Generally, the best 9v battery for a smoke detector may last anywhere from 6 months to 2 years. Meanwhile, 9V lithium batteries typically have a longer lifespan and may last up to 5 years or more.

Available with five outputs or nine, these pedalboard power supplies can supply current-hungry digital and multi-effects, have a switchable 9V/12V/18V options, and are very budget-friendly ...

9V batteries are often found in devices that aren’t used very often. If you use a NiCd rechargeable battery you may find it completely discharged by the time you need it. Capacitors on the other ...

The exception is the 9v battery which actually has six smaller ... Inside are an octet of Lithium Ion cells. The majority register 0V, but a few have 0.4V left on them. This is not surprising.