How big of a solar system is enough?
While planning out the addition of solar to my 2009 Lance 1880, I gravitated to the 160 watt systems right off the bat. It's what the new trailers come with and seems to be a common wattage available....
Forum Discussion
1stgenfarmboy wrote:It doesn't take much to charge a couple of nicad D cells. ;)
I just talked to our friends who are full time in a 26ft TT, he said they can run there 2 batteries almost down and the 160w system will have them topped off in 2 hours in the southern CA sun, 6 hours on a cloudy day.
In a real system, 2 deep cycle lead-acid batteries would be in the 150-230 Ah range. Let's say 200 Ah. Recommended draw down is no more than 50% for good battery life. So, the need is about 100 Ah of charging after a "full" discharge. Ignoring charging system inefficiencies and the need to put more back in than you take out, 160W will provide a charging voltage of 14.4 V @ ~11 A, in peak sun. So it would take over 9 hours (9 hours x 11 A ~= 100 Ah) of directly overhead, noontime sun to recharge them. And actually much more than that, since the current tapers off as the battery gets full. It's hard to fully recharge a battery which has been drawn down by 50% in 12 hours, even with unlimited power available.
Either they're not discharging as much as they say, or their battery isn't getting fully charged. Probably a combo of both.
