The
solar panel on our roof is producing all the hot water we need at
this time of the year. We have a single collector panel on the
roof consisting of 25 evacuated tubes each 1.5m long. The system
was installed just over a year ago and although we have had some
teething problems, the system is working perfectly. The problems
were with the 12 volt pumping system that circulates the water from the
collector panel to our hot water storage tank. The pump is powered
by a wet cell battery similar to a motor cycle battery and is charged
by a small photovoltaic panel also situated on the roof. In order
to prevent the battery from 'overcharging' - it is necessary to
include in the sytem an electronic 'charge controller'. This will
allow the battery to charge to it's maximum capacity but not overcharge.
It also prevents the battery from discharging via the photovoltaic
panel during the hours of darkness. The 'charge controller' fitted
initially was the cause of the problem. The firm that fitted
the system seemed to have a poor knowledge of the electronics and
just replaced the battery. This cured problem for a short time but
the problem soon re-appeared. After many telephone calls and
and letters and engineers that failed to appear, I decided to try
to cure the system myself. First I obtained a new battery (a
little bigger than the original/s) and I found that in spite of
excellent weather (sunlight) the battery was loosing it's charge. I
checked the voltage from the solar panel and that seemed OK. So
I obtained a more sophisticated Charge Controller and fitted that. The
result is that the system now works perfectly and the outfit that
intalled it is about to get a bill from me.
Photos
are..... 1. The collector
panel on the roof 2. The
control sytem (set to switch on pump when collector temp. is 10degC
above water temp.and switch of when collector temp. is 8deg.C above
water temp. Here the collector temp. on roof is 76 deg.C and
the water temperature is 66.2deg.C. (bloody hot) 3.........The
new Charge Controller
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