Conversely a panel with low FF due primarily to low parallel resistance can in fact be
advantaged. I must point out here that we have only seen a few panels like this at
scrutineering for power testing. I do have such a panel in my possession, its test results
are included in the table below.
Examination of the table below will hopefully clarify this for you. The table shows light
box test results of panel test, the column ‘Ballast With No Panel Power’ shows the
ballast weight carried (calculated from the 2010 formula) for which there is no actual
power produced by the panel. This is because ballast is calculated on power taken at 50%
Sun and doubled.
PANEL POWER WATTS FILL FACTOR BALLAST WITH COMMENTS
100% Sun 2 x 50% Sun NO PANEL POWER
9.14 10.20 0.65 212
10.20 10.16 0.71 8
8.20 8.64 0.59 88
10.56 10.56 0.75 0 Victorian master
9.62 9.44 0.76 36
9.81 8.62 0.57 minus 238 ie. an advantage
11.19 11.38 0.76 38
Clearly whilst panels with a high fill factor always perform well it is possible for a panel
with a low fill factor to perform even better from the ballast point of view. The secret is
in the panel characteristics namely the split between series and parallel resistance of the
panel. Who would want to use a panel with the characteristics of the first panel shown in
this table? However the panel second from the bottom would be great.
The regulations have been changed for 2011 to reduce the effect of the anomaly shown
above. The change made is to measure panel power at a Sun level nearer to that expected
to prevail during the course of racing, then ratio up to expected power at 100% and use
that value for ballasting purposes. This means we will hopefully be conducting our ratio
over a narrower band with resulting lower errors.
APPENDIX G