Sunny Island Logic Madness
Hello! Installation details listed at the end and am prepared for all the criticism as to having chosen an AC coupled system for Off Gid but there you go. I have had this system for 5 years now and am now replacing the first set of batteries which were Rolls AGM 270 AH at 48 Volts. Not lasted as long as I would have wished so watched new battery charging very carefully. What I seem to have found is that the logic that SMA use to start a Full Charge or Equalisation seems nuts. So, anybody out there got experience which indicates my observations are wrong?
So Sunny Island is meant to do a Float, Boost, Full and Equalisation.
Voltages can be programmed for all 4.
Times can be programmed for all 3 that are not Float with return to Float at the end.
When state of charge drops to 70% Float ends and Boost starts.
Unless the Timer for Full or Equalisation is zero in which case Full or Equalisation starts.
So far, so good BUT
If timer for Full or Equalisation finds a Float is in progress when it ticks down to zero it waits just one 'tick' to see if Float ends. The tick is 2.4 (so one decimal day) long and then it resets.
If timer for Full or Equalisation finds Boost is in progress when it ticks down to zero it just resets.
So this seems to set an unrealistic set of conditions to start a Full or Equalisation charge so it just never happens.
I don't want my batteries to never have a full charge. I also don't want to overcharge them. So I want a regime of charging to say 90% daily and 100% once a week. How do I get SMA to do that?
Thanks in Advance, Mark
3KW of panels
Sunny Boy producing 220 V AC
6KW Sunny Island
500 AH , 24 cells at 2V
0 · Share on Twitter