Dulas Solar VC150, Handbook

Page: 65 / 156

65
C.5 Checking the Performance of the Solar Array
NOTE 1: It is only necessary to check the performance of the solar array if you
believe there may be problem with it. For example if the user reports or the
daily record sheets indicate that the “Do not freeze Ice Packs” or
“Refrigerator Disconnected” indicator lights are often lit.
NOTE 2: You should only check the solar array on a day when the sky is clear (no
clouds) and at about midday.
NOTE 3: Before disconnecting any cables label them so you know where to
reconnect them.
1. Clean the solar array (see page 54)
2. Check that the solar array is not shaded (see page 54)
3. Disconnect from the solar array, the array cable that leads to the charge
regulator.
4. Measure the short circuit current of the solar array (see page 52)
5. Measure the open circuit voltage of the solar array (see page 51). It should be
17-20 volts for a 12-volt system.
6. Disconnect one module from the array and measure the short circuit current
of the module (see page 52)
For 12 volt systems the short circuit current in the solar array should
approximately be equal to the to the current in a module multiplied by the
number of modules (to within 15 %). (For example if the short circuit of one
module is 2.5 Amps and there are four modules in the array then the solar
array short circuit should be approximately 2.5 * 4 =10 Amps.
7. If the array current and voltage do appear correct reconnect the module and
array cable.
8. If the solar array short-circuit current or open current voltage does not appear
correct then there may be a fault with a module or the way the modules are
connected together. Refer to faultfinding task D7 on page 58 to find out what
action is required to repair the fault.