Hi Random, You will fit in well here I think. I don't consider myself to be an expert, but here are my thoughts on your remote power plans;
Set a goal and work your way towards it. That is what my father told me, I think it was a quote from some famous person long time ago.
It applies to your situation in that you need to figure out where you want to end up, and then piece together the equipment to get there such that it will be useful in the finished system.
Most successful remote applications that I have visited seem to have one big thing in common, --redundancy Usually at least three sources of power to their batteries, Solar, Wind, and a diesel for backup for example. If you are lucky and have a water source, that works too. The sun will not always shine, and the wind will not always blow, but often when one is not producing the other will, think of those windy dark winter days, or those calm sunny ones. If neither of those are generating or one is broken, then a good diesel backup is great to have.
The batteries will be the heart of your system. That is where the power you generate will be stored. The reason that you see the amp rating on the label of the batteries is that they apparently double as starting batteries. Starting batteries usually have more surface area on the plates for amps, but thinner plates. Generally for true deep cycle storage batteries, you will not see a CCA rating because they are not designed for starting and the ratio of amps drawn to amphours stored will be much smaller. Also, for virtually all battery chemistry types, the deeper you cycle it the fewer cycles you get from the battery. I read from one manufacturer that in order to draw the most power from the batteries over time, for that particular battery, the bank should be sized for a 20% depth of discharge. That means that if you wanted to use 20 amp hours from when the batteries were fully charged, ideally you would need a one hundred amp hour bank. Batteries cost money to initially buy, so most of the sites I have seen have battery banks that get discharged a little deeper even during normal use. 10.4 volts is pretty near completely discharged. Although as was pointed out above in another response, with the voltage drop in the wiring and the amp load, the actual battery voltage was likely a bit higher on your batteries.
You should read over the excellent battery fact page that the hosts here put together. It is located here:
http://www.otherpower.com/otherpower_battery.html
If you haven't already, you will probably find it interesting to check out the wind and solar especially, but probably all of the links on the bottom of the front page at www.otherpower.com
One of the first choices you will have to make is what voltage you will wish to operate your system at. Take a look at DANB's system closeley. He is running a remote house and a shop, much as you wish to do. He originally had a 12V system and eventually switched to 48V because of the ability to move much more power in much thinner wire, and with smaller diodes and heat sinks, ect. If you were using just 2500 watts in your shop, at 12V that would mean moving at least 208 amps from your batteries to your inverter, plus any inefficiencies. Since you will want to keep those batteries charged, that probably means some pretty good amps into them from your sources at times as well. If your peak draw with your tools is 4000 watts, well, think of the cable size and and runs you will need to connect everything, the diodes, heatsinks, number of diversion controllers, ect to handle the amps on the generation and dumping sides of it as well. I am not sure of the longterm life of that Chicago inverter, even though it is named after my home town, I suspect it was not made for continuous heavy duty use. I could be wrong on that, but I suspect you will want a proven heavy duty inverter anyway, like a Trace or Outback inverter ultimately. My thinking is that you should look at the operating voltage, make a decision on where you want to end up, and head in that direction.
You have the option of buying new batteries and rigging sets of 4 in parallel and then rewiring to 48V later on. The same is true of solar panels, and with some solar panel charge controllers, like the Trace/Xantrex C40 which I have and have knowlege of, you can change the voltage for them by switching a jumper inside. I have one that I used on 12V in the past and switched it to a charge control mode at 48V. That way, for now, you can operate your panels and batteries with your current inverter on 12V for now, and when you inverter kicks the bucket, or if you decide to upgrade it, you can switch to 48V relatively easy.
Because I think the solar panels are generally simpler to install and easier to keep operational I would probably start my renewable energy with them. I have some eva encapsulated panels of the type that typically come with a 25 year warranty, that are probably 25 years old, and generally still work fine. I figure that unless someone breaks them or steals them, I may never have to mess with them. I would not be so certain of the ones with a front face of epoxy or the amourphous designs that one typically sees with a shorter or no warranty.
I suspect you will want wind as well, so once you get going with this you will have to figure out what type of turbine is for you. As for wind, changing between 12 and 48 volts will depend on what turbine you have. If you ultimately build a dual rotor axial flux machine, all you would have to do is make a new cast stator, the rest of the mill would remain unchanged. If you have a motor conversion, you would have to rewind the stator as well, although I have seen a few where more winding connections were ran out from the stator so that the voltage could be switched. Zubbly would be an expert here on that. With careful design, you could accomplish the same thing with an axial type machine as well. Assuming the voltage rating on the rectifiers is high enough, you could use the same setup. In general with this setup, if you have something like the C-40 charge controller, you would connect the output of the turbine through the rectifiers to the battery bank, and use the C-40 as a diversion load controller to turn on a dump load when the voltage of the batteries climbs too high. Actually, you might ultimately need more than one if your generating capacity is such that in high wind and sun it can be sustained in excess of 40 amps. (actually, you won't want to connect a dump load at 40 amps to it, I should run and check, but I believe the rating is less in that mode, and I recall a post where someone smoked one at 40 amps and was wondering why. I bet someone reading this will know the answer off the top of their head.)
If you do ultimately switch to 48V, then you can still use your 12V stuff if you get a dc/dc converter. You might be tempted to connect them across a 12 volt section of your 48V string, but don't do it because it will likely ultimately lead to over charging part of your bank and prematurely ruining some of your batteries. For example, I picked up a couple of approximately 12.5 amp at 12v, 48V to 12V converters off of Ebay for about $15 in the past.
Welcome aboard, Random, Rich Hagen
