On todays market there are only two types of batteries Leisure and Deep Cycle, both can be used as winching battery but MOST common is Deep Cycle (Starting
Battery) with a minimum 650CCA.
Deep Cycle Batteries (Starting battery) are built to directly power electric motors, heating elements, winches, compressors, fridges, information processors
and other electrical devices. they are designed to allow repeated full 'dis-charging' and charging without shortening the lifespan of the battery.
An ordinary lead-acid car battery is kept topped-up all the time by the car alternator and never runs flat. If it does - its life will be foreshortened
significantly as it cannot survive being below 90% charge for very long. This is a trade-off in the form of CCA power instead.
Deep Cycle Batteries by contrast are built with heavier charge and discharge cycles in mind and can be used up fully / remain uncharged for longer periods
of time with less deterioration and fewer adverse affects on the overall performance.
Generally a 3 figure number the 'Cold Cranking Amps' (CCA) are the battery's ability to throw plenty of power into the starter motor and engine first thing
in the morning or otherwise from 'cold'.
The 'cold' refers to when the engine is started from cold - e.g. the engine has cooled to below a few degrees celsius whilst the vehicle has been parked
A cold engine, as opposed to one that has just been running at optimum temperature, will take more energy to start and thus needs plenty of CCA from the
battery. The reason for this is that the moving parts of the engine when cold encounter more resistance as they move against one another. Metal (or
metal alloy blends), similar to most materials contract and become physically smaller / tighter when cold. The amount of contraction may only be a
few thousandths of a millimeter but in a car engine where mechanical tolerances are very fine - it can make, especially in older vehicle designs, a
big difference to the job the starter motor has to do.
Diesel engines typically need more CCA for example than petrol equivalents due to them being a much heavier design in general. Diesel engines require certain
parts of the engine to be heavier / thicker walled than their petrol siblings and need more CCA to crank them over at startup- especially in winter!
An older car that struggles to start because the engine isn't as free turning as a newer version simply needs a battery with 5-10% more CCA than the previous
battery! More regular oil servicing will otherwise no doubt help...
PLEASE NOTE :
Your car can take a new battery with the same or more CCA but NOT less!
The charge that a battery holds can be likened to the usable amount of potential energy it has.
Similarly - to charge a battery is to increase that amount of energy to a certain extent so obviously a battery can be full or empty like a cup.
Ordinary Lead Acid batteries such as car batteries need to be regularly charged and kept topped up by the vehicle alternator to keep them working properly.
If, for any reason the battery's energy levels fall below a certain amount and stay there for prolonged periods of time - it will become unreliable.
By contrast a mismatching alternator fitted by a bad mechanic will slowly ruin the battery by overcharging it.
Most types of battery, whilst charging will feel warm to the touch. This is quite normal. If the battery(ies) start to feel too hot to touch then there
may be a problem. During charging, lead acid car batteries generate a by product called oxyhydrogen gas. Oxyhydrogen gas in great quantity in an enclosed
space can explode when exposed to sparks, lit cigarettes and so on.
When most types of battery have overheated the chemical compounds inside will change due to them having been cooked. Generally the unit will at best be
unusable - at worst will melt, deform or explode, often into flames. Smoke or vapors from overheated batteries can also be very toxic. It is generally
a good idea to keep the area around charging batteries well ventilated especially older technology.
Do not couple up any type of battery charger to a battery unless you are certain the pair are suited. Some combinations e.g. using grandads old charger
on your AGM battery will probably, if not definitely cook it.
The same applies to mobile phones and laptops etc etc etc.