Isn't it normal for a battery to become less 'efficient' as temperature drops ? Plus the increased demand for in-car heating of course.

The principle of operation of any battery is the conversion of chemical energy to electrical energy and as with any chemical reaction the speed of the reaction depends on the temperature of the components of the reaction.

How much of the range reduction is due to temperature and how much to in car heating. heating is something only Mr Musk can tell you.

An interesting aside to this is the way that lithium motorcycle batteries that can be fitted as replacements for lead acid or AGM batteries have to be "warmed up" to start an engine in cold conditions by loading them first to achieve an engine start.

So why doesn't that work in the case of Tesla? Different type of battery?

Edited by focussed on 08/12/2021 at 23:43

I have always wondered whether the range should recover as the battery warms up in normal use. After all, if it needs cooling it must be generating heat. If you do a long journey in winter, then the percentage of time spent with a cold battery would be lower, thereby having less of an impact on range. What am I missing here?

Here's a demo of warming a cold lithium battery up to achieve a start.

www.youtube.com/watch?v=pD_LloqOau0

Anyone who has worked through a winter in Moscow will remember that it was common practice to remove the car battery in temperatures of minus 20 and take them indoors.

But I remember specifying sump heaters for car destined for Moscow and Ulan Bator where it is common practice to plug them into street supplies on car parks.

I did just this for several Canadian winters 1964-66. My Morris 1100 had a block heater which needed about half an hour pre-warming to start the car at about -20°C. Most car parks had 'plug-ins' and we never moved the battery indoors. Doing that regularly wouldn't have helped the terminals much. I made a double blanket to lay across the engine, which helped to retain some heat when parked outdoors. We had a first-floor flat and our plug-in dangled out of the kitchen window - maybe some owners of an EV will do the same thing.

Although most cars in Alberta were large American models, many of them used 6-volt batteries. I remember someone with a Mini jump-starting one because it had 12 volts ...