Insufficient Solar Supply; Dc Load Too High; Battery Cable Voltage Drop - Victron energy SmartSolar MPPT 100/30 Manual

• Voltage drop in battery cables. Refer to the
• Incorrect temperature compensation setting. Refer to the
• Temperature difference between the solar charger and battery. Refer to the
battery [50] subchapter.
• Battery charge voltages or current settings are too low. Refer to the

8.6.1. Insufficient solar supply

Check if the solar charger reaches the float charge stage each day.
To investigate, check if the solar charger reaches the float charge stage each day. Utilise the VictronConnect app's history tab,
where a histogram displays the daily charging durations in the Bulk, Absorption, and Float stages for the last 30 days. Clicking on
a histogram column provides a breakdown of the charge stages.
You can use the charge times to assess whether the PV array is appropriately sized for your needs.
Reasons for the solar charger not reaching the float stage include:
• An inadequate number of solar panels.
• Excessive DC load.
• PV array issues causing reduced power output.
• Solar charger is unable to reach full output. Refer to the
Please note that this information does not apply to an ESS system. An ESS system will continuously be in the bulk charge stage
while connected to the grid.
Left: Example of a system that is spending all its time in the bulk stage. Right: Breakdown of the charge stages - The system

8.6.2. DC load too high

The solar charger not only charges the batteries but also supplies power for the system's DC loads, such as lights, refrigerators,
inverters, inverter/chargers and more.
Battery charging occurs only when the power generated by the PV panels exceeds the power consumed by the system's DC
loads.
To check the PV array's power generation and load power usage:
To check the PV array's power generation and load power usage:
• If the system includes a properly installed and configured battery monitor, you can monitor the current flowing in (or out) of the
battery, while the solar charger indicates the current generated by the solar array.
• Use a current clamp and compare the current flowing from the solar charger into the battery and the current flowing from the
battery into the DC system.
• A positive sign alongside the current reading indicates current flowing into the battery, whereas a negative sign suggests
current being drawn from the battery.

8.6.3. Battery cable voltage drop

If the battery cables experience a voltage drop, the solar charger will produce the correct voltage, but the batteries will receive a
lower voltage, potentially leading to undercharged batteries. An excessive voltage drop of more than 2.5% is unacceptable.
The voltage drop can result in the following:
• Longer battery charging times.
• Battery receiving a charge voltage that is too low.
Page 49
MPPT solar charger manual
Battery cable voltage drop [49]
Temperature compensation setting incorrect [50]
Battery settings too low [47]
Solar charger not achieving full output [52]
spends time in bulk and in the absorption stage.
subchapter.
subchapter.
Temperature difference between solar charger and
chapter.
chapter.
Troubleshooting