Charge Controller for Solar, Wind, & Battery Chargers
Installation and Operating Instructions

Ample Power Models CNTLR-12 and CNTLR-24 October 20, 1999

Figure 1. Photo of Charge Controller

The Charge Controller is a simple, efficient and precise controller designed to operate with charge sources such as solar panels and wind generators to prevent overcharge. It can also be used to disconnect runaway battery chargers, provided that the charger can be operated with the battery disconnected.. Independent open and close set-point adjustments are provided.

The Charge Controller includes a 30/40 Amp relay, but can drive a wide range of relays or solenoids. The relay or solenoid must have a normally closed set of contacts. A solenoid rated for 100 Amps continuous is available. This permits the controller to be used with solar panels of a few Amps to hundreds of Amps, just by selecting the appropriate relay or solenoid. The controller logic is designed to be active when the high voltage limit has been reached. This means that no energy is expended while the charge source is still charging the battery. The drive circuit becomes active when the batteries are fully charged, opening the normally closed contacts.

Mounting the Regulator
Find a dry and relatively dust free spot to mount the Charge Controller. Choose a location that will not be subject to mechanical abuse from falling objects or inadvertent bumps.

Secure the controller to the mounting surface. Be sure that wires are secured so that the controller is not stressed by moving wires.

Wiring the Charge Controller
Wiring diagrams are provided for the controller at the end of these instructions. Be sure to wire exactly as shown, with appropriate wire sizes. All controller wires can be #16 AWG or larger. Wires to the charge sources must be sized according to the maximum current they will be conducting.

After wiring the unit and testing it, be sure to secure all wires so that they will not be subject to motion or other events which might detach them from the controller.

NOTE: For maximum sensitivity and repeatability, the controller is provided with separate sense and power terminals. Although these terminals are wired to the same point in the electrical system, the sense lines have very little current in them, and therefore represent a true measurement of battery voltage.

Charge Controller Operation
The Charge Controller has two set-point adjustments that control it's operation. The output drive signal is active at ground level. That is, the signal drives one side of a relay coil to ground whenever the input voltage is greater than the open set-point. This signal will thus open a normally closed relay or solenoid.

Once the controller reaches the open or high voltage set-point, it latches in the active state and will continue to drive the relay coil until the voltage falls below the close or low voltage set-point.

Factory settings for the controller are 14.4, (28.8) Volts open, and 12.5, (25.0), Volts close. If it is first connected to a battery which is 12.6 Volts, the output may be active even though the output is not greater than the high voltage set-point. It may stay active until the battery voltage falls to 12.5 Volts. In other words, the output state may be indeterminate if the device is powered up when the battery voltage falls between the set-points.

Adjusting the Charge Controller
You csn operate the Charge Controller with factory set-points, or you can calibrate it to your particular application.

The controller can be adjusted after wiring the unit into the electrical system; however, it may be easier to adjust it ahead of time using a variable power supply. The controller will react the same way once installed, if installed properly.

There are two potentiometers on the controller, labeled R8 and R14. R8 is the low voltage, (close) set-point, while R14 is the high voltage, (open) set-point.

Start by rotating R8 all the way counter clockwise, CC, about 20 turns. Next, rotate R14 all the way clockwise, CW, to it's maximum voltage, about 20 full turns CW.

Apply a voltage to the positive sense terminal which is equal to the desired final voltage. That is, if you want the relay to open at 15 Volts, apply exactly 15 Volts to the controller sense terminal, TB1-1.

With the desired voltage applied, very slowly turn R14 set-point adjustment CC until the output drives the relay open. You can listen for the relay, or use a voltmeter attached to the relay coil to determine when it switches to ground.

Now reduce the voltage applied to the controller to the desired point for reconnection to the solar panel. That is, if you want the relay to close at 13 Volts, then apply 13 Volts to the sense input, TB1-1. Now slowly turn R8 adjustment CW until the relay returns to it deactivated condition ...the normally closed contacts will be connecting the solar panel to the battery.

Charge Controller Data

Warranty and Repair Service

Figure 2. Wiring for Solar/Wind control.

Supplement: Battery Charger Controller

Figure 3. Wiring for Battery Charger Control.

Settings for Battery Charger Control
To control a battery charger set the high voltage (open) set-point to the battery manufacturer's recommendations. Set the low voltage set-point to something less than the resting voltage of the battery, such as 12.5 (25.0) volts. The point is to allow the battery to discharge a little, but not completely. Setting the low voltage (close) set-point too high may overcharge the battery if the high voltage (open) set-point is also set on the high side.

To use the Charge Controller as a voltage runaway safety device to protect gel or AGM batteries from a runaway battery charger, set the high voltage (open) set-point to some high value such as 15.5 volts. Then set the low voltage (close) to some low voltage such as 11.5 volts. An alarm such as Ample #2003 can be connected from the Charge Controller's TB2 (PWR) to TB3 (DRV) to provide an audible signal when the runaway is detected.

Ample Power products are manufactured by Ample Technology, 2442 NW Market St., #43, Seattle, WA 98107 - USA

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