Mon 9-12-2021 11:59 p.m.
For some time now, I have been collecting and repairing discarded tools and appliances which are provided with internal batteries. Batteries have a limited life-time. The batteries may fail to charge. The battery casings may also corrode inside the tool or appliance causing further damage.
Many tools and appliances are provided with a power pack which is used to re-charge the batteries. The power packs have a specified voltage and a relatively low amperage. Periodically, the batteries require re-charging so they provide an electric motor with the necessary voltage at a higher amperage. Typically, a higher amperage is necessary to operate a direct current (DC) motor. If a battery charger is connected directly to the DC motor in a tool or appliance, then the tool or appliance would most likely run very slowly.
To operate a tool or appliance at the proper speed when the batteries fail, it is possible to remove the batteries, do some simple re-wiring, and use a replacement power pack with the same voltage as the original power pack. However, the replacement power pack must have a higher amperage rating than the original power pack. For example, an original power pack might provide 5 volts DC at 0.18 amps which is normally used to re-charge the batteries. With the batteries removed from the tool or appliance, it may be necessary to use a 5 volt DC power pack with a 1 amp rating. It will also be necessary to keep the power pack attached to tool or appliance (that is, the tool or appliance is not portable anymore). (Note: Toy train transformers which operate at different voltages are useful for determining the power requirements for a tool or appliance.)
Many tools and appliances which are provided with batteries are portable. However, replacing the batteries is necessary if the tool or appliance is to remain portable. Many times, tools and appliances with dead internal batteries are simply discarded. However, locating an appropriate replacement power pack can give a tool or appliance new life even if the item is not portable (that is, the tool or appliance must have a power pack which can remain plugged in to a 110 VAC electrical receptacle when the tool or appliance is in use).
There are a variety of tools and appliances which can be provided with higher-amperage power packs from discarded computer hardware or other appliances. For example, drills typically require a power pack with 12 volts DC to 24 volts DC. After removing the batteries and doing some re-wiring, a power pack with a 12 to 24 volt DC power pack can be used provided the amperage rating is higher than the original power pack.
Caution: Proceed at your own risk. If you do not have any basic repair skills, you may be better off discarding the tool or appliance. However, some experimentation (that is, battery removal, re-wiring, and use of a different power pack) may provide you with a tool or appliance which is still serviceable. (Note: The proposed modification will most likely void the Underwriters or UL certification on the tool or appliance. Therefore, it is recommended that the power pack for the tool or appliance be unplugged from a 110 VAC receptacle when the item is not in use. To avoid the risk of a short or fire, make sure to properly insulate any wires as needed. )
If the tool or appliance contains Nickel-Cadmium (Ni-Cd) batteries, make sure that you dispose of the batteries properly.
To date, I have repaired an electric wine bottle cork remover, an electric razor, a small vacuum cleaner, a hex-bit driver, an electric drill, and an electric pencil sharpener.
Have fun and be safe.
Regards,
ag01
