Attention all Solar Guru's!

The amount of output from the solar panel is going to depend on the amount of sunlight actually reaching the panels and that is going to depend on the weather conditions and the angle of the panels relative to the sun.

i assume that you have the panels connected in parrallel, ie red-red, black-black.

In the middle of the day on a clear winters day you should be able to get the full rated output of a solar panel if the panel is facing the sun almost perfectly.

I think the first thing to test is the panels . Disconnect one of the panels from the CTEK and connect it directly to the battery (red to +ve, black to -ve), then measure the voltage and current (or the "watts" if you have a wattmeter). You should be getting around 12-14volts on the battery and up to 10 amps (though probably more like 7-8Amps) in the cable connecting the panel to the battery. If not then you need to do open circuit and short circuit tests on the panel.
Do the same with the other panel as well.
If the panels check out ok, you should get someone to test the ctek. I have read that they do strange things when connections are incorrect, but dont know much else about them.

Allan

Tim
You didn't buy the panels from Mr Shonky on ebay did you? Can't recall his name but there are quite a few posts about him selling solar panels with inflated ratings. Have seen posts on this in last few weeks.
This may explain why they are producing less than expected.

Quote "I had the solar panels in full sun today and connected up a "watt meter" and it showed that the panels were producing approx 20-40 watts each (ie 60-80 watts in total). Out of a possible 240w this seems quite low. Is this normal for a winters day?"

That is an unusual way to measure your panels. What is the details of the meter you were using and how was it connected? The usual way to check your panels is to connect an amp meter across their terminals and measure the short circuit current. (Its safe to short out solar panels, they don't produce enough power to blow anything.) You should get around 14 A or a little more (7 A each one) short circuit current with the panels aimed square on to the sun. I can't comment on the "60-80 watts in total" unless I know how the tests were made.

Quote "My other problem...the CTEK is continually turning itself off and restarting."

Not sure about what you are worried about here. The D250S is an MPPT solar regulator. They periodically interrupt the charging to check the available output from the panel and adjust their operation to achieve the maximum possible charge rate.

Quote "It also seems that when my fridge compressor kicks in, this also causes the CTEK to restart."

This is a feature of most smart chargers. Their absorption stage maintains a constant voltage charge. With this constant voltage the charge current drops off as the charge level of the battery rises. When the charge current drops to a few percent of the chargers maximum the charger assumes the battery is fully charged and it switches to float charge.

When you draw some current from the battery, if there were no charger attached the terminal voltage will drop a little. With a charger in operation the charger supplies more current to counter the drop in that terminal voltage. If this increase in charge current exceeds the current where the charger switches to float voltage, the charger reverts to its full charge cycle. All the chargers I have had experience with will do this. I am yet to see one that advertises that it does not.