You can sometimes unwittingly force the alternator
used in your boats to operate above their capacity. For example, it is very common to increase the available battery
capacity. As the battery
capacity increases, the operating time required to fill them with the same alternator
will increase and you will need to operate your alternator for a longer period of time at a capacity that converges to the power limits.
If the ambient air temperature is above 25C° and the engine
compartment is not well ventilated, the alternator will overheat at full load. The insulation
of the copper windings inside can burn at 100°C and above. Under these conditions, you must protect the alternator from burning.
Some examples of alternator overheat protection measures:
1-Addition of thermostat controlled fan. It works when the alternator overheats. It turns off when the alternator temperature drops to normal.
2-To keep the engine
speed as high as possible in order to increase the cooling
capacity of the alternator fan during charging
3-To cut off the alternator charge in a safe way when the above measures are not sufficient. It allows the alternator to cool down itself quickly.
Another event that threatens alternator is the sudden disconnection from the battery while operating under high charging
load. In the meantime, since the strong magnetic field formed in the stator windings of the alternator cannot find a place to discharge, it creates a very high voltage current
in the alternator. High voltage permanently damages the alternator and/or sensitive electronic devices that are open at that time. This event may occur as a result of the user accidentally closing the battery switch while the alternator is running.
Another scenario is that the Lithium
battery, which is trying to protect itself against high voltage charging, shuts down uncontrollably to protect itself during alternator charging.
Under this topic, it is aimed to exchange information about alternator operation, load-temperature measurements, thermal control circuits against overheating
, external regulators, alternator operations, alternator controls required for Safe Lithium
Please share your past alternator failures on board and tell others why they happened.