Instruction manual

Figure 4-2 Tracer-BN series MPPT charging algorithm

·Bulk Charge

In this stage, the battery voltage has not yet reached boost voltage and 100% of available

solar power is used to recharge the battery.

·Boost Charge

When the battery has recharged to the Boost voltage setpoint, constant-voltage

regulation is used to prevent heating and excessive battery gassing. The Boost stage

remains 120 minutes and then goes to Float Charge. Every time when the controller is

powered on, if it detects neither over discharged nor overvoltage, the charging will

enter into boost charging stage.

·Float Charge

After the Boost voltage stage, Tracer-BN series will reduce the battery voltage to Float

voltage setpoint. When the battery is fully recharged, there will be no more chemical

reactions and all the charge current transmits into heat and gas at this time. Then the

Tracer-BN series reduces the voltage to the floating stage, charging with a smaller

voltage and current. It will reduce the temperature of battery and prevent the gassing,

also charging the battery slightly at the same time. The purpose of Float stage is to offset

the power consumption caused by self consumption and small loads in the whole system,

while maintaining full battery storage capacity.

In Float stage, loads can continue to draw power from the battery. In the event that the

system load(s) exceed the solar charge current, the controller will no longer be able to