Battery Charger

Danger

THESE INSTRUCTIONS RELATE TO PERSONNEL SAFETY AS WELL AS RELIABLE OPERATION OF HUNTER AND BATTERY CHARGER. IT IS IMPORTANT THAT THEY ARE READ AND UNDERSTOOD.

Description

HUNTER’s rechargeable battery system consists of four rechargeable cells and a HUSKY HUNTER battery charger.

The cells are ‘AA’ size Nickel Cadmium (NiCad) of nominally 1.2 volts, 0.50 Ah and are capable of being charged at 65mA continually.

The special HUSKY HUNTER battery charger is the only unit which may be used to recharge the NiCad batteries when they are installed in HUNTER. The use of an ordinary AC adaptor/battery eliminator may damage HUNTER or the batteries.

Warning

When using the charger be absolutely certain that HUNTER has four NiCad cells correctly aligned and no alternative type is present. Do not even mix NiCads of differing age or state of charge. A risk of chemical leakage, gassing or explosion exists if anything other than a matched set of recommended NiCad cells are charged. Do not attempt charging at temperatures of 5°C or less.

The charger contains lethal voltages, under no circumstances must it be opened, in any way tampered with, or used for any other purpose. It must, of course, be kept dry. There are no user serviceable items inside the case.

If the charger is suspected of being faulty, then the fuse inside the mains plug may be changed for a similar fuse not exceeding 2 amps rating. The charger unit is fully protected against continuous short circuits but if unlikely fault conditions arise which cause overheating to the charger, it will self destruct, quietly and safely. The charger is double insulated, making no earth connection.

Operation

To use the charger unit the following procedure is recommended:

  1. Switch off HUNTER.

  2. Plug the charger into HUNTER’s LEMO connector.

  3. Plug the charger into the mains.

  4. Finally switch mains on.

See LEMO Connector for details of connecting and removing the LEMO plug.

HUNTER operation is possible during use of the charger but the current drain will counteract the charging current and consequently prolong the time to fully charge the batteries. Removal of the cells under this condition is forbidden.

As with all electrical apparatus the charger should be disconnected from the mains when not in use. Only 240 vAC (220 to 250v) mains, 50 or 60 Hz is suitable for standard units. Chargers for alternative mains supplies, e.g. 110v, are available.

Exhausted batteries will typically be fully charged in 12 hours, overnight charging is a popular practice.

NiCad Replacement

It must not be forgotten that rechargeable batteries do not have an unlimited life and will ultimately need replacing as do car batteries. If the batteries become exhausted after little use then the set may need replacing. Their life expectancy can be several years but this is reduced by repeated or prolonged total discharge and by excessively high temperatures.

Note

Several discharge/charge cycles are required before NiCad cells reach their peak capacity. This type of battery will also self discharge, especially at elevated temperatures, which can result in a fully charged set of batteries becoming flat in a few weeks. An occasional charging session, say, every fortnight is recommended if HUNTER is being stored.

Mains Operation

For critical or remote operations, permanent charging may be called for. This is acceptable provided ventilation around the charger and HUNTER is good, but ageing of the cells may be accelerated. Annual replacement would be a prudent action in this instance.