In the case of a combustion vehicle's aging battery, this could mean the difference between the vehicle starting or not.

In the case of a camper, whatever type of battery you're using you'll find that your battery bank doesn't last as long in winter.

In the case of a battery electric vehicle (BEV) - which still almost definitely uses a type of lithium battery - if you've tried to use it in extreme cold (or extreme heat) you will have noticed the range is reduced.

While sodium ion battery development promises some advantages for BEVs when conditions get extreme (cold or hot), they're not on the market just yet.

A flooded (electrolyte mixed in water) lead acid battery will either be maintainable (because it will have removable caps allowing you to top up the electrolyte reservoirs with demineralised water or a special conditioning solution) or be maintenance-free (sometimes mislabelled as sealed, because they're only sealed in the sense that the casing is moulded shut to prevent you topping them up; they can still leak when tipped far enough and they still expel toxic gas when charging which is also the cause of the corrosion you find on battery terminals).

Flooded lead acid is still used to start the vast majority of internal combustion vehicles, and you're most likely to find it located in a corner of the engine compartment.

This has a disadvantage in summer because heat does age them a bit earlier.

It has advantages though. Being outside the cabin means the expelled toxic gas isn't building up in the space you need to breathe, and being close to the starter motor means less resistance through a short cable to power it (by far the highest current draw it will experience in normal use).

Another advantage we don't normally think about is how some residual engine warmth can, for a while, keep this battery from getting quite so cold after you park the vehicle in winter.

One more reason using the vehicle regularly won't reveal a weak battery straight away is it will be fully charged when you turn the engine off (assuming the alternator is functioning properly).

Lead acid batteries can freeze too, but the closer to fully charged they are the less water will be separated from the actual electrolyte in the solution and therefore the lower that freezing temperature will be.

All batteries slowly lose charge over time too, but older batteries lose it at a greater rate.

It is these factors in a vehicle left for a couple of days that can mean it really struggles (or fails) to start the engine on a very cold morning (the fuel not turning to vapour nearly as easily in the cold is another factor).

For campers, who are more interested in deep-cycle batteries for their gadgets and lights, if they're still using lead acid it's probably one of the more convincingly-sealed types, either an absorbed glass mat (AGM) or a gelled electrolyte lead acid (GEL). These too can (and do) expel toxic gas, but only as a safety mechanism when overpressure occurs (the gas produced from charging is usually recombined inside the battery).

AGM and GEL are both better in the cold than flooded, but are still adversely affected by it with a temporarily reduced capacity.

Lithiums aren't as affected by the cold as any lead acid, but they are still affected. They currently remain the best choice though, but make sure you use an appropriate means of charging them (eg. solar controllers for lead acid are usually unsuitable for lithium, so you'll need one that's meant for lithium).

Lithium is also good for a portable emergency jump starter because it will be much smaller and lighter than a lead acid equivalent. But, be mindful of the many non-reputable sellers who make impossible overclaims of their capacity and capability (sometimes putting multiple unjustified zeros at the end of the number on the specs).

In the same way that a lead acid battery of a given type and capacity must weight a certain minimum for that capacity to actually be possible, so too is there a minimum weight a lithium battery must be in order to truly hold a given number of amp hours.