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Dual Battery setups

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pplblazerdude

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Kingsport, Tennessee
I am looking to install dual batteries and I am stuck. I am trying to decided to either build my own setup or order the 12volt guy kit. I like all the abilities off his kit but I would much rather do it myself. I am good with electrical systems so that is not my issue. I just want to do this right the first time.

So the question is. Share with me what you have and what you would have done different. I want to have the batteries isolated and be able to jump start myself from the aux battery.

Lastley I am planning to run a marine battery as my second battery unless someone can tell me why this would not be a good idea.

Currently I have the stock alternator and then a 1000ca battery.

Thanks

Clint
 
For anything marine, ask Ryoken.

I have the painless wiring kit, whick is not completed yet. You might get a ton of different opinions on this. From not needing duals or just one good battery. If your good with wiring, id just run an isolator. But im no expert at all.



Bump!
 
All you really need besides the second battery,a place to mount it and the wiring,is a continuous duty solenoid ,like a Standard/Blue Streak # SS-584,to isolate one battery,yet allow both to charge while driving...........................................................................................................I saw instructions in the illustrated parts guide Standard had years ago how to hook it up--you just hook the small wire that activates the solenoid to the "ACC" terminal of the ignition switch,and run the positive battery cable to one of the 5/16" studs on the solenoid,and another cable from the stud on the opposite side,to the second battery's positive cable...the solenoid case must be grounded for it to work..................................................................................................I have always read both batteries "should" be identical in a dual battery system for best results...but I've had two "mismatched" ones in my diesel for 9 years with no issues...I guess the theory is,if both dont have an equal number of plates or are different capacity,one battery may backfeed into the other one and discharge it,or one may get more charge than the other....and if one battery is defective,a bad cell,etc,it'll suck the other one down too...
 
you can look in my build for my stuff, it's toward the beginning... there are dozens of ways to do this.. pro's and con's for each usually... diode isolators are a super common method used..

it's a very simple to install system, thus why they're popular... hellroaring, 12vguy, etc all make one.. most guys don't want to actually wrap their head around the why's and what's of a DC system, so it's a good choice for them... i prefer my setup any day, but diode isolators are improving annually..

when referring to marine, I'm assuming you mean deep cycle... nothing wrong with them, bit less cranking amps than a "cranking" bat, but a ton more reserve... I've ranted about batteries in here for yrs, but i wont this time... let's just say, I prefer deep cycle in 95% of the cases...
 
Im running the HELLROARING setup. Its really a neat setup. I have an isolator that connects the batteries and a switch in the glove box. I got the kit that makes the 2nd battery an AUX battery, meaning all my accessories and starting capabilities is based on the main battery, the 2nd battery is strictly backup incase I kill my main battery or to combine the two batts for winching and extra duty.

Its a 3 position switch

Up - Alt charges both batteries & combines both batteries for extra power.

Middle - Alt charges both batteries but all power draw is from main battery

Down - completely takes the Aux battery out of charging circuit, makes truck act as if it only has one battery.

Ive had this kit for a better part of 6-7 years and it has never had any issues at all.
 
These guys probably have better systems.

I split my electrical system on my '79 Ford, and ran an isolator for 10 years with only one failure.
And that was my fault. I jumped someone off with the aux battery and blew a diode.

Since I'm an electronics engineer, I just replaced the diodes with heavier units and never had a problem again.

On my truck, I took the output of the alternator loose and fed it straight into the input of the diode pair.
Took loose everything from the starter battery and ran it to the aux. battery. Left the starter battery hooked to the solenoid.
Took the hookup that used to be hooked to the alternator output and ran it to one output of the diode pair (isolator),
Ran a separate line from the other output to the starter battery.

The alternator output 14.5 volts to both batteries and each took what they needed.
I could leave the headlights, radio, whatever on and it would only drain the aux battery, which was a large deep cycle.
When I turned the key, the other battery would crank the engine since it was still hot.

After a couple of years, I one day left the headlights on all weekend. The aux battery was too dead to fire the solenoid and crank the truck. Plus, it probably would not have fired anyway because there was not enough voltage to run the computer.

Since both batteries had heavy common grounds, I just hooked one jumper cable to each positive post and jumped myself off.

After that, I ran some 2ga wire from each positive post with a Ford starter solenoid in-between.
Fired it with a momentary contact push button from the starter battery.
Thus, I could push a button on the dash, and it would jump its self off.
 
wayne said:
Is there a reason you need a second battery?
Click to expand...

Everyone has their own reasons which Im sure most of us share;

1) Combined power of two batteries for winching or running HD off road lights

2) In my case , its a backup, if my primary batt is dead for some reason, I flip a switch and have an instant fully charged battery to start my truck, this is useful when off roading and your in a tight spot or alone (which you shouldnt go alone). Its safer and easier than a jump box or jumper cables.

3) In the case of someone else having issues, you "could" donate your spare battery to their cause.

etc etc etc.
 
I'm running the 12vGuy set-up and it works great. You could assemble the same thing for a bit less money, but his kit made it easy. I mounted the switch under the hood as I just do not need to access it too often.
 
You stated you had a stock alternator. This is kinda going backwards from what you want. Adding a second battery is an additional load on an already punny alternator. If you want some real power personally I would put the money into upgrading the alternator and wiring FIRST! Then buy a second battery if it's still needed.
 
badmix said:
Im running the HELLROARING setup. Its really a neat setup. I have an isolator that connects the batteries and a switch in the glove box. I got the kit that makes the 2nd battery an AUX battery, meaning all my accessories and starting capabilities is based on the main battery, the 2nd battery is strictly backup incase I kill my main battery or to combine the two batts for winching and extra duty.

Its a 3 position switch

Up - Alt charges both batteries & combines both batteries for extra power.

Middle - Alt charges both batteries but all power draw is from main battery

Down - completely takes the Aux battery out of charging circuit, makes truck act as if it only has one battery.

Ive had this kit for a better part of 6-7 years and it has never had any issues at all.
Click to expand...

When would you ever use the "down" position?

nsxxtreme said:
You stated you had a stock alternator. This is kinda going backwards from what you want. Adding a second battery is an additional load on an already punny alternator. If you want some real power personally I would put the money into upgrading the alternator and wiring FIRST! Then buy a second battery if it's still needed.
Click to expand...

This doesn't account for the idea of having a second battery in the backcountry if you leave an electrical draw on over night and need a way to start your vehicle in the morning.
 
colbystephens said:
When would you ever use the "down" position?
Click to expand...

You could use the "down" position if you want to preserve the Auxilary battery - perhaps listening to the stereo for an extended period of time and you want to keep the aux battery fresh.
 
colbystephens said:
When would you ever use the "down" position?



This doesn't account for the idea of having a second battery in the backcountry if you leave an electrical draw on over night and need a way to start your vehicle in the morning.
Click to expand...

Regardless I would still install a larger alternator FIRST! The batteries job is to start the car. Once the car is started all current should come from the alternator.

If you want a reserve battery I would install a switch with a solenoid so you can add it or remove it when you want.
 
nsxxtreme said:
Regardless I would still install a larger alternator FIRST! The batteries job is to start the car. Once the car is started all current should come from the alternator.

If you want a reserve battery I would install a switch with a solenoid so you can add it or remove it when you want.
Click to expand...

A big alternator does not do any good if you can't start your motor. I run two batteries and they serve me well. When my key is in the off position, the solenoid disconects my aux battery. I have left my headlights on and drained my main battery. I open my hood, switch the solenoid to self-jump, and start my motor. Tell me, how is a bigger alternator going to help me in that situation?:dunno:
My alternator is just fine and charges my system adaquetly. I was just after the extra battery capacity and back-up battery security. That is what I took from the OP question as well.
 
I have the painless kit works great and has saved the day multiple times expecially when my alt. Went out at 2 in the morning 40 miles from home coming back from a wheelin trip I leave mine totally isolated just for that reason just don't forget to turn the switch on to charge aux. Battery occasionally
 
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