The HM-5 uses an EVE ER 14250 3.6V battery which is a 1/2 AA lithium battery.
See the attached datasheet for the EVE ER 14250.
You may Google "ER 14250" and find several manufacturers that produce this type of battery. Besides EVE, we believe that the following are compatible (though not tested by Solutionbee):
- SAFT LS 14250
- Ultralife 14250
- Tadiran TLL-5902
The cost of this battery varies between $2.00 and $5.00 USD.
Replacing the Battery
- Peel back the corners of the label on the HM-5's electronic module. This will reveal four screws. The picture below shows one corner peeled back.
- Loosen the four screws with a few turns carefully with a Phillips screwdriver without stripping the screws until the module cover is loose (press down firmly on the screwdriver while turning to avoid screw head stripping). It is not necessary to loosen and remove the screws completely... a few turns alone will do.
- Carefully open the top cover. Wires connect the to halves of the electronic module so do not separate the two halves completely.
- Note the battery holder. Remove the battery and replace it with a new one. Note that the existing battery is held in place with glue from a glue gun in order to keep it in place during transportation.
- Some batteries will be held together with the battery holder with wire ties (more recently). You must cut the wire tie in order to remove the battery. Reattach a wire tie to hold the battery in place after replacement.
- Close the cover and tighten the screws.