Showing posts with label carbon. Show all posts
Showing posts with label carbon. Show all posts

Friday, July 5, 2013

Different way to have battery backup on gridtie

This idea came directly from my previous post on a practical PV backup system. I have some grid tied modules nearby my battery backup shed and wanted to employ the grid tied modules to help out when the power was down. I decided to switch 6 modules into a 2 x 3 panel series string to feed the charge controller. The above diagram represents one string. It will deliver >100 VDC @ ~8A. My charge controller, an Outback FM80, can take in up to 150 VDC.
By using 120 VAC for the relay coils, it will automatically switch to DC mode if the grid goes down or you turn off the supply switch. Care should be taken switching in full sun/load conditions. It could shorten the life of the contacts in the relays. Disconnect the AC and DC sides of the system when practical.  You could install 4 RC snubbers on each relay or buy solid state relays. Either is kinda expensive. There may be no problem at all.
I'll be installing this over the next few days and I'll let you know how it works, or not...

Thursday, June 10, 2010

Nothing remains the same




Usually, I would focus on the positive but, this time I must reveal a personal, somewhat unsettling discovery.
Its about mushrooms, or at least the ones in a jar I love to put on my pizzas. When I was either an elementary student or a Cub Scout, I was on a field trip to Temple, PA, the mushroom capital of the world. It is located near Reading, PA in Berks County. I remember countless huge long barn-like structures without windows. Inside were continuous racks, like bunkbeds, full of manure and thousands of button mushrooms.I have images stored clear as day still and always think of that experience when I buy mushrooms.
So, the other night I was making a couple small pizzas for dinner. I looked at the jar while waiting on something and saw the Pennsylvania Dutchman logo and "Americas favorite mushroom" (which is bordered by the outline of the USA) on the front label. I turned the jar around and saw the funny little caricature of a PA Dutchman. Near the bottom I saw Giorgio Foods of Temple, PA. My mind flashed back to the experience of my youth and felt satisfied.
My eyes swung to the bottom of the label and I was shocked beyond belief; it read PRODUCT OF CHINA. After a moment I thought about how I was mislead by the jar. Then becoming calm again, I wondered how the "Capital of Mushrooms" would outsource their product and ship it in from halfway around the world. Gosh, I wondered if there are traces of heavy metals and who knows what in that jar. Plus, think of the energy required and carbon released to maintain this method. The money would be better spent paying higher wages to the local industry and continue to recycle manure into wonderful mushrooms.
The point of this message is that not all is what it appears or what you used to know. I already spend at least half my time in the market reading labels trying to avoid certain things in the ingredients. Now, it looks like I'll have to ramp up my vigilance while shopping. Great....