As you can see on our website we offer several types of Lithium batteries because these are smaller and less heavy in comparison to AGM batteries. In case you prefer to have AGM or other type of batteries we are able to help you with the selection process.
The capacity of the batteries themselves is indicated as Ah, which stand for Amps-hour. Additionally, the voltage is provided. For electric propulsion for boats, batteries with 6V, 12V 24V and 48V per battery are used. By multiplying these two values gives the Watt-hours or Wh of the battery. For example a 12V battery with 100Ah capacity is 12*100=1200Wh=1.2 kWh. With the capacity indicated as kWh, it becomes much easier to calculate for how long you can drive a boat on a certain power level.
However, this capacity comes with a significant caveat. The calculated capacity only indicates the nominal capacity, which does not equal the actual usable capacity. This is certainly the case for lead-acid batteries. From the nominal capacity only around 65% is actually available for AGM or traction batteries if the life cycle of the battery needs to be optimal. When fully draining a battery can/will cause damage to the internals, which reduces the life expectancy. Thus, the actual capacity is 65%*1.2=0.65*1.2=0.78 kWh. This reduction is valid for lithium as well, only in the case of lithium based batteries the actual capacity is around 85%. With the higher discharge capacity of lithium more power per weight is available.
For optimal performance of the system, it is advised to use lithium based batteries since these have a higher power per weight ratio. This results in either a longer operational time for an equal weight to lead-acid or equal performance for a lower weight. When performance is not the main driving factor, but costs are. The AGM lead-acid batteries still offer a highly competitive picture due to lower purchase costs. In case of specific application question please contact your dealer/service point