electric wiring

[Alain Brauckmann]

Why the batteries are divided into two systems?

Service and auxiliary for the bowtruster?

As I noticed, the auxiliary for the bowtruster are only there for absorbing the peaks when you use the bowtruster?

Wouldn't it be better if they where connected to one system ? 

[Vedat Midilli]

Long cabling might be a problem.

[Alain Brauckmann]

But they are anyway connected thru those cables just divided by an diode? 

[Mike Brown]

It depends on what type of battery they used for the bow thruster. Bow thrusters are like engine starters, they use a lot of energy in a short period of time. The best batteries to use for the thruster and engine are "start" or "dual purpose". They are designed to provide a lot of amps for a short period of time.

Deep cycle "house" batteries are designed to provide a small amount of power (amps) over a long period of time. If you use either type of battery for the wrong application they will live a very short life.

Beneteau should have used "start or dual purpose" for the engine and bow thruster and wired them to the same circuit. They should have used "deep cycle or dual purpose" for the house bank which is on the other circuit. Keeping them on separate circuits helps to keep them properly charged.

BTW "dual purpose" are a compromise for either application and do not perform as well or last as long as a battery designed for "start" or "deep cycle/house"

[Mike Brown]

The relay allows all batteries to be charged at the same time by the alternator, but then isolates the start battery from the house so you do not drain the start while on the anchor.