SMPPT Installation & Operation Manual Version 1.0
10
customer to control the maximum battery voltage loss under 1.5%, and control
the maximum voltage loss of solar panels under 2.5%.
The following is the cable length between controller and battery, and the
suggested copper cables:
Cable
Length
Cable Size
in mm
2
Cable Size
in AWG
Voltage Loss
at 10A
(a pair)
Battery Voltage Loss
12V
24V
48V
1m
2.5mm
2
#13 AWG
0.14V
1.2%
0.60%
0.30%
2m
4mm
2
#11 AWG
0.18V
1.5%
0.75%
0.38%
4m
6mm
2
#9 AWG
0.24V
2.0%
1.0%
0.50%
Table 3-4: Cable Length & Cable Voltage Drop
The following is the cable length between solar panels and controller, and
also the suggested copper cables:
Cable
Length
Cable
Size in
mm
2
Cable Size
in AWG
Voltage Loss
at 10A
(a pair)
Solar Panels
Voltage Loss
17V
34V
68V
2m
4mm
2
#11 AWG
0.18V
1.1%
0.53%
0.26%
4m
6mm
2
#9 AWG
0.24V
1.4%
0.71%
0.35%
8m
10mm
2
#7 AWG
0.29V
1.7%
0.86%
0.43%
Table 3-5: Cable Length & Cable Voltage Drop
3.4 Over Current Protection
The electrical equipment used in power circuit must be equipped with over
current and short-circuit protection devices, and there is no exception for
SMPPT Series controller. The controller adopts in the design of common
positive pole inside. We suggest users to install over-current breaker or fuse
on the negative loop of solar panels input, and also the negative loop of battery
output. The capacity of over-current breaker or fuse is 1.25 times of the rated
current.
3.5 Lightning Protection
It is the same as other electrical devices that SMPPT Series controller will
be damaged by lightning. The controller has limited surge absorption capacity.
We strongly suggest users to install lightning surge absorption devices to
increase the reliability of the system.
