- Y. O.
As with the operating temperature range... Manufacturers provide storage temperatures and at certain voltage range recommendations.There is so much noodle-doodle nonsense about the batteries on these bikes. Lands sake they're 18650 Lithium-Ion, same batteries used in laptops. IF you have a problem it's not the batteries, it's the controller.
Even though I'm not even a year into e-biking, I know the 18650 quite well from working with laptops. Hell my 12 cell for my old beach cruiser's headlight was built from cells recycled from laptop batteries.
These things are tough. The 12 cell pack I made from scrap has sat entire winters without being powered on in an unheated garage at temperatures ranging from -11F to 120F+, and still held almost 90% charge from full, without ever losing capacity.
So long as you don't have anything attached to suck on its power and it doesn't run completely flat, you SHOULD be fine. Unless it's the cheapest cells on the planet, there is no reason for it when not connected to lose more than 3-4% a month, without any damage to its max capacity.
Beyond that these crazy claims of battery storage methods are little more than placebo BS. If by specification they have an operating range of -10F to 185F, I really doubt you need to worry about temp when not under load.
The only real issue I would see is if the controller in the battery is too complex for its own good, and you drain it completely flat. Like... flatter than the level at which the controller turns off the flow to protect itself. Beyond that, I call bullcookies on most of these "tricks".
Give it enough charge to keep the built-in controller happy during your downtime, anything else is rubbish.
"Find the enemy and shoot him down, anything else is rubbish" -- Manfred Albrecht Freiherr von Richthofen
You're free to think that you know better.