Wiring for adding a second battery
 

So I decided I want to add a second battery and wire it with a Perko switch that will allow to run battery 1 only, battery 2 only, or both batteries together. My boat currently has a Perko battery disconnect switch that is just for one battery. The wiring diagrams for setting up the dual battery switch show that the positive side of the circuit is the switched side. On my boat, the current battery disconnect switch is ground side switched. Im thinking that I can just hard wire the positive terminals of both batteries together and have ground side switching for both batteries.

Is this correct, or will I have to rewire everything for positive side switching?

Re: Wiring for adding a second battery
 

That is not a good way to intercept a DC system. You should always disconnect the positive before the negative even when using jumper cables.

You will want to wire both main positive leads to your new selector switch as well as have an isolator in place so both batteries get charegd as needed when running regardless of the selector switch position.

I still do not know how to link you to another thread, but do a search for that and there are some nice diagrams in some other threads like "help me identify this part".

Hope this helps.

Re: Wiring for adding a second battery
 

I would also recomend reading "Elusive alternator wire" thread.

Re: Wiring for adding a second battery
 

I have the positive leads run through my switch. Like the thought of no power there should somthing ground out. I use battery 1 for general boat and battery 2 for stereo, amp, and air pump outlet. Charge both when moving, but isolate battery 1 when sitting on shore running tunes. That way at the end of the day I know I'm going home.

Re: Wiring for adding a second battery
 

Zackattack,

Not to be quarlsome, but you have it backwards. You should always disconnect the negative cable first to avoid a spark that could blow up your battery or worse.

Shabah 198SE

Re: Wiring for adding a second battery
 

[QUOTE=you have it backwards. You should always disconnect the negative cable first to avoid a spark that could blow up your battery or worse.

Shabah 198SE[/QUOTE]

Yep, I guess you are right:punch_out:

I was taught incorrectly according to Wikipedia and Shabah 198SE.

I stand corrected. Sorry for the wrong info provided.:shakehead:

I am a commercial - Industrial electrician so I feel stupid on this one. Although my knowledge is primarily with AC systems. Grounding and bonding an AC system is critical before the load is connected to a hot source(unless you want to get sparks).

So, I will try and stick to what I know.

I still do not agree with leaving all the positives hooked to battery and disconnecting negative with the switch.

Re: Wiring for adding a second battery
 

Zackattack,

We all suffer from the odd brain fart.

As far as the switch connections, I will steer clear of that one.

Take Care

Shabah 198SE