SMP100 Manual
6
Charge Controller
A maximum power point tracker (or MPPT) is a high efciency DC to DC converter which
functions as an optimal electrical load for a solar array, and converts the power to a voltage
and current level which is optimum for charging batteries.
The benets of MPPT regulators are greatest during cold weather, on cloudy or hazy days or
when the battery is deeply discharged. The SolarMax Charge Controller also monitors battery
voltage and temperature to prevent overcharging.
The Charge Controller can accept PV open cell voltages (Voc) up to 230 volts for charging lead
acid batteries. SolarMax produces up to 100 amps of charging current for battery voltages
between 24 and 72 volts.
When charging, the SolarMax regulates the voltage and output current to the battery, based
on the amount of power available from the PV array, the state of charge of the battery and the
temperature of the battery bank.
Charging Lead Acid Batteries
For standard ooded lead acid batteries, vent caps should always be kept in place and tight
during both charging and discharging.
It is very important to monitor the water level in the batteries (if possible). Rell the batteries
as necessary using distilled water. If the batteries need water frequently, recheck the charging
voltage settings of the SolarMax and reduce if necessary.
Three Stage Battery Charging
The three stage charging process results in a more efcient charging of the batteries. The
three stages of charging are the bulk stage, the absorption stage and the oat stage. Your
SolarMax Charge Controller will automatically move from one charging stage to the next as
your batteries require.
Bulk Stage
In this rst stage of the charging, the battery is allowed to have a large constant draw on the
available current. SolarMax uses MPPT technology to provide the maximum available power in
this stage, to shorten the charge time or increase the amount of stored energy.
Absorption Stage
The absorption stage commences when the charging voltage reaches the preset absorption
voltage. SolarMax continues to charge at this constant elevated voltage until the current
reaches the switch to oat preset. Absorption charging applies peak charge until battery is
fully charged. This stage is critical to using the storage capacity of the batteries to their full
potential.