Adding more PV

[russ_fae_fyvie]

Me again !

Now that the cost of PV is coming down, well even compared to when we installed the originals 2 years ago, I am thinking of adding to the system.

First of all the original setup is wired to a SB1700 (1.44kw array) and then into the MCB of the house. it was MCS approved so we get FITS. If we weren't bothered about FITS and wanted to simply add another 8 panels that our local sparky could install (possibly on the ground instead of the roof to save cost) would it be possible to tie it into the house without going through the SB1700 (I assume we'd need another inverter). Anyone who has done this Id be interested to hear your thoughts.

I'm assuming we could get basically a copy of what we have now, wired into the MCB ?

Would we also need to increase the battery bank ?

[defiler]

If you're grid-tied, you'll obviously need a second inverter, and the output from that will have to bypass your generation meter.  So to answer your first question, "yes", though you wouldn't need the generation meter unless it was being put forward for FiTs (you'd probably want it anyway, but that's another matter).

As for the batteries, I have no idea how you're wired up there, so I'll sidestep that neatly thank you!

[billi]

Hi Russ

What is  your battery size again ?  As well i think the Sunny Island you have, has about 2500 max   charging capacity ,  

So if you go the AC coupling route  again,  not all of the  PV might be  absorbed  from the Sunny Island to charge the Battery , when your use in the house  is low

But perhaps you can shift power to AC consumers via a relay   when 2500 Watt PV  performance exceeds ??

But this depends  on your PV size   you have in mind

I would say you are better off with a chargecontroller , but  again ,  it all has to work safe  with your dump load controller of the turbine

Billi  

[russ_fae_fyvie]

Hi bill
Took me a while to dig out the info !
The Batteries we have are Rolls S-530  (525Ah, 24v, 12x2v cell configuration) just read off the invoice !

[billi]

I only find  Rolls S-530  as a 6 volt Battery   and the capacity is  about 400 ah   in a 20 hour discharge time (C20)  so i assume you have 4 of those in series   to built a 24 volt battery  of 400 ah @24 Volt   C20


To be honest , that is quite small 

[russ_fae_fyvie]

It is these little devils !


http://www.rolls-battery.com/pdf/pdf_rolls/s530.pdf

Haven't a clue how they are wired together !!

Sorry

[billi]

Yes the same  as i linked the illustration  ......   are there 4 or 8 pieces ?   I hope 8 but think you have only four of those 6 volt batteries

But then your invoice  or better have a look at the estimate    is miss leading cause they talk of 2 colt cells

The Batteries we have are Rolls S-530  (525Ah, 24v, 12x2v cell configuration) just read off the invoice !

If you have a 400 ah  C20  Battery  i would say its not advisable to have more than 80 AMP charge   and your 1440 watt pv with your Futurenergy windturbine  should be enough for that size Battery   ( if i am right with your Battery size)

Sure you can perhaps  just get more PV and limit the charging Amps  in your Sunny Island   and/or  in the charge controller of your new PV

But on the long run i think that battery is too small  for a family home

[russ_fae_fyvie]

billi, there are a total of 8 batteries.

Unfortunately this is another area I need to learn before we look at any possible upgrades, only thinking about it at the moment !

[billi]

Russ

 8 Rolls batteries  sound much better   

so  i would see no problem to ad  more PV ....

And perhaps think of ideas how to use the  "overproduction"