This such a timely thread. Too bad I made the same mistake. I just put on a real neat 40 watt panel on the bimini top of mt Beneteau 331. While i waa installing and mounting i went from 12.3 to 12.6 in few hours on a sunny day. Im on a mooring. My daughter went down last night after 3 full sunny days. She called and said it was at 12.6! Not the 12.8-12.9 i was hoping for.FourPoints said:I had the same exact sunforce controller when I hooked up my panel this spring, My batteries were a little over 50% charged (reading right around 12-12.2v) when I installed everything, and after 3 weeks of good sun with little to no load on them, I found that the batteries were still only testing around 75% charged according to the hydrometer. That is when I started digging into the differences in how the charge controllers worked and found that the sunforce was actually preventing the batteries from fully charging by turning off as soon as the surface charge reached 14.2v, and never allowing much charge to be absorbed. The self discharge of the batteries was almost equal to what I was actually inputting through the sunforce controller, and in the end I wasn't really charging much of anything.
I went with the Genasun GV-4 (http://www.genasun.com/gv-4.shtml) on Maine Sail's reccomendation (I beleive he actually has a genasun, not a morningstar on his boat), partly because I don't have enough room to install a large panel so I needed to get all the juice I could out of what I have (12w), and the MPPT gives me a nice boost in the mornings.
I checked on everything a couple days after hooking it up, and found the batteries were sitting at float stage and the hydrometer was indicating full charge. Every time I have checked the batteries since installing the GV-4, they are sitting at float stage and fully charged within a day or two of getting back at the docks from going out for the weekend, and no matter what I seem to do power wise at the dock they are always recharged the next day (and no, I don't have a shore power chargeing system).
In short, the sunforce is half worthless and get rid of it, replace it with a good controller and you will be very happy with the decision.
I also have the 7 amp sunforce. Just bought from west marine.
Question: could it be also a bad battery? Or it seems clear the sunforce controller may be a poor choice?