PT-100 Manual

ManualsBrandsMagnum Energy ManualsCharge ControllersPT-100 Charge Controller

Page 63

Operation

4.4 Charger Control Operation

As a charge controller, the PT-100’s primary function is to monitor and charge the batteries

appropriately when PV power is available, and to prevent the batteries from being overcharged.

When PV power is connected to the PV input, the charge controller begins monitoring for acceptable

PV power and begins charging the batteries once it has accepted the PV input. The PT controller

uses up to four different charging stages to help monitor and keep the batteries healthy. The four

stages include an automatic 3-stage charging process: Bulk, Absorb, and Float (see Figure 4-9);

and a manual Equalization (EQ) charge stage. The automatic 3-stage charge process provides

complete recharging and monitoring of the batteries without damage due to overcharging. The

EQ stage (requires a two pushbutton press to enable) is used to stir up stratiﬁ ed electrolyte and

to reverse any battery plate sulfation that may have occurred.

Bulk Charging: This is the initial stage of charging. While bulk charging, the charger supplies the

battery with controlled constant current (up to 100 amps). The charger will remain in bulk charge

until the absorption charge voltage (determined by the Battery Type selection) is achieved. The

BULK (blue) LED comes ON to indicate the PT controller is in the Bulk charge stage. The controller

begins each new day (new day = 2 hours without sun) in the Bulk charge stage.

Absorb Charging: This is the second charging stage and begins after the absorb voltage has

been reached. Absorb charging provides the batteries with a constant voltage (determined by the

Battery Type setting) and reduces the charging current in order to maintain the Absorb Voltage

setting. The controller’s ABSORB (yellow) LED comes on to indicate it is in the Absorb charge

stage for a time period (determined by the Absorb Time setting), then switches to ﬂ oat charging.

Info: While absorb charging, the timer inside the PT controller that is used to determine

how long to stay in the Absorb charge stage, only counts when the battery voltage is

at the Absorb Voltage setting. This means the PT controller will be in the Absorb charge

mode longer than the Absorb Time setting if conditions prevent the PV array from

producing enough power to maintain the batteries at the absorb voltage level.

Float Charging: The third charging stage occurs at the end of the absorb charge time. While

ﬂ oat charging, the charge voltage is reduced to the ﬂ oat charge voltage (determined by the

Battery Type setting). In this stage, the batteries are kept fully charged and ready if needed. The

charge controller’s FLOAT (green) LED comes on to indicate ﬂ oat charging. The Float charge stage

reduces battery gassing, minimizes watering requirements (for ﬂ ooded batteries), and ensures

the batteries are maintained at optimum capacity. Note: If the battery voltage falls ≤12.2 VDC

(12-volt system), ≤24.4 VDC (24-volt system), or ≤48.8 VDC (48-volt system) for more than 1

minute, the controller will re-initiate bulk charging.

Bulk Charging Absorb Charging Float Charging

Voltage

Current

Max Charge

Amps

Absorb Done Time

CURRENT & VOLTAGE

TIME

Absorb

Volts

Float

Volts

First Stage

Second Stage

Third Stage

Figure 4-9, Automatic 3-Stage Charging Graph