Capacity (50 percent)
Cold performance (50 percent)
Price is per battery and is from a survey in March 2014.
This test was specifically designed to obtain information about the batteries’ performance when powering a smoke alarm.
The results aren’t an indication of their performance in other devices.
About our test
There were 4 steps in our testing:
- To tailor our battery tests to smoke alarms, we took 3 different alarms and measured their electrical characteristics both on standby and when the alarms were sounding.
- We measured the capacity (stored electrical energy) of each battery by monitoring the time it took when we deliberately discharged each from its initial 9 volts to 5.
- We took another set of our test batteries and half-discharged them using the data from step 2.
- These half-discharged batteries were refrigerated to 6°C and then set up to supply the electric current equivalent to a sounding smoke alarm. We measured how well they performed this task.