the production of the Sunny Boy 5000 is is in the range of 10Kwh/day.22 230w Solarworld panels 2 strings of 11 tilt 18 degrees and a -22 degree facing SE. I am expecting between 17-21 Kwh per day. does the Sunny Island on grid limit this in some way?

Hello Apollo070,
The Sunny Island will only limit the SB production on an off-grid situation if all loads are met and the SB has been programmed to accept the frequency shift from the Si. Additionally the maximum Si output is 6.7kw it will easily handle the output of your SB5000US.
As for low production, E x I = P. The first thing to consider when production seems lower then our anticipated results is, of course the weather. We are still in early spring so our irradiance and daily insolation values are going to be less then optimal which will result in lower overall production. Add to this spring showers and seasonal cloudy skies these entire combined factors place a negative effect on overall production… But let’s say the weather is perfect, not a cloud in the sky, the suns position in the sky is high, however, our production still seems off the mark, what could be the source of the low output?
1. Shading on the array? Detrimental to overall production.
2. Combined inputs, are all strings balanced? They should be.
3. Combiner box fuse blown? Eliminates the output of that associated string.
4. DC-disconnect fuse blown? Eliminates the output of that associated string.
Verify all dc input voltages and amperage of each string prior to the inverter and inside the inverter (amperage should be the combined result of multiple strings). Once again always remember E x I = P.