Check your math. 20A times 12V is 240W. Throw in the fact that 12V batteries charge at voltages above 14V makes it 280W. So a 48V 200Ah bank should be getting 20A times 56V or 1120W before charger losses. This set up could recharge a 60% discharge in about one full day of sun.
Since a 200W panel is about 15 sq ft (5' x 3', 40 lbs), if you've got a 48V system, three panels (5' x 9', 600W, 120 lbs) will produce close to 10A of charging during peak periods. This setup would recover a 30% discharge each day, a little less in northern states.
Back to my original quote, a 250-300W (5A) solar array will replace about 15% of a 48V 200Ah (9600Wh) battery per day, and will take 4 days to replace a 60% DoD, not including live loads.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "sirdarnell" <sirdarnell@...> wrote:
>
> No, slow charging will not reduce battery life, assuming you are recharging completely before using....
>
> Using solar panels to charge at 0.10, i.e. 20A, at 12VDC would require 120 watt "12 volt" panel. 48VDC would require 4 120 watt 12 volt panels or 2 120 watt 24 volt panels wired in series. For faster charging you could us larger panels or a second series of panels in parallel Actually, the panels would need to be 10-15% higher to account for inefficiencies in the charger. Also, if the battery bank is used for some other purpose while charging you'd need enough extra capacity to handle the live load, as well as the charging load. An 80 amp charge rate would require 480 watt panels (which I don't thing anyone is currently making, large panels tend to be under 220- 250 watts.)
>
No comments:
Post a Comment