WIRING INFORMATION
8
4. WIRING INFORMATION
4.1
Cable Connections
The PV (Photo Voltaic) panels should always be connected in the highest voltage configuration, yet
do not exceed the voltages as in section 2.9. The advantage of this is that panel current will always
be at its minimum so that thinner connecting wires may be used which reduces voltage drops with
loading and improves cost efficiency.
The cable length from the batteries to the MPPT should not exceed 3m. The cable lengths
connecting the PV panels to the MPPT should not exceed 30m.
As an example, if there are two 40 volt panels rated at 5 amps each and they are connected in
parallel, then the output voltage would be 40 volts at 10 amps. If they were connected in series the
output would be 80 volts at 5 amps. In both cases the power would be the same but in the parallel
configuration a thicker power cable must be used to reduce the volt drop from the array to the MPPT
as well as from the MPPT to the batteries.
Cable thicknesses listed are recommended thicknesses that have voltage drops accounted for up to
a distance of 3m for connecting the MPPT and the batteries together and the bottom table lists
recommender cable thicknesses for cables connecting the MPPT to the panels up to a distance of
30m.
Table 4.1 Recommended cable size connecting Cables up to 30m
between MPPT and PV panels (Single Stranded Copper
Specifications)
MPPT Type
Cable Core Area
Overall Cable
Diameter
10 Amp
6mm²-10mm²
5.4mm-6.3mm
20 Amp
6mm²-10mm²
5.4mm-6.3mm
30 Amp
10mm²-16mm²
6.3mm-7.5mm
Table 4.2: Recommended cable size connecting Cables up to 3m
between MPPT and batteries. (Single Stranded Copper Specifications)
MPPT Type
Cable Core Area
Cable Core
Diameter
10 Amp
3mm²-4mm²
1.8mm-2.2mm
20 Amp
3mm²-4mm²
1.8mm-2.2mm
30 Amp
6.8mm²-9mm²
2.8mm-3.2mm
