DISCUSSION: PV Series vs. Parallel. Is parallel REALLY better for partial shading situations?

[Hedges]

But in 4s2p one shaded panel was knocking out the entire string, so I was loosing half of the power. Even when I tried shading 1 panel in each string power output was greatly reduced. I guess because of some V unbalance.

One shaded per string, should have put out the power of 3s2p. If it didn't, would check minimum MPPT voltage and bad diodes.

 

[Hedges]

But recently I was thinking about TS4-A-O optimizers. I wonder if they will allow me to increase an output a bit (for single string config)?

I would only expect optimizer to help for an off-angle panel, putting out less current.

Also I'm a bit worried about bypass diodes "health". What would be your recommendation?

Shade on a panel when others in string have full sun forces full current through it, may cause failure. Best if this only occurs when sun is off angle.

One question about Optimizers bugs me: Can I do something like 6s2p config with individual Optimizers on each panel, so that they can re-balance V in each string?

If 6s is off angle from other 6s, voltage still quite similar. Separate MPPT per string was found to only increase production 2%, so I doubt optimizers help any.

This way I could get same thing as what I get in a single string config - exlude only shaded panels, not just entire string if I have 2-3 panels shaded in either of the strings? I couldn't find an answer on Tigo's web site. I assume Optimizers are DC to DC converters, but do they have enough "intelligence" to do string balancing?

If you had 6s in full sun and other 6s had 3 shaded, maybe Tigo on the full sun 6s could boost current even higher, lowering voltage to match the other string's 3 panels in sun. But I'm not sure.

 

[rfsam]

Shade on a panel when others in string have full sun forces full current through it, may cause failure. Best if this only occurs when sun is off angle.

That's pretty much a condition I have...

If you had 6s in full sun and other 6s had 3 shaded, maybe Tigo on the full sun 6s could boost current even higher, lowering voltage to match the other string's 3 panels in sun. But I'm not sure.

Yep, that would be ideal... I probably need to call Tigo and ask that question.

 

[Hedges]

KISS:

Plan your shade wisely.

 

[DIYPV]

Only if the MPPT is too stupid to try drawing more current, causing voltage to drop until bypass diode is activated.
If it is smart enough, you still get 9/10 panels producing, 90% power.

I’m having issues with my 10S string and can’t figure out if the bypass diodes are not functioning or if the MPPT is as you mentioned “too stupid” to allow bypass diode to be activated..

Assuming the panels had only 1 bypass diode, is the above as @Hedges explained correct?

https://diysolarforum.com/threads/d...-partial-shading-situations.59840/post-766839

 

[AZ Solar Junkie]

All this math is giving me a headache. I'm just going to cut that damn tree down when my wife is gone to Walmart.

I transplanted a small palm tree while my wife was gone at a Bible study group. . Improved my array quite a bit.