4.1.6 Determine wire size required from solar panels to charger and batteries from Table 1 below.
Wire size from solar panels to SC-2030 and from SC-2030 to batteries must be much larger for low voltage systems compared
to 120V house wiring to minimize power loss. The required size depends on (1) total maximum amps to be delivered by the
panels, (2) the system volts (12 or 24), and (3) the wire length. The recommended maximum lengths assume a 3% maximum
power loss using copper wire in a 12V system. Doubling lengths will increase loss to 6%. However for 24V system double all
lengths for 3% loss. All wiring must meet applicable electrical code requirements with respect to maximum current versus
gauge. With less than 3% power loss, this is normally not a problem.
*This wire gauge exceeds the terminal block’s maximum wire size and requires adapting.
** Not recommended
4.1.7 Install TM-2030 monitor if not already installed according to "Installer's instructions for TM-
2030
"
4.2. Verifying that TM-2030 reads volts and amps correctly
Proper charging depends critically on accuracy of TM-2030 voltage and current (amps) readings.
Check volts:
For accurate battery-voltage control, the TriMetric’s voltage-measurement wire (called “B1” in TriMetric
wiring diagram) must be connected directly, or close to the battery’s positive terminal.
Check amps
on the
AMPS
TriMetric display:
●
Under zero-current conditions when all loads and charging sources are off, the TriMetric’s ampere indicator must show 0.0A,
or ±0.1A at most when using the standard 500A/50mV shunt. When using the less common 100A/100mV shunt, the zero-
current value should be between minus 0.02-0.04A —which represents the current drawn by the TriMetric.
●
The discharge current should be measured reasonably. For instance, a 12V, 12W light bulb connected to a 12V battery should
display approximately −1A. This assumes no charging is going on, since the amps display shows charge minus discharge. The
formula for Amps =Watts ÷ System Volts (12V or 24V).
●
Verify that ALL charging sources should be shown as positive amps on the TriMetric TM-2030 when charging. All loads on
the batteries should show as negative values when they are operating. Related to this:
●
The following is worth checking, because this mistake is so common:
Check to make sure that nothing except battery
negative (no loads or charging sources or grounds) is connected to the battery negative side of the shunt—as illustrated in figure