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 or absorption 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. There are four press-in standoffs in the bottom of the chassis. These have a minimum of 0.187 inch of available 6-32 threads to be used for mounting. Also, there are two 0.201 mounting holes in the side and the bottom of the chassis suitable for #10 hardware.
The charger dissipates approx. 15 watts under worst-case conditions (high line and low battery voltage). Most of this heat is transferred to the charger's chassis, which acts as a heatsink. Sitting on a bench, the chassis becomes quite warm at full output current. If the enclosure is metal and the charger is bolted to it, the enclosure acts as an extension of the heatsink and transfers some of the heat to the outside. When using a small, non-metallic enclosure, a small fan may be necessary to keep the enclosure temperature within the 60C maximum. This is as important for the battery as for the charger. With a large enclosure and adequate ventilation, a fan should not be needed.
LED Signals The charger has two signals available to power customer-supplied LEDs or interface to TTL/CMOS logic. The " +PWR" (power) signal indicates that the charger is being powered. If the power to the charger is interrupted, the +PWR signal goes off. The "+CHG" (charging) signal indicates that the charger is in bulk or absorption mode. When the charger switches to float mode this signal goes off.
The CHG signal is supplied from a 5V source via a 300 ohm resistor and may be fed directly to non-resistor LEDs or TTL inputs. This 5V source has little pull-down capacity so a pull-down resistor may be needed for TTL interfaces. The PWR signal is supplied from the unit's raw DC power (approximately 12V) via a 1K resistor. This may be fed directly to an indicator LED.
Input Power The charger is designed to be powered from a 115VAC or 230VAC 50/60Hz line. The line input should be externally fused at 1.0A(115VAC) or 0.5A(230VAC). The four power transformer line terminals should be connected as follows. It is important that both primary windings be used. Do not use the charger with just one winding connected.
Charging Cycle When AC power is turned on, the charger will begin a charging cycle (described below).
This will occur even if the battery is fully charged.
A fully charged battery will draw a miniscule charging current and will not be damaged by the charging cycle.
This charging cycle will last for at least 2 hours.
A charging cycle will also be initiated if the charger goes into current limit.
This may be because the load has drawn more than the maximum current capability of the charger.
Enhanced 3-Mode Charging This unit automatically charges the battery in three modes (bulk, absorption, and float charging).
Because the charger is controlled by a microprocessor, it has the "intelligence" to determine whether or not a load is connected across the battery as it is being charged and to compute the ideal charging time for each charging mode. Because of this, the charger can be used to charge stand-alone batteries or as a combination charger/power supply. In either application, the charger properly charges the battery, using each of the three charging modes, with no danger of the charger locking itself into the absorption mode.
Mode 1 - Bulk Mode The charger is in current-limit and delivers its maximum rated current (1.5A) to the battery. The "CHG" signal is on. It is in this mode that the battery receives most of its recharge. When the battery voltage rises to approximately 14.7V, the battery is at a 75% to 90% recharged level and the charger switches to absorption mode.
Mode 2 - Absorption Mode The charger is in a constant-voltage mode delivering approximately 14.7V to the battery. The "CHG" signal remains on. It is in this mode that the battery is brought to a 100% recharged level. The charger's microprocessor calculates how long to keep the charger at the elevated absorption mode voltage. It doesn't matter if a load is across the battery during charging. The charger compensates for any current stolen by the load and completely recharges the battery.
When the battery is at a 100% recharged level, the "CHG" signal goes off. However, the charger may remain at an elevated voltage for several more hours before switching to the float mode voltage.
Mode 3 - Float Mode: The charger is in constant-voltage mode at a lower voltage than in absorption mode (approx. 13.8V). This allows the battery to draw just enough current to make up for its internal leakage current. When the charger is in this mode, the battery may remain connected to the charger for all of the battery's service life with no damage to the battery.
If the battery is removed while being charged (the "CHG" signal on), the charger attempts to continue charging the (now-disconnected) battery. It automatically resets itself to the float voltage after an hour or two. If the battery (or a different battery) is connected to the charger during this time, the charger figures things out and re-calibrates its charging times to properly charge whatever battery is connected to it.
Battery Connection Connect the positive battery terminal to the charger's "+BAT" terminal. Connect the negative battery terminal to the charger's "-BAT" terminal. 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 the load doesn't consume all of the charger current).
Do not over tighten the terminal screws. The proper torque is 50 inch-ounces (0.4Nm).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. Size the battery wires and the fuse according to the current draw of the application.
The charger is designed to be connected to a battery. Without a battery, a 1000uF/35V (or larger) capacitor is needed across the charger's battery terminals to maintain stability.
LED Connections Connect the anodes (+) of the user-supplied indicator LEDs to the "+CHG" and "+PWR" terminals. Connect the LED cathodes to the battery negative terminal. Use LEDs or LED assemblies that do not have series resistors unless it is desired to reduce the LED current further.
Load Connection Connect the optional load directly across the battery.
Recommended Battery Size 4.5Ah or larger
Note that some batteries can not be charged at a C/3 rate (this corresponds to a 4.5Ah battery charged at 1.5A). Check with the battery manufacturer. It may be necessary to use a larger battery.