Best practice wiring

[bgbird]

Should house current be wired to the "hot" terminal of the battery switch. Currently my boat has the house circut directly connected to Battery 1.
I'm in the process of rewiring the feed to the console and would like to know what is the optimum arrangement

 

[Silvertip]

Re: Best practice wiring

There are three HOT terminals on a battery switch (BAT 1, BAT 2 and COM). Which one are you talking about? What you want the switch to do or not do determines where it goes. If BAT 2 is the house battery, the POS terminal of the battery and the BAT 2 terminal on the switch are one and same. BAT 1 is the start battery so you don't want it there. That leaves COM. House power will be available in BAT 1, BAT 2 or BOTH settings. Under way you would likely use the BOTH setting. At anchor you would switch to BAT 2 to protect the start battery.

 

[bgbird]

Re: Best practice wiring

guess I didn't describe what's going on too well...

The positive from the motor is connected to com. 1 goes to 1 positive, 2 goes to 2 positive. Motor negative is connected to 1 neg, and jumper runs to 2 negative.

Both batteries are identical. I alternate using them by setting the battery switch on either 1 or 2 - never both. It was my understanding that the charging circut will charge if either batter is low - and could potentially overcharge if one doesn't need it.

My house wireiing is directly connected to battery 1. I was thinking of connecting it to the COM. That way, when I leave the boat, and turn off the battery selector (I always do that), I'm sure that all power (except the bilge pump which I'll leave directly connected to 1) will be off.

Is the common practice to connect house to the selector - or directly to a battery?

 

[Chris1956]

Re: Best practice wiring

I think you should upgrade the wiring to install a battery combiner. That way you will dedicate one battery to starting the motor, and the other battery to house usage. Both will be automatically charged, and should the starting battery go bad, you can flip the switch and use the house battery to start the motor. All you need to do is install the combiner across both positive poles, and set the switch to allow the non-house battery to start the motor. This eliminates the need to change the switch settings, and assures a fuly charged starting battery.

 

[Silvertip]

Re: Best practice wiring

If BAT 1 is the start battery and you have the house battery connected to it, what is BAT 2 for? Seems it's just going along for the ride. Never use BOTH? Doesn't it make you wonder why they put a BOTH setting on the switch? It's there, use it. You won't harm anything having paralleled batteries and they will both charge just fine. Some of my diesel cars ran parallel batteries with a heck of a lot bigger alternator than you have with no ill effects.

 

[drewpster]

Re: Best practice wiring

Nothing should be connected to the 1 and 2 posts except the positive battery feeds. All the loads, including the "house" wiring, should be connected to the COM posts.
The battery switch serves as a means of isolating each battery from each other and the loads. This allows you to select an individual battery to use while the engine is off so that the unused battery will not be discharged.
It also provides a way to shut off all power in the event of an electrical fire.
You can provide charging current to the batteries several ways.
You can simply select BOTH on the switch manually, start the engine, and charge both batteries.
You can use a diode isolator connected between your engine's charging circuit and the batteries. (current will only flow one way, isolating the batteries)
You can also use a battery combiner.
Each method of charging has it's own advantages and disadvantages. However no matter which setup you choose the battery switch always connects the same way isolating them from all loads and each other.
The only exception should be your bilge pump circuit.

 

[drewpster]

Re: Best practice wiring

Nothing should be connected to the 1 and 2 posts except the positive battery feeds. All the loads, including the "house" wiring, should be connected to the COM posts.
The battery switch serves as a means of isolating each battery from each other and the loads. This allows you to select an individual battery to use while the engine is off so that the unused battery will not be discharged.
It also provides a way to shut off all power in the event of an electrical fire.
You can provide charging current to the batteries several ways.
You can simply select BOTH on the switch manually, start the engine, and charge both batteries.
You can use a diode isolator connected between your engine's charging circuit and the batteries. (current will only flow one way, isolating the batteries)
You can also you a battery combiner.
Each method of charging has it's own advantages and disadvantages. However no matter which setup you choose the battery switch always connects the same way isolating them from all loads and each other.
The only exception should be your bilge pump circuit.

 

[Dunaruna]

Re: Best practice wiring

Is the common practice to connect house to the selector - or directly to a battery?

The house circuit connects directly to the battery (through appropriate circuit protection). Although there is no set standard, battery #2 is usually used for 'house', battery #1 for starting.