The 250w panels are 165cm x 99cm 1.6335m^2 so efficiency at 1000watts per m^2 is 15.3% (250 divided by 1634)
I am a bit put out by the physical size and have thought I probably only needed one not 4 ??
Initially I set up a single panel to charge one of the old batteries via the Steca Controller which showed some 8amp of charge, burning of all voltage above 14.7
Now the panel is connected via a Victron MPPT to one of the new Rolls batteries; with no charge readout but in theory providing a max of 20A to the battery.
For more on charging the rolls
Emails about damage to corners
1.To Wind and Sun
I called today to query the crimping inside each of the corners, image attached; it looks like they have been installed somewhere previously??
Each corner on all four panels have the same damage.
2. To REC
Dear REC people
I recently bought panels from Wind and Sun UK http://www.windandsun.co.uk/products/Solar-PV-Panels/REC-Solar-PV-Panels#6160
Every panel has damaged framing on the inside of each corner. The distributor noted, upon checking their stock, that all the remainder had the same indentations and were keen to confirm they were not second hand and under a full guarantee.
However I am still uncomfortable that such indentations to the frame have occurred and wonder if you would explain how this has occurred.
Please see image attached, as noted each corner of each panel has been crimped as though they have been fitted to some other framework very forcefully.
4th Jan 2015
I have finally heard from REC but not before another concern has arisen. There is a gap between the frame and glass panel, which allows water in which will freeze and expand further widening the gap each instance.
A couple of images to illustrate the gap
Comment 3 REC's initial response and my reply.
Comment 4 REC's brain-dead response and my reply.