>nice , but you have a lot of assumptions in these calculations. >My U-1 is kept full charge with my solar panel and the Flex charge 7 amp >model from west marine. >the electric motor is for NO wind conditions, there are those who like >to >sail and use motors as a last resort
I am not clear on what constitutes "a lot" in the example provided. The only assumptions I made in these calculations were battery size (largest practical) and current draw of an average electric trolling motor (an average of typical models at high speed setting). The rest of the data regarding panel output, daily or weekly totals, solar radiation gain by region, and efficiency loss is straight from the Unisolar USF-11 owner's manual. My real-world experience with both the USF-11 panel and the battery size in the example corroborate the sample calculations. The point is, a panel with a *maximum* output 0.62 amp-hours will always take somewhat *more* than one hour to replace 0.62 amperes consumed. If your trolling motor draws 10 amp-hours at a lower setting, and you use it for one hour, replacing the lost power with the panel in question would take more than 16 hours. Adjust the numbers to suit your combination of panel, motor, and battery. I too prefer sailing to motoring. Some of us sail in areas where the wind is not consistent, seas are large, there is no AC power available for battery charging, there is significant cloud cover for most of the year, or sail distances or durations where having more than a couple of hours of one-time auxiliary capacity is either desirable or requisite for safety. My motive for taking the time to write this was to share my direct experience, and to correct the possible misconception that the Unisolar panel would be sufficient to recover batteries deeply discharged by use of an electric trolling motor within a reasonable time frame, and without the use of an auxiliary AC charger. I also hoped to clarify relative battery capacities for the purpose of estimating the reasonable range obtainable with an electric motor. To reiterate, the Unisolar (or other small panels) are great at their intended purpose--namely *maintenance* charging, and as I stated before, both electric trolling motors and small solar panels have their proper application. I think it is wise to know in advance the capacities and limitations of such equipment. Scott M15 #478 'bebe' Pacific Seacraft Flicka (unnamed) _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
