I need to connect 6 panels in parallel+series. The diagrams I find is about connecting two panels in series and then the 3 (in series) to connect them in parallel.
Is it possible to connect 3 panels in parallel , and then the two in parallel ones to connect in series?
I prefer this, because the 2 of them are in a higher slope, so would like to have one of each in the series connection ..
I would not do this.
The three in parallel would each need to be fused individually so that if one panel develops a fault, it does not suffer overcurrent (forward or reverse) from the power of the other two. That's really for a fault condition.
The next set of problems are every day conditions and would be a big.
So, three parallel panels in series with another three in parallel means three times the current. However, the current is unlikely be shared equally between the two series sets and again one panel from one set might get higher current through it and cause an overcurrent situation.
This would definitely happen if one or two of the panels from one parallel set were shaded and all three from the other set were in full sun. A lot of current would be trying to flow through one or two of the partly shaded set.
Next is the bypass diodes within the panels, these are only rated to carry the Isc current of a series string. Again, they could end up trying to bypass Isc x3 from the other parallel set.
Much better to wire the strings in series and then those in parallel. If you wire 3 in series and parallel just two strings then you don't need to individually fuse those two strings in parallel because the fault current is equal to Isc of the other string anyway.
2 of them are in a higher slope
That's not good, either.
You want all panels in an PV array (all panels connected to a single MPPT) to face the same way and to have the same angle to the ground. If that is not possible, at least try to respect this rule for all panels from a string.
