niel wrote: »
65w of pv will work ok (not within good charge range percentages) with an 85ah battery, but if you increase the battery capacity to about 220ah, there's no way you'd have enough current to properly charge the battery. the number of pv watts will need increased. you could roughly figure about a watt of pv for each ah of battery capacity at 12v and mind you that this is not a rule of thumb to go by in all cases as i'm only saying this as a rough idea for you. there isn't any good substitute for actual calculations. the general rule of thumb for most standard lead acid batteries, especially generic brands, would be a charge rate of about 5-13% of the total amp-hour battery rating based on about a 20hr rate unless the manufacturer would state otherwise. do know that many can take the higher rates, but even with that ok from the manufacturer, the farther it is above the 13% rate the higher the maintenance will be and a possible increased chance of failure for some more cheaply made batteries.
BB. wrote: »
The Wattsup and such list Watt*Hours--and you just need to do the division by battery capacity with a calculator.
niel wrote: »
very interesting mike, but looks very heavy. any chance of that rim casting a small shadow?
OK, I finally got a public pictorial up about my Monolith construction.http://tinyurl.com/SolarMonolithConst
mike90045 wrote: »
Sure there is a chance, but re-aiming 3 or 4 times a day solves most of that. And 1 or 2x day bath in the desert to keep the dust off. Many folks without a water allotment for panel washing, get very low power by the end of the 2nd week.maybe hand wash as best as you can and then use a 12v portable sweeper for finer stubborn particles.
And, heavy is the idea, when I pull the dolly off, it's much more resistant to walking away. Two people can carry it a short distance, but not far. Also resists wind gusts pretty well. (2 batteries make great ballast, they are in marine battery cases, with the straps lashed on)good points.