Ibex Battery Systems
Mounting The output voltage of the charger is temperature compensated to match the requirements of a sealed lead-acid battery. The charger and battery should be mounted in the same enclosure so they experience the same ambient temperature.
Ambient temperature differences between the charger and battery have little effect during battery charging (bulk mode). If, however, the temperature difference is greater than 10C during float charging, the charger's output voltage may no longer be correct for long-term battery charge maintenance.
The charger is designed to be mounted inside a chassis or equipment rack on four 3/16" (minimum height) standoffs.
Because the charger is small, it dissipates approx 6W under worst-case conditions (high line and low battery voltage). Some ventilation is needed if the enclosure is small.
It is important that the board's heatsink not be allowed to touch a chassis or any other conductor. The charger's current-limited output is connected to the heatsink. Because the voltage is low and the current is limited to 0.5A and is isolated from the charger's +BAT terminal by a blocking diode, there is no hazard involved should the heatsink be grounded to chassis. Neither the charger nor the battery will be damaged. However, the charger will not operate properly until the ground contact is removed.
LED Signals The charger has two signals available to power customer-supplied LEDs or to interface to TTL circuits. The signals are driven from an approximately 12V source in series with 1K ohms. If these signals are interfaced to TTL inputs, they may need to be clamped to a suitable maximum voltage. No LED series resistors are needed.
Output Connector The output connector has four pins with the following connections. Please see the mechanical data sheet for connector specifics.
PWR The signal labeled "PWR" , when high, indicates that the board is receiving line power.
Connect to the + lead of an LED.
The - lead connects to -BAT.
CHG The signal labeled "CHG" , when high, indicates that the charger is in the bulk charging mode (constant current). When the battery terminal voltage reaches approx. 14.7V, the charger switches to float (maintenance) mode (13.8V) and this signal goes low. Connect to the + lead of an LED. The - lead connects to -BAT.
+BAT This is the charger's current output pin and should be connected to the "+" terminal of the battery and, optionally, to a load. When off, the charger draws very little leakage current from the battery (100uA) and so may be permanently connected. The load does not have to be disconnected when charging the battery (provided it doesn't consume all of the current).
The charger is not damaged by a short circuit at the battery terminals. However, in the event of a short circuit, even though the charger is not damaged, the battery may deliver a very large current that may melt wires or cause a fire. The battery should be fused close to one of its terminals. PolyFuses work well and will automatically reset. Size the battery wires and the fuse according to the current draw of the application.
-BAT Connect this pin to the battery's "-" terminal. Also, use this pin as a return for the PWR and CHG signals.
Input Power The six pin input power connector must be jumpered as shown below. It is important that both transformer primary windings be used. Do not use the charger with just one winding connected.
The L12-0.5/115AC charger is designed to be powered from a 115 or 230VAC line at 50 or 60Hz.
The line input should be externally fused at 0.5A (115VAC) or 0.25A (230VAC).
Recommended Battery Size 1.3Ah or larger