I purchased an AJ solar 540W panel from Rubicon in December. Cost R5 800 for cable, fasteners, connectors and panel.
I've got an off grid circuit that supplies all essential electrical items with my Mecer 1.2kw trolley. The battery is fully charged at about 1pm from the panel, and discharges to about 20% overnight, so it works pretty well.
I also have a Mecer 1kW trolley. I have the same issue of the maximum battery charge going down by 1% every day. This morning I decided to discharge the battery completely. At 7:30am the display said 0%, but it continued to run for another hour and 15 minutes! I have recharged the battery, and the display now says 100%.
This means that only the reading on the inverter becomes more inaccurate as time goes by. I don't think that this is a big problem, as from time to time I will just discharge until the battery goes flat. I'd rather do this than have some technician get hold of it, and maybe he doesn't know what he is doing.
I got a Mecer 1kw trolley in December last year. In the last week or so, it has been dropping 1% per day, and today it was 2%. I wonder how low it's going to go.