Battery Management

Battery management is something everyone has to deal with unless the sensors are wired, in which case, it’s not a problem. However, having just one battery-powered sensor makes this relevant. The more sensors you have, the bigger the challenge becomes in the long run. One day, one of your automations will stop working because a sensor ran out of battery, and that’s annoying. Not every sensor requires the same amount of power; some will last longer than others. To complicate matters further, different sensors may use different batteries, and often these batteries are not the standard sizes you can find everywhere.

To mitigate this, we need a few things:

• An inventory of what sensor uses what battery
• Active monitoring
• Quick response

Inventory

This can take many forms. It can be a Word document, a piece of paper with handwritten notes, or a Lovelace markdown card(s). The important thing is to have this information readily available; it will make the whole process a lot faster. List all the different sensors in the house and what kind of battery each one uses. You can get as fancy as you like by using images and other details, but just having a menu of what battery you need for each sensor beforehand makes a big difference. You can also include details about your battery stock in case you choose to buy a bunch and have them available whenever needed. Highly recommended maneuver.

Active Monitoring

Home Assistant has many cards and ways to visualize battery levels, some even with color. Just having this isn’t enough unless you’re constantly checking, which is not ideal. What’s ideal is to have a notification system in place. This system will allow you to set a threshold to send a notification when the battery level of any sensor drops below it. Between 5% and 10% seems to be the sweet spot; higher allows procrastination, and lower might not give enough time to replace the battery.

https://github.com/cbulock/lovelace-battery-entity

https://github.com/maxwroc/battery-state-card

https://community.home-assistant.io/t/low-battery-notifications-actions/653754

Quick Response Plan

This is about having a stock of batteries and acting fast as soon as the notification pops up. When the notification appears, it’s a matter of time before the sensor stops working. Having to go to the store to get more batteries adds to the delay. It might not be a problem, but it’s worth considering because ’not having batteries available and forgetting to get them when going to the store’ is the leading cause of broken automations.