Yes.Is a combination possible: Some other type of PV inverter, to charge the battery directly, and to power the SI from the consumer battery, that's not bad either, if it can.
How I imagined it to work: SI to make its own network (off grid) the battery would be a forklift (acid) 800+ah,some other dc controllers to charge the battery directly from the PV system,or SB to SI connect...actually, it is absolutely irrelevant to me whether it will be SB(ac) or some other dc controller? Or I didn't think it through well? my small farm has to have electricity 24/7...!Yes.
The SI is a battery inverter/charger. You will need a BMS. REC is expensive but has a good reputation.
The SI is also a grid forming inverter. Which is important for an ac coupled off grid or backup system that has grid tie inverters. My 2 SI plus the sunny boys can provide 24kw to the house when the sun is shining.
If you use separate DC charge controllers (and you can) I'm a little fuzzy on how the BMS works.
My system will use about 1kw of the panels through a DC charger for a couple reasons. That charger will not receive BMS info and will not fully charge the batteries.
It's more of a "helper".
AC coupling has quite a few advantages, flexibility being one, it's easy to add on to. couple drawbacks like the black start problem if you mismanage your battery charge level.
SI SB is not so great if you are under restriction of how much AC you can send to the grid. All the excess production is either all going to the grid or none( off grid).
The SI internal transfer switch is undersized, I power the whole house either from the grid or via a backfed interlocked breaker. This is not automatic.
You have it right.How I imagined it to work: SI to make its own network (off grid) the battery would be a forklift (acid) 800+ah,some other dc controllers to charge the battery directly from the PV system,or SB to SI connect...actually, it is absolutely irrelevant to me whether it will be SB(ac) or some other dc controller? Or I didn't think it through well? my small farm has to have electricity 24/7...!
Thanks for the quick reply, I have a utility network, which has not been very reliable in the last 8-9 months, I prefer an off grid or hybrid system, I have forklift batteries at my disposal.I would also like to transfer part of the house to that new system. (ligh, refrigerator, freezer...)
the idea is SB6kw and SI8.0 48v 800+ ah
there are doubts about the SMA device, everything is explained very vaguely, there are no diagrams, everything is.....
money is not important for now, what is important is that the farm is working, which is a source of income....
How I imagined it to work: SI to make its own network (off grid) the battery would be a forklift (acid) 800+ah,some other dc controllers to charge the battery directly from the PV system,or SB to SI connect...actually, it is absolutely irrelevant to me whether it will be SB(ac) or some other dc controller? Or I didn't think it through well? my small farm has to have electricity 24/7...!
SI doesn't care if it charges the battery from SB, or if another charger does as long as the charge and discharge current pass through the ( external) shunt.
My point was I guess that an off grid ac coupled system can handle higher loads when the sun is out. May or may not matter to you.
Did I understand correctly or not? The recommendation is SB and SI? That combination seems to give me the least headaches. A little later I will go to take a picture of the battery. I saw it on the link, but I try to avoid the diesel generator, and the city network is almost non-existent.....the idea is off gridYou could have 2x Sunny Boy 6kW with one Sunny Island 8.0H, 12kW can pass through to grid (or be used off-grid.)
Sunny Island will disconnect from utility grid when it goes down and make an "island" grid.
Internal transfer switch isn't so undersize for the European model, because 50A at 220V is more power than we get at 120V. I use 4x SI wired 2p2s on account of that.
With AC coupled Sunny Boy, Sunny Island can adjust Sunny Boy's output to hit a target charge rate, (e.g. 0.12C if appropriate for FLA), and request more current from Sunny Boy when used by loads.
DC coupled charge controllers will put as much current as they can into the battery, unless they use battery shunt to throttle back power. Sunny Island used to tell SCC what target voltage, don't know if it does with these new models (assuming Sunny Island Charger, or Midnight Classic with a data interface.) Sunny Island does not command SCC's charge current.
If you mix DC coupled (not too much for battery) and AC coupled, Sunny Island will adjust AC coupled power production so that plus DC coupled (as measured by shunt) hits target charge rate.
I think SI communicating with BMS will adjust charging from AC coupled PV as requested. Don't think it can do anything with DC coupled except change target voltage, and then only if it communicates with BMS.
I recommend Sunny Boys. Also a "load shed" relay or two, which would disconnect loads at certain state of charge.
I have US model 5048US, 6048US, several model Sunny Boys, and Sunny Island Charger SIC-40. Also Sunny TriPower.
I've never used the new European model 8.0H, or the newer Sunny Boy -40 or -41.
It is good to keep the grid, because you can avoid cycling the lead-acid forklift battery except when grid is down. Or does FLA need to by cycled, to keep it stirred? Also, if battery large enough for 3 days autonomy without sun, would only cycle 15% at night, should be able to last 20 years. In my case of undersized AGM (cycles 70% at night), I want to keep it at float.
Diagrams?
I find some, but now I'm questioning whether 8.0H can do grid-backup without an external relay. You're going to have to figure that out yourself, I'm afraid.
Sunny Island 4.4M / 6.0H / 8.0H | SMA Solar
www.sma.de
Sure. I have two Victron MultiPlus-II 3000VA inverters running in combined 240v mode. I also have a couple of victron autotransformers providing 120v output.Could you provide some details like brand and model of inverter and battery bank? I don`t know what an assist function is .
Did I understand correctly or not? The recommendation is SB and SI? That combination seems to give me the least headaches. A little later I will go to take a picture of the battery. I saw it on the link, but I try to avoid the diesel generator, and the city network is almost non-existent.....the idea is off grid
SI-LS100-48 | Load Shed Contactor 3 Pole 100A (non inductive) 48V DC Coil | £95.15 |
Thank you very much, the return of the utility network is not a problem, I also have a charger from a forklift . All I need for my farm to work is: SB-SI and battery (I have uploaded pictures) I have two such batteries.......If I understood correctly: SB would provide power for SI network and battery charging, the rest is not important.Yes, SB with SI works well.
I'm not certain the European 8.0H model works for backfeed of utility grid by itself, might need an external transfer switch? But for offgrid, and generator backup, should do all you need.
I recommend also a load-shed relay, to disconnect loads but keep SB connected if battery gets low.
SI-LS100-48 Load Shed Contactor 3 Pole 100A (non inductive) 48V DC Coil £95.15
Thank you very much, the return of the utility network is not a problem, I also have a charger from a forklift . All I need for my farm to work is: SB-SI and battery (I have uploaded pictures) I have two such batteries.......If I understood correctly: SB would provide power for SI network and battery charging, the rest is not important.
I forgot to ask: is SB only compatible with SI or is there another inverter of another brand? I am also interested in the SB tripower, could I include it in the combination, because it is three-phase?