Clear-Com AC850A User Manual

AC850

Battery Charger

OPERATING INSTRUCTIONS

The AC850 Battery Charger is a four-port unit for charging the BAT850 NiMH Rechargeable
Battery Pack, used with the PRO850 Wireless Intercom. AC850 maximum charging time is 3
hours, for a fully discharged battery pack. To operate the AC850, follow the instructions below.

Power

adapter

Figure 1. AC 850 Battery Charger

SETUP

AC cord

Figure 2. Figure 3.

• Plug the connector on the power adapter cable into the receptacle on back of the AC850 as

shown in Figure 2.

• Plug the female connector on the AC cord into the power adapter as shown in Figure 3.

• Plug the other end of the AC cord into an electrical outlet.

A red POWER light adjacent to each of the four charging ports should come on when the power
cord is plugged in. The POWER lights will remain on as long as the unit is plugged in.

HM ELECTRONICS, INC. 14110 Stowe Drive, Poway, CA 92064 USA ● Phone: [phone]

HME# 400G548
Rev B 3/11/10

OPERATION

r

Place a room temperature BAT850 battery pack into a
charging port on the battery charger as shown in Figure 4,
with the + and − signs on the battery adjacent to the + and −
signs on the port.

• A steady amber CHARGE light should come on adjacent to

the charging port, indicating the battery pack is receiving
a fast charge.

• A blinking amber CHARGE light would indicate the battery

pack is receiving only a trickle charge. There are several
conditions that would limit the pack to this type of charge.
The first condition would be when the battery or charger
port is too warm, or if the battery or charger port is too
cold. The second condition is when the battery is below a
specified voltage, which can occur when a battery has been overly discharged. If this happens,
leave the battery pack in the charging port. When the correct temperature range is reached,
and/or the required voltage is reached, fast charging will begin and the amber CHARGE light
will remain steady.

• A steady green READY light will come on adjacent to the charging port when the battery pack is

fully charged.

In general, the capacity of an NiMH battery is dramatically affected by the battery temperature
during the charge and discharge cycles, and by the rate of discharge. The capacity is further
influenced by the age of the battery and overall usage and storage history.

POWER

Red

Figure 4.

READY

Green

CHARGE

Ambe

The AC850 battery charger monitors and controls the charge of each battery in three different ways:

1) voltage sensing circuitry, 2) thermal cutout sensors and 3) maximum charge time of three hours.
Under varying conditions, any one of these control circuits could cause the battery charger to stop
charging prior to a full charge.

Depending on a battery’s state of health, it may require multiple charge cycles to reach a fully­charged state. This is especially true with new batteries, or batteries under heavy usage. A new
battery could take as many as three separate charge cycles to reach full charge.

Under heavy-use conditions, it is strongly recommended that each battery be subjected to an
additional charge cycle at least once a week (twice a week if possible). After the charge cycle
terminates, the battery should be allowed to cool down for an hour and then put back into the
charger for another charge cycle. This will ensure that each battery is reaching full capacity and
the cells are balanced.

It is normal for Nickel Metal Hydride (NiMH) batteries to become very hot toward the end of the
charging cycle. This is an integral requirement of the charging process.

Fully charged battery packs can be left in the charging port indefinitely without harm.
The green READY light will remain on until the battery pack is removed from the port.