I need some guidance on identifying the best setup for my use case. Here it goes.
At the moment I have a 3 phase solar system grid connected with a Huawei Inverter 5kw (using 2 PV string). The price of the fed in energy is so low now that I am thinking that batteries are needed for me, but the Huawei ones are very expensive so I decided that it makes sense to switch to Victron, at least I will have the flexibility in the future to adapt the system how I want and have a better quality one.
With Victron I have limited experience, I have made an off-grid system for my caravan but that’s it.
I was thinking to buy 3 Victron Multiplus II 48/3000 connected to 3 MPPTs 150/45, and to buy a 4x12v/100A batteries in the beginning and to expend later on.
Is this a good, efficient setup for a grid connected setup. I was also thinking that with this setup I will just take down the Huawei.
My expectation is that I consume what I produce, when required use energy from the batteries (during the night, cloudy days etc), if power drops (it happens quite often where I am from) I can still have the house running, and excess exported to the grid
Are there any better products, or better way to do this?
Regarding your choice of battery: wouldn’t it be better to buy a 48V (51.2V) battery? If you buy 4x12 batteries you have to connect them in series to get to 48V and it is so much easier to just buy a 48V battery.
The best option is to go with batteries with 16 cells mostly denoted as 16s1p to arrive at 51.2V. There are also some batteries with 15 cells - 15s1p - and they have a nominal voltage of 48V, but then you have to be very strict with all the voltages. I prefer 16s1p.
How did you do the dimensioning of your Multiplus-inverters? How did you arrive at the 3000 version?
Same question for the MPPTs? How did you do the dimesioning, i.e. how many panels per MPPT/string, …?
I might be wrong with my calculations, so take this as the experience of someone with DIY skills and not a professional but…
at the moment I have a 5kw inverter connected to two panel arrays of 3.2kw each. Since the 5kw inverter serves the 3 phases, I figured that replacing it with 3x3000VA would get me an equivalent of 7.2 kw in terms of inverter. That it clearly an upgrade, and a plus to this would be that I could connect an extra MPPT, das I can add some more panels on different side of the roof.
regarding the MPPT I think I have made the wrong calculation. I have to think about that a bit more! I will come up with some details once I decide what’s best/cheapest.