[RE-wrenches] not sure what's going on here

[Larry Crutcher, Starlight Solar Power Systems]

Hi Ron,

The problem you describe is due to the firmware in very early versions of the 3024i. What would happen is once you hit the 30 amp current limiter, the controller will switch the input to act like it is connected to a nominal 12 volt module, lowering the input voltage. Contact Blue Sky for the firmware upgrade to correct this.

Sincere warning: Although the Blue Sky product handles SOME overload very well, 660 Watts is severe for this 30 amp controller. You have the potential for over 50 amps of current. This can result in the controller becoming a fiery mass of charcoal. Seen it; don't like it. Make sure nothing is in the vicinity of the front panel when this happens.

Larry Crutcher






On May 10, 2013, at 4:33 PM, Ron @ earthRight Solar <solareagle at solareagle.com> wrote:

Hi Wrenches, 

Wondering if anyone can shed some light on this. I have a customer who self installed 4 x 165w Solarworld panels a few years ago (2008). It's a 12v nom. battery and the panels are wired in parallel. They've been working fine for five years on a full time household using a 3024i Blue Sky controller albeit driving it well beyond it's max PV power recommendation as currently published by Blue Sky. 

However, now one of the panels has dropped from approx. 30-35v output to 13v. When the failed panel is removed from the string the three remaining panels come back to normal voltage and amp output but after about 15 minutes drop down to around 13v on the Blue Sky display - even though the individual output from each panel when unhooked and tested in full sun show about 35v. After turning the system off and on again a few minutes later the normal voltages return but drop again in about 15 min. The failed panel stays at 13v, does not recover.

I'm trying to do a little pro bono diagnostic for the guy who lives back in the bush. I haven't been to the site but asked him to carefully check all the wiring and he says it's fine. So two questions. First- is there a diode in the failed Solarworld (sealed J box) that could have failed and if so is it repairable? Second, any ideas what could explain the intermittent drop in voltage output of the remaining three?

Ron Young