To charge a battery a panel must be used with a regulator to ensure that the input does not exceed the charging voltage, the charge rate never exceeds one tenth the capacity of the battery - e.g. 6A (Amps) for 60Ah (Amp hour) battery - and that the battery is not over-charged. These precautions are necessary to maintain the battery’s life.
Type of regulator needed
The capacity of the regulator needs to be matched to equal or exceed the input from the panel and the output required by the load. In most cases the input is the crucial factor and so you need a 5A controller or greater for up to 80W of panels and a 10A controller or greater for up to 160W of panels and a 20A controller or greater for up to 320W of panels.
AKT Solar provides a range of regulators with different capacities to suit different panels and batteries. When purchasing a regulator it is useful to remember that a higher capacity (more powerful) regulator will always work with less panels and can then have more panels added to it if you want more later.
Type of panel needed
The power of the panel (the Wattage) should be chosen to be sufficient to both charge the battery as quickly as required and to provide for any other daytime needs.
For a 50Ah battery the 80W AKT-80-M would typically be easily sufficient to charge the battery from half-charge each day during summer in the UK (when the average irradiance per day is between 4.5 and 5.5 kWh/m2).
For a 100Ah battery (typically used in caravans and boats for providing lighting) two AKT-80-M panels in parralel would be sufficient.
Type of battery needed
It is important to note that if the battery is likely to be significantly discharged during its normal use (which is usual when used in a solar system) a "deep-cycle" battery should be used rather than a typical starting battery. Deep-cycle batteries are designed to be regularly discharged as much as 80% and have thicker, solid, electrode plates whereas typical starting batteries have sponge electrode plates which have a greater surface area and more "instant" power but a lower life-span if regularly significantly discharged. Indeed, even with deep-cycle batteries, although they can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge and to recharge up to 100% as soon as possible (within a few days) after discharge.