/total-ac-output-power-easysolar-ii-gx-243000.html?childToView=261520#comment-261520


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