Solar Electric System Sizing Calculator

[MountainDon]

This is one of the easiest to use alternate energy calculator/sizers I've run across. All calc's are done with the online interactive form. The only thing I didn't like about it is that it's setup for a 50% battery discharge rate and it's my own belief that batteries last longer if limited to max 25% discharges. But that's easy to compensate for.

http://shop.altenergystore.com/Calculators/OffGridCalculator.html#

Prices are good too. They precalculate the per watt cost on PV solar panels; Evergreen 170, 180 & 190 watts panels at $4.39 today is quite fair.

[glenn kangiser]

They probably do but 50% is pretty standard  -- then there are my batteries. :-/

Actually I work them hard but they are holding up remarkably well - especially since I raised the charge voltage to keep them higher -- .

A solar supplier at Page, AZ mentioned that to desulfate, 24 volt systems need to be at about 31 volts equalize for extended periods of time until they shake it loose - then they will improve.  I tried it and he was right.  My greatly improved.  I have 4 that are a year older than the other 8 - no problems noted - they came up to a similar charge.  Say for several hours or more then monthly.  Many times the dump load or inverter will kick the charge off before it has done any good if not properly set or made to work at that voltage.

[MountainDon]

They probably do but 50% is pretty standard  -- then there are my batteries. :-/

I advocate being kind to them, not discharging any deeper than 25%, but I have to admit the RV batteries get sucked down to under 50% more often than they should.    

And the last time the backup batteries at home had to earn their keep I sorely abused them.  :'(  Kept hoping the grid would come back to life or the clouds clear so I wouldn't have to drag out the generator.  :-/

[fourx]

I have had a good run from the last two sets of batteries- because I got rid of the fridge, which was maxing out the batteries all the time. Now, I have a small fridge in my office and store freezer bricks in it, then bring tham home and stick tham in the ice chest. Easy, and cheap.

[glenn kangiser]

When I'm bad, factory default settings on the inverters try to give you all the AC they can - it pulls them down to near 20 v before going off.  Only happens when I'm gone in the winter and haven't shut the pump off - but it happens.  Everything's fine so far though.

[MountainDon]

...freezer bricks in it, then bring tham home ...

Ahh! In some other post you'd mentioned no fridge, but an ice box in it's place. I wondered where you got the ice, wasn't it a bother, and did it work out economically? I never got around to asking, now I know.  

[MountainDon]

I've updated my working bookmarks on solar calculators. Some may be better than others. I used a bunch of them.

http://www.wagonmaker.com/script_calculator.html
http://store.altenergystore.com/calculators/off_grid_calculator/
http://www.bigfrogmountain.com/calculators.cfm
http://www.affordable-solar.com/index.php?file=c-off_grid
http://www.solarexpert.com/Pvload.html
http://www.me.utexas.edu/~me374s/javatop.html