Kaneka GSA? [RE-wrenches]

[Bill Brooks]

Travis,

I think you might have misunderstood my post. Littlefuse makes a KLKD-3.5
amp 600Vdc fuse that will definitely work on this module for two sets in
parallel. Given the more specific specs that were provided, it appears that
a 3-amp or 3.5-amp fuse will work. Both are available.

The size of the system dictates how many fuses you will need. There are
4,6,10,12,20,26,and 52 string options for combiner boxes. Make sure you size
your system so that you can take advantage of Square D's ratings for single
pole in their 3-pole disconnects.

30-amp--18 amps per pole
60-amp--60 amps per pole
100-amp--100 amps per pole

It is all doable, but you make a good point on the practicality and cost
side of things. A-Si modules have to cost at least 25% less than crystalline
to even start the discussion (maybe cheaper than that).

Bill.


-----Original Message-----
From: Travis Creswell, Ozark Solar [mailto:ozsolar at ipa.net] 
Sent: Monday, August 21, 2006 8:14 AM
To: RE-wrenches at topica.com
Subject: RE: Kaneka GSA? [RE-wrenches]



Thanks for all dialogue about these modules.  I really appreciate it.  I'm
learning a lot.

Let's see if I'm getting this so far.

There is not an appropriate sized fuse available so you can't parallel the
modules without a combiner box.  SMA's website says the Combi-Switch can do
4 strings.  Assuming your local climate will allow 5 in series that's 300
watts per string x 4 strings for a total of 1200 watts.  If the inverter
allows two inputs you could use two Combi-Switches and double that. Now
you've got over $1k retail just in Combi-Switches for 2.4 kW system.  I see
they also have Sunny Central Combiner boxes but with that product won't you
need a disco in between the combiner box and the inverter (some string
inverters have one built in).  Any ideas what a 20 string Sunny Central
Combiner costs?  What size of fuse is required in the combiner box if you
aren't paralleling?  There seems to be some disagreement on the actual
rating of the module.

After one buys some sort of combiner and does the extra labor to fiddle with
all the strings the Kaneka's lower price per watt likely loose their
attractiveness for grid tied systems.  Since they are thin film type product
your racking cost is going to be approximately double.  ~2x the ft2 required
for the same wattage array as crystalline. 

For less then 150vdc systems there is a solution.  But there is still a fair
amount of labor involved to get to a sizeable array.

Thanks,

Travis Creswell


-----Original Message-----
From: Jeffery Wolfe, Global Resource Options
[mailto:jeff at globalresourceoptions.com] 
Sent: Monday, August 21, 2006 6:09 AM
To: RE-wrenches at topica.com
Cc: Travis Creswell, Ozark Solar
Subject: RE: Kaneka GSA? [RE-wrenches]


We worked with Outback awhile ago to get some 3A circuit breakers for their
stuff for use with Kaneka. They now have them, 150VDC, 100% rated. So if
you're using Kaneka with batteries (lots of wiring) you can string in 2
parallel strings at least though one CB. No similar solution for the higher
voltage of grid-tied.

Jeff

Jeffery D. Wolfe, P.E.
Global Resource Options, Inc., Solar Energy Solutions -----Original
Message-----
From: Bill Brooks [mailto:bill at brooksolar.com] 
Sent: Wednesday, August 16, 2006 5:04 PM
To: RE-wrenches at topica.com
Cc: 'Travis Creswell, Ozark Solar'
Subject: RE: Kaneka GSA? [RE-wrenches]


So Matt,

What would the appropriate fuse rating be for two series strings in
parallel? 

Assuming the Isc is 1 amp, then Imax = 1 amp x 1.25 = 1.25 amp [690.8(A)].

Therefore you must subtract the 1.25 amps from the 5 amp rating so the max
fuse rating is 3.75 amps

Two strings in parallel have a max current of 2.5 amps (1.25 x 2), and the
minimum series fuse rating is 2.5 amps x 1.25 = 3.1 amps [690.8(B)]. So the
correct number is 3.5 amps.

The only fuse allowable for this arrangement of two strings in parallel is a
3.5 amp fuse. I'd be interested to see if they have this in their
literature.

Bill.


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