Series or Parallel

[paul.straker11]

Morning,
I am new to this site and starting my first PV project: to make my pool off grid with solar. I have got 10, 230 w panels with Vmpp of 26.6 and Voc of 37.4 ( apparently near 40v when hot). My hybrid 5 kw inverter max Voc of 500 and an input range of 120 - 450v.
is there any advantages in wiring either: 5s2p or 10 in series.
Thanks in advance.
Paul

 

[Barx]

How many trackers does the inverter (MPPT's) have? and what is the current ratings for the inverter?

 

[binky]

I would always use both MPPT trackers, assuming you have 2.

 

[paul.straker11]

How many trackers does the inverter (MPPT's) have? and what is the current ratings for the inverter?

Thanks for replying.
It hasn't arrived yet, the pv power rating is 6kw, there is no mention of dual/ multi tracking MPPT, and looking at the terminals I think it is just one.

 

[paul.straker11]

Sorry
the Current rating of the inverter pv input is 18 amps. the panels max at 7.8A

 

[Barx]

With the figure given so far, tecnically you could do either. I assuming you do realise the inverter of 5kW is quite a bit over sized for you array (10 x 230w = 2.3kW)?
Personally I would wire them all in series to get the voltage up as quick as in the morning and get the MPPT to kick in. If you were to do 2 parallels strings of 5 the array Voc would only be 187, which isn't massively over the kicking voltage of 120V

 

[paul.straker11]

Many thanks, I'll do series. Might be able to squeeze an 11th panel on the roof.
I went OTT with the inverter because I was concerned with the start load of the heat pump.

 

[paul.straker11]

My inverter arrived, and testing started today!
4 x 200 ah batteries full and moderately sunny day for the 10, 235w panels

My GSHO and circulation pump ran for 4 1/2 hours before the system did a low V shut down ( grid connection isolated for the duration of the test).
So theoretical consumption was 14 Kw/h . Say 8 from the batteries and 6 from the array. the pool temperature was raised 2 degrees C, enough to maintain its 34 C my wife requires. ( its only 3 x 6 x 2 m deep ( with a swim pump)).
the easterly facing array did well. Unfortunately with a 2:45 shut down there wasn't enough pv to fully charge the batteries for tomorrow. We got to about 70%. the test started a little late so !'m hoping a 1pm finish will suffice! i am under no illusion that both the array and the storage will need expanding for later in the year! All in all a satisfying outcome.

I had a small issue:
Before starting the test I got a shock from a pv panel frame. Most confused I got to work with a test meter. 70 v ac between the frame and earth. I added the grid connection ( switched off), to bolster the earth .......no change. Current was a few mA. I isolated the workshop supply to exclude induction or remote leakage......no improvement!! I isolated the panels from the inverter........... problem gone! So I bonded the frames to earth. no more shock. Any thoughts??