mismatched arrays

[classicaussie]

Hi all from aus.
Been off the grid down here for 14 years now & looking at some upgrades
Just curious for some thoughts from the experts

I have just got a new classic 150 & looking to replace the 2 pwm controllers that feed from 2 arrays.
Problem is the 2 arrays are different types of panels & im curious as to thoughts on whats  best how to hook them all up.

Batt system is 24V 1100Ah
Trace sw3024 inverter/charger.

array 1:
16 x 12v BP solar 80W
Voc 19.5
vmp 17
Imp 4.5 -  configured for 24v (8 x 24v)

Regularly get 40amps from here & have measured voc at 40V (2x 12v in series)

array2:
3 x 200W tianen (yep chinese) 24V panels
Voc 45V
vmp 40
imp is 7 amps so im told

Have had up to 20amps from this lot at times & measured voc at 43.5.

Looking at a couple of configurations without the need for another classic.....

1. is it best to just hook them in parallel as is & the voltage of both isn't so different (43.5 & 40V)? Gain over pwm would still be ok id imagine.

2. or should i do something like 4 x 12v (approx 80V)  in 4 strings & 2 strings of 2 of the 24v (buy another one & its approx 86v)? Gain would be better than in point 1 right?

Has anyone done similar?

appreciate your thoughts
cheers
Mark

[dgd]

Second option. Use V max power in calculating working voltages as Voc doesn't matter unless they add up to near the Classics max voltage limit.
So 4 by 17v (I seem to remember my BP 80W multi-xtal pvs were 17.2 or 17.4V)  is about 70v and those 200W pvs with Voc 44 probably have 35 to 37v Vmp so a pair would be near(ish) 70v.  The Classic will easily sort out the MPP  voltage for these combined strings and there is a nice voltage headroom between PV input and Batt V to get efficient MPPT and get some power in lower light conditions.
4 * 200W plus 16 * 80W  is just over 2Kw, well within what a single C150 can handle with 24V battery bank.
It it were me I would buy 3 more 200W PVs and get the total to near 2.5Kw 


dgd

[classicaussie]

Thanks dgd
Was leaning towards that way of thinking.

Yes you are right re vmp
on the 80 w label its 17. 68v =70ish
On the 200's it 37. 74v = 70ish+
6v diff +- other variables i guess is ok...

Might even do that recommendation of yours for 3 200s as well.

Otherwise happy with the rest. trace humming nicely & also have 1.2kw turbine.
Had my eye on the classic for a while now.

All the best
Mt