Combiner Concern

[Panhandlesolar]

Before I do something really stupid I thought I would ask the collective to fact check me.

Here is my equipment, 48 Blue sun 400 watt panels, 2 Blue Sun 2in 2out combined breaker boxes ( thats what came in the kit), then 2 10KW Growatt Grid Tie inverters, 3 MPPTs each.

48 Panels 49.55VOC each, running 6 strings 8 panels per string in Series each string is 300Volts per stings.

My engineering plan does not show a Breaker combiner, instead the engineers call out a basic Junction box, 3 branches in 3 branches out into the corresponding Inverter MPPT’s.

Any advice on combining 3 strings into 2 then separating them back into 3 inputs for the MPPT’s.

Or is it better to bite bullet and buy two new combiner boxes with 3 string inputs and 3 output to tie to the MPPTs.

Appreciate any advice.

 

[svetz]

Any advice on combining 3 strings into 2 then separating them back into 3 inputs for the MPPT’s.

You can split the current by going from one wire to two based on Ohm's law, but not the voltage. See the FAQ entry on panels in series/parallel for more. You can also transform both current and voltage with other devices, but you'd end up spending a lot more than for a combiner box.

Given that it's too easy for things to go wrong splitting the current (e.g., one accidental disconnect and all the current goes through the other), I wouldn't do it this way.