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Some people have replaced NiCds with standard alkaline batteries.

Be careful not to sand/scrape through the plating! Work very gently. A knife or fine sand paper can sometimes work wonders.

Some apparent battery problems are really caused by surface corrosion on battery or charger contacts.

Even with proper use, NiCds do eventually wear out.

Be quick with the soldering iron and wear eye protection in case of a rupture.

NiCds are easily damaged by heat so if you need to solder leads to them, use batteries manufactured with solder tabs.

Unfortunately, the only way to assure that reverse charging doesn't occur is to discharge each cell separately.

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NiCds that are weak due to overcharging can sometimes be rejuvenated by a full charge/deep discharge cycle.

However, through normal use, it's fine to occasionally run the calculator to the point where it indicates a low battery. This is called reverse charging and will lead to a very early death of the pack. Discharging a pack too far can cause the stronger cell(s) to charge the weakest cell in the opposite direction.

Don't completely discharge packs every time to avoid 'memory effect'.

This overcharging leads to voltage depression which is the most common cause of what is generally called 'memory effect'.Р’В (True 'memory effect' rarely occurs in consumer devices because it requires many cycles to precisely the same states of charge and discharge.)

Don't leave NiCd batteries constantly charging.

Topcat pictures manuals#

Only the manuals for the HP 35 and 45 models say that it's OK to run without batteries, but many collectors feel that even those should have batteries installed for maximum protection and long life. Warning! Most models can be damaged if run from the charger without good batteries installed. Please be careful cutting old packs apart and working with leaking batteries.

The Museum of HP Calculators does not assume any responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this information. This information is supplied without representation or warranty of any kind. Information on 240V only chargers is needed! Chargers are either 120V or 120/240V switchable unless otherwise noted. If you find any errors, please contact Dave Hicks. Incorrect voltage or polarity can damage a calculator. It should be considered preliminary and subject to change. The information contained here was obtained by a combination of measurements and printed data and is subject to error.