Most of this install I can attribute to Handybob http://handybobsolar.wordpress.com/t...ging-puzzle-2/ [re-post]
It was not my intention to blatantly copy his system downspec'ed until I tried to find a better or similar one where none could be had as far as I could tell...and I've been looking for a month.
If you can make it to the end of that link I recommend the rest of the blog, particularly his meter rants.
I've been gauging my battery condition subconsciously for years and I have gotten rather good at estimating a state of charge, despite having two conflicting voltmeters.
After watching the voltmeter today running the module for the first time I'm glad I ordered the Trimetric. It's one thing to estimate the actual voltage while there's a load on the batteries. It's an entirely different story trying to do it when there's a load and a low current generator at the same time.
I also owe thanks to PaddyP for straightening my expectations out with his indispensable formula,
indispensable because after one month looking I have yet to find a site that makes the same comprehensive list of hidden losses.
Total annual solar insolation ireland - 900-1200 kwh/m2
100w panel = approx 0.5m2
450 - 600k kwh total to be captured
Panel efficiency 12-14% say 14%
63 - 80kwh per year
Lead acid charging efficiency 70%
44kwh - 56kwh = 10 - 12.8Ah per day annual average.
May/June/July Dublin 5kwh/m2/day
5 x .5 x .14 x .7 = 0.245kwh
245watts / 12 volts = 20.5Ah per day summer average.
Also there's high temperature inefficiencies to be considered (abroad) and I'm looking at a 40% output reduction for mounting the module flat.
Being the optimist that I am I up-spec'ed the module and cracked on. I'm going to install a shunt driven ammeter later so hopefully in a few weeks I can get back with some numbers.
I'm intending to retrofit adjustable tilting brackets (tiltable both sides) eventually but I daresay it'll be rare I use them as I don't often stay put very long so not a priority. In this case I think it's more practical to get 40% more panels to offset the loss.
Also on the long-finger agenda is a wind deflector because perhaps the best solution for too much ballast on the roof is more ballast on the roof.