1.) Conventional Alternator Charging - Basics
Updated Wednesday 12/05/2010 1:13pm
1. By and large, batteries are only 60-70% charged. (see Fig 1)

2. Only 20% (maximum) of total battery capacity is actually available for use with most alternator charged systems.
3. Sulphation of batteries is extremely common in these situations. Even new batteries can be ruined within months.
4. Battery life, and the number of charging cycles, is dramatically influenced by the average state of charge (see fig 2).

5. Mains Chargers, Wind Generators and Solar panels partially alleviate the problem, when available, by making up the shortfall. The engine driven alternator(s) is still the most effective means of battery charging, if properly managed.
6. A common approach to battery problems is to install more batteries and fit a larger or additional alternators. This is not the solution: This approach simply enables 60%-70% of more battery capacity to be charged, faster!
The villain of the peace, the voltage regulator is overlooked.
7. Large batteries are not essential for engine starting. A fully charged smaller battery is preferable to a 60% charged large one, in most cases.
8. A higher charging voltage is necessary at low ambient temperatures, and vice versa. This is one explanation why nearly all vehicle battery problems occur during winter conditions.
9. Most alternators are designed to run hot and at high rotational speeds.