Deals: Batteries for things (mostly U.S.)

For the more common sizes, AAA up through D, plus 9 volts, I really like the Kirkland batteries sold at Costco. They tend to come in top 5 in battery quality tests by most independent reviewers, including consumer reports, but at really excellent prices. They are much better quality than Amazon basics or most off-brands.

http://www.consumerreports.org/cro/news/2014/10/batteries-that-last-when-you-need-them/index.htm

A note about lithium batteries in home automation devices

Also, it’s helpful to remember that lithium batteries have a different discharge curve than alkaline batteries, and consequently battery reporting can be way off for lithium. They typically stay high for a long time and then drop very quickly.

This “flat curve” is considered a plus by people who favor lithium, as it means you get more power out of them for a longer time. But in battery monitoring situations such as many home automation use cases, it can really throw off your ability to predict when the battery will fail. for this reason you may want to implement a time based replacement strategy for lithium batteries rather than relying on battery reporting.

But since that may mean you are removing the battery while it still has viable life, it can somewhat increase the project cost. At our house we use batteries that were removed on a time schedule from critical functions like home automation and put them in a box we use for non-critical functions like gaming controllers. So we do use the lithium batteries until they are completely depleted, but not in Home Automation devices.

http://batteryuniversity.com/learn/article/choices_of_primary_batteries

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