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Looking for some advice and experience here.

I currently have a 3kw grid tied FIT system which will remain untouched. I am wanting to add to this a 5+kw system between the main grid and consumer unit that can largely operate off grid and pull from the grid when required We get power cuts in winter so the DC switch to isolate from the grid is a must.
14 panels of 405w, 13A and 37v Voc are available for connection. 5.67kw total
Looking for simplicity and bang for buck.
- 10 to 15kw of battery.
- 11kw output A2A heat pumps to be installed (circa 3.5kw peak)

Inverters I am considering:
- 5kw Victron Easy solar 48v. (Compact install)
- 5kw Victron Multiplus 2 48v
- Sunsynk 5kw. (Cost effective)
- SUNSYNK 8.8KW.

Any input as to why I would choose one over the other.
From what I can see, the Victron supports a higher output current of 50A versus about 25A from the sunsynk on the UPS load.
The cost basis of the Sunsynks looks hard to beat....

Additional info. I am aiming to install this vertically on an end gable with space for 14 panels.
Ideally I would be aiming for 2 strings of 7 panels in series, paralleled.
This appears to be some of the sticking point, one unit does not appear to support the current if paralleled and the other does not appear to support the overall o/c voltage. I don't really want to remove 2 panels to fit the inverter and end up with 12 panels.

I would have to use both MPPT on the sunsynk with 7 panels on each.

The easy solar would require 2 parallel strings or even 3.

Maybe the Victron Multi RS Solar? 450v Max

Or just change panels / configuration? 37Voc x 7 = 259Voc which rules out the other Victron 250v MPPT's the max voltage is a hard limit and will end in magic smoke if you go over it.

Have you considered using just 12 panels to your inverter and having 2 panels directly charging the batteries via a charge controller?

4 serial then 3 parallel is something I would consider.

With extra panels going directly to the batteries.

The attraction to the multiplus is future expansion. The deal on these at the moment is effectively £3-400 off normal prices as well.

Fueltheburn wrote: ↑Tue Sep 26, 2023 11:01 pm The deal on these at the moment is effectively £3-400 off normal prices as well.

What deal is this, I’m tempted to get another Multiplus.

Jinx wrote: ↑Wed Sep 27, 2023 5:42 pm

Fueltheburn wrote: ↑Tue Sep 26, 2023 11:01 pm The deal on these at the moment is effectively £3-400 off normal prices as well.

What deal is this, I’m tempted to get another Multiplus.

Either a free Cerbo GX with your Multi (don't see the point, the Multi with built-in GX is more compact if you don't need the extra inputs etc) OR for the 3-phase market 3 Multis for the price of 2

Fueltheburn wrote: ↑Tue Sep 26, 2023 7:56 pm Looking for some advice and experience here.

I currently have a 3kw grid tied FIT system which will remain untouched. I am wanting to add to this a 5+kw system between the main grid and consumer unit that can largely operate off grid and pull from the grid when required We get power cuts in winter so the DC switch to isolate from the grid is a must.

Inverters I am considering:
- 5kw Victron Easy solar 48v. (Compact install)
- 5kw Victron Multiplus 2 48v
- Sunsynk 5kw. (Cost effective)
- SUNSYNK 8.8KW.

Any input as to why I would choose one over the other.
From what I can see, the Victron supports a higher output current of 50A versus about 25A from the sunsynk on the UPS load.
The cost basis of the Sunsynks looks hard to beat....

To my mind that was the key advantage over the Chinese brands and if you have regular power cuts I think worth paying for, as the changeover is instantaneous and fully automatic. In fact you might not know it has happened, I am thinking of adding a pilot light on the grid side.

Move yr exisiting FIT inverter to the output of the Victron and it will keep going in a power cut. Don't understand your comment about DC switch. A changeover switch so the CU can take from grid or inverter is very useful though, or you can automate with a contactor so if the inverter dies while you are away the freezer still works.

10 kWh battery is just about enough for us as in the winter we cook on the AGA, would need 15 if still using electric cooker.
Neither will make a dent in the consumption of an HP, I plan to add it on the grid side (but still after the utility's meter!), then it will still have first dibs on any surplus before it gets exported.

https://www.bimblesolar.com/offgrid/inv ... ecial-2023

I went with the 5kv and cerbo fo £1080 delivered to Scotland.
More expensive than the sunsynk but it's the product range that swung it for me.

It can sit in the corner for a while now waiting for other parts to accumulate.

sharpener wrote: ↑Wed Sep 27, 2023 9:31 pm

Jinx wrote: ↑Wed Sep 27, 2023 5:42 pm

Fueltheburn wrote: ↑Tue Sep 26, 2023 11:01 pm The deal on these at the moment is effectively £3-400 off normal prices as well.

What deal is this, I’m tempted to get another Multiplus.

Either a free Cerbo GX with your Multi (don't see the point, the Multi with built-in GX is more compact if you don't need the extra inputs etc) OR for the 3-phase market 3 Multis for the price of 2

Thankyou, unfortunately not useful to me, I have the Cerbo and really am just after a 24v Multiplus as I’ve picked up some more batteries.

sharpener wrote: ↑Wed Sep 27, 2023 9:31 pm

Move yr exisiting FIT inverter to the output of the Victron and it will keep going in a power cut.

I thought with an ESS arrangement the FIT stayed of the output side, as you say, but wondered how the Multiplus coped in a powercut with the FIT system. Once the batteries are full my FIT system exports but in the absence of somewhere to export to won't the voltage just rise and trigger everything to shut down?