Some interesting notes we have gathered about different battery types (also included in the first) and their impact on devices:
See how the battery stability (voltage) varies by load and temperature, lithium batteries have the best stability:
- Lithium batteries come in voltages from 1.5v to 3.7v, check the correct voltage before using
- Not all devices are tuned to handle the voltage curves of rechargeable (NiMH) and lithium batteries, adjust your thresholds accordingly (e.g. devices with alkaline batteries expect a gradual voltage drop off where as lithium batteries voltage drops very quickly at the end). Conversely NiMH batteries drop off very quickly at the beginning which may cause some devices to shut off or report lower battery levels
The last point is interesting to note, when using this app you should adjust your battery warning thresholds according to the battery used and how the device handles it.
For example, when using a zigbee keypad with this custom DTH which can recognize the difference between the various battery types, it automatically adjust the reported voltage based on the battery chemistry.
Another example, when using a deadbolt lock (like Schlage or Yale) which was tuned for alkaline batteries, if you decide to use Lithium 1.5v batteries, it may last 4-6 times longer and will perform MUCH better with more stability in cold weather and under heavy user because the voltage drop in Lithium batteries is lower than in alkaline batteries.
So here’s a typically example, when an alkaline battery is at 50% capacity and the lock deadbolt motor activates, it creates a big current draw which causes the Alkaline battery voltage to drop significantly. This big drop in voltage can cause the lock to shutdown (even through the battery has life left) and it stop responding completely. On the other hand with the Lithium battery, even at 20% capacity it can handle much large current draws without any significant drop in voltage. This leads to a much longer life (even though it has only 3x the capacity of an alkaline battery).
However on the flip side, since the lock is tuned to report the voltage curve of an alkaline battery (which drops significantly over it’s life), the lithium battery voltage doesn’t drop as much. Consequently while the lithium battery may last up to 6x times longer than the alkaline battery, the lock may report the battery capacity at 95% before the lithium battery dies (since the voltage of a lithium battery is more stable compared to alkaline batteries).
So keep in mind the battery chemistry and the device characteristics before deciding at what battery % you want to replace the batteries. As an example for Schlage deadbolt locks using Alkaline batteries, we recommend 60% is a good time to replace the alkaline battery (for the reasons mentioned above including the fact that these locks tend to have more trouble with the mesh at lower battery voltages). However the same lock using Lithium 1.5v batteries should be replaced at 95% (even though it’ll last 3-6 times longer).
Sometimes when a device uses multiple batteries (e.g. locks or thermostats using 4 batteries), they are often connected in series. If one of the batteries fails, the device will stop working because the failed battery acts like a circuit breaker and prevents the remaining batteries from operating (the resistance of the failed battery increases and this prevents the entire series setup from working). This is particularly common with lithium batteries which develop very high resistance as the battery discharges, so it may help to check the voltage of all the batteries in the device and replace the “dead” battery with a fresh one instead of replacing all the batteries if just one battery has failed.
(originally posted on this topic)