Help with my aged KC120-1 solar array

System · August 2007

My 24 panel KC120-1 solar array is 6 years old now and has not performed up to my expectations nor what I believe are the experiences of others.

Here is the current state of my solar array:

I have 24 KC120-1 panels.

The panels are in series in groups of 4. I.E. 48 volts per bank.

The panels that make up each bank are interconnected with 10 gauge wire.

Each bank of 4 is then routed via 10 gauge wire to an outback panel combiner.

From there 6 gauge wire leads to a C40 charge controller, and from there to a SW4048.

All of the wiring is inside sealed watertight conduit and fittings.

And here is the result after 6 years: http://home.worldcontrol.com/solar-output-20070812.html

The voltages are the open voltage from + to - on each panel, and the amperage is the amperage measured from + to - on each panel. Measured using the outer most screws.

The C40 measurements are via the C40 display panel. I turned off all the panels via the panel combiner breakers, then turned on one bank at a time and read the numbers from the C40 display panel.

Any thoughts on what might help this array produce better?

BB. · August 2007

Re: Help with my aged KC120-1 solar array

It is possible that your panels are part of a 2001 date code failure that Kyocera has been replacing (without much hassle) when people call them or the distributor... Check this Solar Guppy Thread for some details.

-Bill

Windsun · August 2007

Re: Help with my aged KC120-1 solar array

You apparently have a 4x6 array, with 4 panels in series x 6 panels in parallel.

#1. #10 wire is too small. You should have #8 as a minimum. #10 wire is only rated for 30 amps in free air (a little less in conduit), and you could be pushing up to 43 with that setup. And you are probably getting a fair voltage drop unless it is a very short run, even aside from the wires getting hot.

#2 What the previous poster said about some bad panels, contact Kyocera - you will need the serial numbers.

#3 The C40 is under rated for what you have. And you could also get over 60 amps out of those arrays with something like the Outback MX60.

Vic · August 2007

Re: Help with my aged KC120-1 solar array

Hi Snb ..

Just a couple of thoughts ...

1. Is this system Grid-tied, Off-Grid ?? Where is the PV power supposed to go ? During these measurments, what was the demand for PV power in excess of battery charging ? Selling to the grid ? AC loads on inverters ? So on ..

2. Assume that the second number for each of the panels is the Current, Isc, measured using a DMM on 10 Amp current scale ?

3. Wonder if you have a poor connection somewhere in bank 3 & 4.

4. What state C40 in when you took its ? If there is no demand for power in excess of that needed by your batteries, and the batteries are in Absorb, or Float, then you may only need the power shown on the C40 (which I am unfamiliar with--think 40 A PWM?). This system has been running 6 years, sorry for the lecture on that which you know.

5. Obviously, bank 6 does have some prob at the first panel in the table.

6. There does seem to be quite a large variation in the currents of each panel, more than I would guess, but have no experience with KC-120's, altho did not know that panels this large were available 6 years ago.

Some additional context would help ... where are you, type of system--Grid-tied etc, any panel shading at all, very humid (possibility of corrosion at connections) and so on.

Vic

Solar Guppy · August 2007

Re: Help with my aged KC120-1 solar array

6 years = 2001 , many many many failed KC120's from that vintage and the reports still comming in from systems

Your test shows you have massive failures on two strings and some failures on two more, this would point to bad panels for sure

Call Kyocera ( use the link to my site which has contact info if you need it )

Kyocera will replace the entire array, whether they have failed yet or not

BB. · August 2007

Re: Help with my aged KC120-1 solar array

Simplest test to check for bad panels... Disconnect each panel and check Voc (voltage open circuit) and Isc (current short circuit).

To check Isc, just set the DVM to 10 amps max scale and connect to the solar panel +/- leads. In full sun you should get rated current, or a bit more. If significantly less--you have a bad panel (less than 80% rated current in noon time sun, clear sky, clean panels--for sure a bad panel).

-Bill

System2 · August 2007

Re: Help with my aged KC120-1 solar array

Thanks for the info on the panel failures. Reading other threads on this subject my failure rate even matches that of others.

I will contact kyocera. Though I bought mine from Arizona wind & sun.

Is it preferred to contact kyocera directly?

Any particular number people a dialing?

System2 · August 2007

Re: Help with my aged KC120-1 solar array

I just talked with kyocera. All of my panels are from the bad time and
they are going to replace them.

System2 · August 2007

Re: Help with my aged KC120-1 solar array

By the way, I talked with Arizona Wind & Sun about my performance troubles about a year ago, and they did not mention "this" problem.

BB. · August 2007

Re: Help with my aged KC120-1 solar array

You should contact Wind-Sun directly to ask the question--they don't closely monitor this forum for direct business questions/issues and may miss your post.

-Bill

Solar Guppy · August 2007

Re: Help with my aged KC120-1 solar array

Glad your going to get the panels replace for free!

all solar panels are warranted by the manufacture NOT the re-seller

My site gets allot of hits on this issue as if you google on KC-120 failure, my forum comes up with the #1 hit ... :roll:

halfcrazy · August 2007

Re: Help with my aged KC120-1 solar array

Glad to here they stepped up seems like they have been very good about taking care of there customers. enjoy the full potential of the new array

Help with my aged KC120-1 solar array

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