Monday, Jun 24, 2013 at 00:26
The above suggested solar panel
test assumes the battery is low on charge, which might not be the case.
A far better way to
test a solar panel's output is firstly to disconnect it from everything, chargers, battery, etc.
Then use a multimeter, set to DC about 30V+ range and directly measure the voltage at the panel terminals when the panel is in full sun.
This should correspond with the open circuit specs labelled on the back of the panel (~21V for a 12V nominal panel).
Next, set the multimeter to DC 10A range (the + probe might have to go into a different socket) and measure the short circuit current of the panel, again, this should correspond to the SC specs on the label.
If you did get a voltage reading above but no current then 2 things might cause it:
the meter's Amp range is blown -
check meter's fuse.
the panel wire/ terminals /
test leads have a bad connection.
BTW, with digital multimeters it does not matter which way its leads are connected to the panel, if they are the wrong way round the display shows a negative reading - that's all.
If both those measurements are OK you have eliminated the panel from your problem.
Using a watt meter is best done after its function is thoroughly understood. For example, one would only get the full panel output wattage reading if, and only if, the battery is very low on charge and *can* accept the full charging current available.
FollowupID:
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