Electronics Help

[John Wright]

I am wanting to overhaul the electronics on my boat. I have a 70hp Yamaha outboard, Motor Guide trolling motor, Lowrance depth finder, (2) LED light bars, bilge pump, aerator, navigation lights, and instrument cluster. 
 

I’m wanting both batteries to be separate, and have their own battery switch and fuse panel.

 

For Battery 1, I'm thinking of having my trolling motor and lights hooked up to a fuse panel. I rarely use the lights and want to be able to hook up a generator for bowfishing. I’m also thinking of installing two more light bars in the future.

 

For Battery 2, I’m thinking of having my outboard motor, depth finder, bilge, aerator, nav lights, and instrument cluster hooked up to a fuse panel. Also thinking of installing another depth finder on the bow of the boat. 
 

Seems like a relatively simple project, but I’m curious if others have a similar setup and what they’ve done. All advice is greatly appreciated!

[Tennessee Boy]

It sounds like you’re planning on upgrading your batteries not your electronics.  What you’ve suggested is pretty typical for a two battery system.  What is needed to more precisely determine your battery needs is the power requirements of the items you’re connecting to the batteries.  For example,  fish finders range from 1 amp to 5 amps or more in power draw.  You can find this information in the manuals or online.  You can also use an amp meter to measure the power draw.  You can get a decent amp meter for about $30.   You can also post the exact models of everything here so we can make better recommendations.

[John Wright]

Thank you for the input. It was more of a question on setting up the electrical system and making sure I’m on the right track. Right now there are two batteries and all the connectors are fastened to the positive and negative terminals. I’m really wanting to clean it up where it looks good and is easily accessible. 
 

On battery one, I was thinking of hooking up my lights and trolling motor. The setup I’m thinking of would be the battery, battery switch, fuse panel, then lights and trolling motor hooked to the fuse panel. Then if I go bowfishing at night, I’ll hook up a generator to this battery.

 

On the second battery it’s the same setup, but the motor, depth finder, bilge/aerator/nav lights, and instrument cluster are connected to the fuse panel. 

I have a few current readings but can get more later. Right now:

- trolling motor: 3 Amps

- left light: 7 amps

- right light: 7 amps

- bilge/aerator/nav lights: 3 amps

- instrument cluster: 2 amps

- depth finder: 1 amp

 

[Tennessee Boy]

The trolling motor amperage can’t be right.   A 45 pound thrust Minn Kota has a maximum amp draw of 42 amps.  At low speeds it much lower but you want to design your system to handle maximum current.   What you’re planning sounds good to me except I would not run the trolling motor through a fuse panel.  It’s best to wire it directly to the battery with an appropriately sized in line breaker.  
 

Also connect your outboard directly to the cranking battery,  not the panel.
 

Just make sure you know how many amps will be going through each wire and panel and make sure it’s all sized to handle it.  There are online tools that will tell you what gauge wire you need based on the maximum amps and length of wire.  When entering the length of wire make sure you count the length to the item and the length from the item back to the battery.

[WRB]

You need a 50 amp circuit breaker for each 12VDC battery. Consider a Perkco battery switch.

How do you charge the batteries? 

Tom