The short answer is: buy a new one. The long answer is: the battery can be replaced with a ATC Cordless Phone Battery 3.6V NiMH for Sanik 3SNAAA55HSJ1 3SNAAA60HSJ1 series (amazon, $3.16)(this battery is the correct size and volt, but has a higher milliamp rating) This, actually, is a battery for a cordless phone. The old battery is not meant to be replaced, but this one will work. To do this: 1) remove the base from the unit, 4 screws can be removed with a long narrow Philips head screw driver. you can insinuate the driver into the corkscrew area. 2) pry off the black switch, this can be done with a small flat screwdriver. 3) slide off the silver sleeve from the unit. 4) separate the black plastic clamshell pieces by removing four screws. 5) remove tape form battery and cut wires next to battery. 6) use a dremmel grinder to create more space at inner side of plastic base part(battery will not allow unit to close as it is flat and OEM battery is curved) 7) solder battery leads to unit leads(electrical tape to cover solders). 8) screw unit together. 9) put axle for switch back into place and slide silver sleeve back over unit.(may need some lubricant and coaxing) 10) screw base back to unit(may need to carefully tape screws to driver so you can get them into place 11) recharge(1-2 hours of work).......or BUY A NEW UNIT.
Answers & Comments
The short answer is: buy a new one. The long answer is: the battery can be replaced with a ATC Cordless Phone Battery 3.6V NiMH for Sanik 3SNAAA55HSJ1 3SNAAA60HSJ1 series (amazon, $3.16)(this battery is the correct size and volt, but has a higher milliamp rating) This, actually, is a battery for a cordless phone. The old battery is not meant to be replaced, but this one will work. To do this: 1) remove the base from the unit, 4 screws can be removed with a long narrow Philips head screw driver. you can insinuate the driver into the corkscrew area. 2) pry off the black switch, this can be done with a small flat screwdriver. 3) slide off the silver sleeve from the unit. 4) separate the black plastic clamshell pieces by removing four screws. 5) remove tape form battery and cut wires next to battery. 6) use a dremmel grinder to create more space at inner side of plastic base part(battery will not allow unit to close as it is flat and OEM battery is curved) 7) solder battery leads to unit leads(electrical tape to cover solders). 8) screw unit together. 9) put axle for switch back into place and slide silver sleeve back over unit.(may need some lubricant and coaxing) 10) screw base back to unit(may need to carefully tape screws to driver so you can get them into place 11) recharge(1-2 hours of work).......or BUY A NEW UNIT.