I second Mike's suggestion for sunglasses on startup. Wait, ........better go for welding helmets. Those DC arcs are bright. And I bet they didn't use listed electrical tape either! :-) Thanks for sharing this one.
Dick Ratico Solarwind Electric --- You wrote: Typically those types of modules are rated for 30V. Most 12v amorphous modules under 40 watts are rated for that. I would recommend sunglasses for startup. Mike m...@powerupco.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jeff Yago Sent: Tuesday, April 27, 2010 9:04 AM To: RE-wrenches Subject: Re: [RE-wrenches] low voltage modules in high voltage applications First let me say that we almost never work on failed systems, especially when its for somebody that picked our brains on pretense of buying a system, then they went out and bought everything on the internet, and when nothing worked they call us! Also, let me say that the following project has nothing to do with us other than a call from an electrician who is installing a grid-tie system for somebody I don't know who had a few general install questions and was hoping I would provide some guidance. My advice was to run as fast as he can! Here is the story- This commercial building owner went to Harbor Freight and purchased a trailer truck load of 12 watt battery charging modules. You know the ones you see advertised to trickle charge a car or boat battery. I have not actually seen the modules this guy purchased, but based on others I have seen they typically have a potted junction on the back with 3 feet of very limited insulation wire pair out with bare wire ends. A few more questions and answers indicated these were made in China, had no label listing their ratings except indicating 12 watt at 14 volts. The very large physical dimensions he gave for such a small wattage tells me they are those thin frame amorphous you see being sold to keep your truck or tractor battery charged. To make a long story short, this electrician said they had already mounted "hundreds" of these modules on the roof of a warehouse, and were wiring them in series for connection to a Fronius grid-tie inverter. Also, he said the wires from each module was routed through a separate hole in the roof and then tied together. I assume this was by the ol ball of electrical tape wiring method. Not counting the obvious code related problems with what they are doing, and the almost sure need to have a fire truck nearby when they start this thing up, does anybody know what a typical high voltage rating would be for this type of module and the small wire pair? My guess is the small wire and/or the modules will quickly break down and start arcing, then the entire array will melt down which is what I told this electrician could happen. However, since there is no label on the module, I am only going on gut feeling as to the voltage rating of these cheap modules which I am sure were clearly never designed for series wiring to achieve high voltage. Anybody know these ratings? Should I sell tickets for the fireworks show? Thanks, Jeff Yago --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
