will this duel battery setup work? (1 Viewer)

[cruiserdoc]

Pardon my remedial question, I have serious issues with electricity. I want to put in a second battery into my cruiser. My current battery is located in the back of my rig and I would like to put the second battery into the engine compartment area. I understand that to keep this as a 12 volt system I will need to wire them Neg to Neg and Pos to Pos. There is my delemia! Because of some anti theft devices I have installed I have placed a cut off switch and a remote terminal/second cut off switch between my battery and the vehicles positive power output to all the electrical components.
1) Can I put my new battery grounded to the frame and its positive power output to the input side of my relay without any problems?
2) Will both batteries charge with this setup?
3) Do you see anything that I need to do to make this a safe and effective setup?

Here is a schematic of what I am thinking. The area in the green circle is my current set up, the new battery that I want to put in is in the top left of the schematic with the proposed ground and positive leads (dotted red line) marked out

Thanks for any help!

 

[BrianSanDiego]

Hi Doc,
I'll take a stab at it..

Sure, you can run both the battery grounds to separate points. Just make sure they are both going to good solid point like the frame.

Your diagram would work, but it would disable the "sectet kill switch". Thats because power from your new battery would be bypassing that kill switch and would still power the accessories and starter. The second kill switch (labeled terminal) would still work though, be because the power from both batteries comes together before going through the "remote terminal" kill switch.

If you could run power from the new battery to the point that the original battery connects to "kill switch" then all your stuff would work as it does now, but with double the battery capacity and more starting power.

What is your goal in adding another battery? It would be pretty easy to add a solinoid to disconnect a battery when the engine is off, so you'd always have a charged battery to start with.
B.

 

[fieldsken1]

whats wrong with a battery isolator???

 

[psreno]

This would not work very well. The alternator will charge primarily the battery with the lower internal resistance (and additional kill switch resistance and difference in line length etc., etc.)

Also, this config will ensure frequent swaps of kill switches as several hundred starting amps generally does bad things to even the bigger solenoids.

Like Fieldsken says. I just picked up an isolator from the junkyard for $5. JCWhitneys sells the kit for $70.

 

[BrianSanDiego]

whats wrong with a battery isolator???

nuthin', just another way to do it...

 

[fieldsken1]

a battery isolator is so easy i was just wondering why everyone has to find another way to make things harder

 

[BrianSanDiego]

a battery isolator is so easy i was just wondering why everyone has to find another way to make things harder

After a bit of research, it looks like...

The diode isolator is easier to install and more reliable than a solenoid. Drawbacks are the voltage drop across the isolator, and that the starter is only connected to one battery when cranking.

A solenoid has little voltage drop and connects both batteries to the starter when cranking. Drawbacks are that its more complex to wire and less reliable.

After reading up it would be a toss-up for me on which system to go with. For me, having a winch would probably tip-the-scales toward the soleniod, otherwise I'd go with an isolator. Hope this helps
Brian.

 

[mybluetoy]

I just set up a dual battery in my Fj40. Not sure if it will work but I have the one battery I was using and mounted the second battery next to it. I then just ran two short cables, one between the positives and one between the negatives. It seems too simple, but will it work, I'm not sure. Don't mean to hi-jack the thread, just thought that this might be a way.

 

[cruiserdoc]

thanks everyone for the info. I will look into both the solenoid and isolator options. Any and all comments are appreciated!

 

[BrianSanDiego]

You're welcome doc, hopefully it helps a little.

Bluetoy, that will work just fine. Running them in parallel like that just makes the two batteries act as a single big one with twice the capacity you had before.

B.

 

[fieldsken1]

After a bit of research, it looks like...

The diode isolator is easier to install and more reliable than a solenoid. Drawbacks are the voltage drop across the isolator, and that the starter is only connected to one battery when cranking.

A solenoid has little voltage drop and connects both batteries to the starter when cranking. Drawbacks are that its more complex to wire and less reliable.

After reading up it would be a toss-up for me on which system to go with. For me, having a winch would probably tip-the-scales toward the soleniod, otherwise I'd go with an isolator. Hope this helps
Brian.

the voltage drop is only .5 volts no biggie and i dont know why you need 2 batties the start the thing. plus i have all my acc including the winch hooked up the one battery and i still run a kill switch for the battery i use to start the thing with

 

[fieldsken1]

Pardon my remedial question, I have serious issues with electricity. I want to put in a second battery into my cruiser. My current battery is located in the back of my rig and I would like to put the second battery into the engine compartment area. I understand that to keep this as a 12 volt system I will need to wire them Neg to Neg and Pos to Pos. There is my delemia! Because of some anti theft devices I have installed I have placed a cut off switch and a remote terminal/second cut off switch between my battery and the vehicles positive power output to all the electrical components.
1) Can I put my new battery grounded to the frame and its positive power output to the input side of my relay without any problems?
2) Will both batteries charge with this setup?
3) Do you see anything that I need to do to make this a safe and effective setup?

Here is a schematic of what I am thinking. The area in the green circle is my current set up, the new battery that I want to put in is in the top left of the schematic with the proposed ground and positive leads (dotted red line) marked out

Thanks for any help!

by looking at the picture i dont think the kill switch will kill anything like brian said

 

[bj40green]

...................
What is your goal in adding another battery? It would be pretty easy to add a solinoid to disconnect a battery when the engine is off, so you'd always have a charged battery to start with.
B.

As asked before by BrianSanDiego; what is your goal, what is the purpose, what do you gain by this set up?
You have created a "parallel" situation and not an "or" situation so the moment you connect the second battery to the first battery, the full one will equalize with the empty one and you and up with two half full (or half empty) batteries.

Another question is; what is the reason for two switches in series? One is hidden and the other is with a remote control?
My guess is that you want to have permanent power to your anti theft devices in case a smart guy disconnects the main battery. Right?

So the answers to your questions are;
1) Can I put my new battery grounded to the frame and its positive power output to the input side of my relay without any problems? Yes this will work.
2) Will both batteries charge with this setup? Only if you don't forget to connect both.
3) Do you see anything that I need to do to make this a safe and effective setup? This is not a "fool proof" set up. It depends on the user. It's better to wire your anti theft system to the second battery and use a battery switch (activated by your ignition key) wich takes care of connecting the two (for charching) when your engine is running.
Should look something like this. Now you can add your engine kill and remote switch in your Main line.


I hope this will shine a light on your problem.

Good luck,

Rudi

 

[cruiserdoc]

Awesome guys, thnx! As stated above for some reason electricity and me don't mesh! I am going to incorporate a battery switch and devote one battery to vehicle starting and another to electronics/ winches.

My reason for a 2nd battery is 2 winches, an air compressor, and an ARB fridge drawing on my current single battery so I felt a 2nd battery would provide some peace of mind. I'm currently getting my rig set up for Rubithon!

 

[psreno]

I would put the kill switch on the coil (+) or fuel pump. And run a dedicated line to your anti-theft device bypassing the isolator. 4 port isolators can alleviate much of the voltage drop issue across the diode, but that's going to depend on your regulator. W/o isolator you will have problems keeping both batteries charged. It will not enhance your piece of mind in the long run since that is your purpose. JMO.
Battery kill switches are important in case of fire etc., but the same can be accomplished via quick disco connectors and they generally make cleaning soooo much easier they're worth it.

Good Luck any which way you go.