i'm constructing a simple portable speaker/amplifier and want it to contain am integrated rechargeable power source.

What's the best/safest way to integrate a rechargeable battery?

i want it to work much like an electric shaver or mobile phone would, with a transformer integrated into the plug, and with a coaxial power connector used to transfer electricity to the unit.


battery type: probably ni-mh i think? i need something with plenty of ampere-hours, but am concerned about making it safe enough to leave charging overnight. also i need a simple and cheap solution!

  • \$\begingroup\$ Battery Type? As different batteries need different charging methods. Such as Ni-Cad and NiMH can be charged with a constant current source. \$\endgroup\$
    – Dean
    Commented May 22, 2011 at 11:25
  • 1
    \$\begingroup\$ thanks for the response - have amended the question and am now researching constant current source! \$\endgroup\$ Commented May 22, 2011 at 11:44

1 Answer 1


Your best bet is to use a battery management IC. Searching Digikey for "Battery management" and then filtering by battery chemistry and then price, gave me the TSM101/A. For less than a dollar, it seems to be capable of what you want.

Just replace the mains and rectifier portion of the circuit with a wall wart. There are some examples with charge status LEDs.

Here is the data sheet.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.