Insufficient Solar; Wrong Temperature Compensation Setting; Battery Charge Current Too Low; Batteries Are Overcharged - Victron energy SmartSolar MPPT 75/10 Manual

This chapter does not apply if the solar charger is connected to a VE.Smart Network with a battery
temperature measurement or is equipped with a temperature sensor (MPPT RS).
The solar charger will measure ambient temperature at the beginning of the day, as soon as power is generated by the solar
array.
It will temperature compensate the charge voltage according to this temperature measurement.
Once the solar charger goes into the float stage it will measure the ambient temperature again and will use that measurement to
adjust the voltages again.
If there are large ambient temperature difference between solar charger and battery, the battery will be charged at the wrong
voltages.
An example of this is if the solar charger is located near a window in the sun, and the batteries are located on a cold concrete
floor in the shade.
Always make sure that the ambient conditions are equal for both the solar charger and the battery.

9.3.6. Insufficient solar

Check if the solar charger reaches the float charge stage each day.
To investigate look at the history tab in the VictronConnect App. The histogram displays how long the batteries have been
charged in the Bulk, Absorption and Float stage each day, for the last 30 days. If you click on one of the histogram columns you
will see a breakdown of the charge stages.
You can use the charge times to see if the PV array is properly sized for your requirements. A system which never reaches the
float stage could have the following issues:
• Not enough solar panels
• Too much load
• A problem with the array causing it to have a reduced power output.
• For more potential reasons see paragraph: "PV power or yield less than expected"
Please note that above information does not apply to an ESS system. An ESS system will always be in the bulk charge stage
while grid is connected.
System spending all its time in bulk with breakdown of charge stages - System in bulk and absorption

9.3.7. Wrong temperature compensation setting

If the temperature compensation coefficient is set incorrectly, the batteries can be undercharged or be overcharged. The
temperature compensation can be set via VictronConnect or via a display.
To find out the correct temperature compensation coefficient setting for your battery, refer to the battery documentation. When in
doubt use the default value of -64.80mV/°C for lead acid batteries and disable the temperature compensation setting for lithium
batteries.

9.3.8. Battery charge current too low

Check the "Max charge current" setting in the VictronConnect App or via the display.
If the "Max charge current" has been set too low, it will take longer to charge the batteries and/or the batteries will not be fully
charged at the end of day.

9.4. Batteries are overcharged

Batteries that are being overcharged are very dangerous! There is a risk of battery explosion, fire or acid
leakage. Do not smoke, create sparks or have open flames in the same room as where the batteries are
located.
Page 45
MPPT solar charger manual
Troubleshooting and Support