Friendly reminder. Winter (@northern hemisphere) is kickin' in.

Do not charge your li-ion cells below 10 degrees Celsius.
Irreversible damage can occur to your expensive batteries.

Meanwhile in the southern hemisphere...

Also, any device with an LCD screen should not be left out where it gets well below freezing. Cell phone, laptop, digital multi meter DMM, some chargers, voltage readout on battery pack, electric bike dashboard, etc...

Is it really that bad?

Thousands of power tools are used and stored in unheated areas all winter.

I have a dmm that lives in my car year round and it's still working.

Where I work, we have to leave our phones in the vehicle so after a 12 hour night shift at -20 my phone isn't too happy but it's still alive.

Obviously not ideal, but we don't get the "critters" from tropical climates either!

PaulM said:

Is it really that bad?

Thousands of power tools are used and stored in unheated areas all winter.

I have a dmm that lives in my car year round and it's still working.

Where I work, we have to leave our phones in the vehicle so after a 12 hour night shift at -20 my phone isn't too happy but it's still alive.

Obviously not ideal, but we don't get the "critters" from tropical climates either!

Click to expand...

Discharging or idle is fine. Charging is not.

PaulM said:

Is it really that bad?

Thousands of power tools are used and stored in unheated areas all winter.

I have a dmm that lives in my car year round and it's still working.

Click to expand...

Many of those things you use are properly sealed against the elements. Unfortunately, you cannot expect this for most of our bike hardware.

Our bike hardware also experiences thermal contraction and expansion, especially controllers and hub motors. When contracting in a humid environment, a motor and controller can suck it moisture, and it will just basically hang out inside all winter..

This happens to your car as well. It's why some exhaust pipes make pinging noises as the hot metal contracts, especially in the winter.

I do not have this problem because i live 4000 feet above sea level, but most people do not.