Actually according to batteryuniversity.com (
https://batteryuniversity.com/learn/article/how_to_store_batteries): “There is virtually no self-discharge below about 4.0V at 20C (68F); storing at 3.7V yields amazing longevity for most Li-ion systems. Finding the exact 40—50 percent SoC level to store Li-ion is not that important. At 40 percent charge, most Li-ion has an OCV of 3.82V/cell at room temperature. ”
What this means is that ideally, for long term storage discharging to 40 - 50% is optimal. But since there is practically no self discharge below about 4.0V which equates to approximately 90% cell capacity, you should be fine. Higher than that can result in self discharge which causes the cell temperature to rise, allowing the battery to discharge to the point that cell voltage discharges to less than 2.0V and storing it that way can result in permanent damage and reduced capacity or failure.
In reality, modern device charge and discharge circuits built into devices like Equinox typically prevent your battery from reaching either of the maximum or minimum cell voltage extremes. This is partially implied by the note on p. 8 of the Equinox user manual:
The detector regulates the battery voltage so that its performance remains constant regardless of the charge remaining in the battery.. Although this is referring primarily to battery operation vs. charge.
Anyway, in regards to the original question, when in doubt simply refer to the detector manufacturer’s recommendations in the user manual which states the following:
Battery Maintenance
Lithium-ion battery performance may degrade if unused for long periods of time. Fully charge the battery at least once every 3—4 months to prevent this from occurring.
Even with correct care and maintenance, Lithium-ion battery performance reduces over time with normal use. Therefore the battery may need to be replaced every few years. Replacement batteries can be supplied and installed by an Authorised Service Centre.
So frankly, for a couple months storage at a time I would not sweat the details of ideal precise discharge level percentages and simply store your Equinox with close to 100% charge and sleep soundly. Just be sure to keep it stored within the storage temp range specified in the Manual and NEVER charge the battery wth ambient temperature less than 32F as that WILL likely cause permanent cell damege. Operation down to about 14F is OK, just don’t charge your battery in extremely cold weather. Familiarize yourself with the three temperature ranges (operating, charge, and storage) listed on page 65 of the user manual.
HTH
