Mains power V Battery power
- River City Smoke Alarms
- Jan 12
- 2 min read
Updated: Jan 24
Which one is superior? The age old debate.
Mains powered smoke alarms are better than battery powered smoke alarms.
But are they really?
In our experience, not necessarily. Here's why.
Mains powered or hardwired smoke alarms are directly connected to your homes' 240 volt power supply. This means that they are directly susceptible to any sort of power disturbance or fluctuation from the power grid. Generally, mains powered smoke alarms are rated for nominal voltages between 220 - 240 volts however, grid supply voltages are allowed to fluctuate from between 216 - 258 volts. This can potentially damage the smoke alarm, requiring an electrician to replace it and costing you dollars. Additionally, off-peak ripple injections (a big problem in Brisbane), ceiling fans, fluorescent lighting and even bathroom heat lamps have all been known to trigger mains powered smoke alarms.
So what's the solution, battery power?
Well maybe not.
Battery powered smoke alarms are completely isolated from 240 volt mains power so they are not susceptible to power disturbances from the grid. In QLD, battery smoke alarms can no longer be powered by a 9 volt alkaline battery and instead must be powered by a sealed long life lithium battery which should last the life of the smoke alarm (10 years). However we have seen many of the cheaper smoke alarms start failing outside of their warranty due to inferior batteries. Of course this then requires the consumer to go and purchase another smoke alarm of the same brand to connect to the others in their property. Good marketing? Maybe. But really frustrating. Additionally, battery smoke alarms will have a wireless interconnection between them; when one alarm triggers, all alarms will sound. For many of the smoke alarm brands out there, this wireless connection uses a 433MHz frequency. This is a very congested frequency as many other wireless devices utilise it as well, creating problems with smoke alarms randomly sounding or even not sounding at all.
So maybe we should be focusing on the design of the smoke alarms themselves rather than how they are powered. A well designed smoke alarm should be able to withstand power grid disturbances and contain a high quality lithium battery which will last the life of the alarm.
