Bureaucrat, staff, administrator
4,335
edits
Changes
m
→Required Charging Capacity
Finally, we need a reality check. How long will it take each day to re-charge the batteries? An hour would be nice. Several hours would be insufferable, and counter-productive. To determine the <i>Daily Charging Period</i>, divide the <i>Battery Drain Between Charges</i> by the <i>Required Charging Capacity</i> (other loads net out). In the example shown, a flooded cell bank will take 55 min to charge, a gel cell 34 min and an AGM cell 28 min. Obviously a gel or AGM is the way to go, provided you can manage the larger alternator and charger system. Remember that these times are for a hypothetical house bank of 1100 AH capacity. A real example is likely to be several times larger.
== Charging Systems ==
There can be multiple charging sources with automatic switching:
* Shore power charger
* Alternators
* Trickle charger
=== Shore Power Charge System ===
TBD
=== Alternator ===
Each engine (if there is more than one) will have a high-capacity dual-output alternator and multistage regulator, with separate charging circuits for the starter and house batteries. A backup manual switch and regulator are provided. The regulator must be suited to the type of battery: Flooded cells require an equalization charge after the main charge; whereas gel and AGM cells usually do not. Typical vendors are: Ample Power [3], Balmar [4], Ferris [5], Hehr [6], JackRabbit Marine [7], and SALT [8].
If the boat will be unattended for periods at least one engine must autostart on a schedule to keep the batteries charged.
=== Trickle Charge System ===
In case the main charging system fails while the boat is unattended, a solar-powered DC trickle-charge system can be provided. Trickle charging is also a good idea because there are usually parasitic loads on a battery system that will slowly discharge it. Deep discharge batteries do not want to be trickle charged at a high rate: 3% is recommended. Thus a boat with a house bank of 1000 AH requires a trickle charge of 30 AH.
[[Category:BatteriesPrimary]]