Is there a recommended storage voltage for 18650 rechargeable batteries?
When it comes to storing 18650 batteries, there are a few things to keep in mind. 18650 batteries drain with time so you'll want to recharge them about once a month to be sure they have a full charge when you need them. When you receive a Fenix battery, they're typically around a 60% charge so we recommend you charge them completely and then continue to charge them every month or so.
As for storage, there is no specifically recommended storage voltage, but it's important to consider the temperature and dampness of the location where you'll be storing the batteries. Ideally, you'd want to store them in a dry location around room temperature. Also, if you own multiple lithium ion batteries, you'll want to make sure they don't make contact with one another as this could be potentially dangerous.