Elecrtronics Power Supply

[Sharpseadog]

All of my Raymarine electronics (Axiom 12 & 9, Quantum 2 Radar, Auto pilot, & AIS) and bow thruster are connected to my engine start battery bank (2 group 31 6V AGM in series). Sometimes my analog backup camera blinks out momentarily when I use thruster. Also concerned about starting my Cummins QSB 5,9 with electronics on. Are my electronics in danger from this and if so what do you recommend?

 

[DavidM]

Low voltage is causing the camera to blink off. It is not a good idea to power electronics from high current demand starting and thruster batteries. The heavy current will drop the battery voltage and cause electronics to temporarily drop out.

Rewire to move the electronics loads to the house batteries.

David

 

[Comodave]

Agree, I wire everything except the engines to the house bank. That way your start batteries will not be discharged accidentally by the electronics and you won’t damage the electronics by the start surge when you crank the engines.

 

[fgarriso]

Remember this if nothing else.
All electronics MUST have clean steady voltage with a high level of regulation!
If you have a large load of electronics you may want to install a helm station battery for electronics only.

 

[C lectric]

I will add this so you have an idea about the why of operating your electronics from the house and not the start batteries.

All coil devices, starter motors, thruster motors, fuel control solenoids can and do produce a reverse voltage when they are de-energized which can be several times the voltage that ran them. One thing that can save devices is the battery will absorb a lot or most of the reverse voltage depending upon how the wiring is done. Length of wireing may also help. But damage can still be done.

 

[O C Diver]

As others have mentioned, electronics like a constant voltage and shouldn't be connected to the thruster battery or engine battery.

To go a step further, your bow thruster will perform significantly better if the battery that is powering it is located next to the bow thruster. Long cable runs from the engine room to the bow thruster induce significant voltage dips. As thrusters are DC motors, lower voltage means lower RPMs, means less thrust and more heat.

The other issue with attaching the bow thruster to the engine battery has to do with the ECM on the engine. The ECM will tolerate some voltage dip. But as the engine battery ages, you may find that a prolonged engagement of the bow thruster, when the engine is near idle and the alternator is putting out precious little, may cause your ECM to drop out.

Ted