Dual Battery Setup

[TDubya]

I want to install dual batteries in my Bronco. Do any of the vendors offer a dual battery kit? If not, are there any good tech articles to be found? Thanks!

 

[fungus]

http://www.wildhorses4x4.com/product/Painless_Standard_250A_Dual_Battery_Kit/Bronco_Batteries

http://www.wildhorses4x4.com/product/Painless_Water_Resistant_250A_Dual_Battery_Kit/Bronco_Batteries

 

[Steve83]

What performance do you want from these dual batteries that a single battery can't provide? There are several "correct" ways to do it, depending on what you're trying to accomplish. My personal preference is the way Ford set it up for '78-86 F-series & Broncos:

 

[wtkeller1]

I have one of the Painless 250A kits that I has not been used that I would sell. If you are interested email me wtkeller1@yahoo.com.

 

[RRRAAAYYY2]

You can also use an isolator or separator. But I would never use a solenoid like in the painless kit. I have never understood how anyone thought they were a good idea.

 

[lonesouth]

dual batteries are used in boats ALL the time

http://www.amazon.com/BLUE-SEA-SOLENOID-120A-24V/dp/B000OTIPDQ

 

[Bronc-n-Bird]

I have a Cole-Hersee isolator in my boat with 2 batteries. It separates the main battery (used to start the engine) from the secondary (accessories, radio, etc) battery so that you only use the main battery for starting. Whenever the engine is running the isolator ensures that the main battery gets fully charged before charging the secondary battery. You can "jumpstart" the main battery with the secondary battery if it dies.

 

[moe d]

i did that so i could run all my power hogs off a 2nd battery like my winch and lights.. I have a 200 amp alt. going to a 200 amp battery isolator then that splits off to my 2 batteries.. for the 2nd battery i have a 160 amp circuit breaker between the isolator and the 2nd battery. This way if my lights or winch short out, it blows the breaker and i still have my main battery to start my motor.. Great and fail-safe design.

 

[Bronc-n-Bird]

Hmmm. Great idea - going to add a fuse to my setup.

 

[RRRAAAYYY2]

i did that so i could run all my power hogs off a 2nd battery like my winch and lights.. I have a 200 amp alt. going to a 200 amp battery isolator then that splits off to my 2 batteries.. for the 2nd battery i have a 160 amp circuit breaker between the isolator and the 2nd battery. This way if my lights or winch short out, it blows the breaker and i still have my main battery to start my motor.. Great and fail-safe design.

The idea of the isolater is that it isolates one battery from another. So if your winch shorts out, it will keep shorting until the second battery either explodes or is completely empty of power. Other words, you will be having a huge problem. The circuit breaker will protect the alternator from the draw, but not the other problem occuring.

 

[RRRAAAYYY2]

Other option if you want to isolate a battery is to use a battery separator instead of the isolator. You do not lose the 1 volt that you do with the isolator.

The diagrams above will give you the best performance from a dual battery setup. 99% of your applications do not require to have the batteries seperated. Some do, mostly in the RV industry. But if you are winching I would not separate them.

If you wire them like Ford and other manufacturers do you will lose some benefit as ot their internal resistance (more important to stereo guys), and they will not balance as well (which cuts their life span pretty much in half)

 

[RRRAAAYYY2]

 

[RRRAAAYYY2]

As you can see above, the separator is most common in stereo applications. Winches want the batteries connected permanently together.

 

[fungus]

So Ray, if I understand you correctly you're saying the best system most of us could run ie; winching, lights, etc would be one of the above systems without any separator or isolator? Just wire the batteries direct? Would the 2 batts then always work to achieve "balance" between the two thus you'd never run into an "overcharging" problem with one of the batteries? Makes sense if this is what you're saying. I guess just make sure you don't winch BOTH your batts dead!

 

[Bronc-n-Bird]

Major benefit to isolator is you don't draw down the main battery so you know you will be able to start and get out. Some trade offs to consider for sure.

 

[RRRAAAYYY2]

So Ray, if I understand you correctly you're saying the best system most of us could run ie; winching, lights, etc would be one of the above systems without any separator or isolator? Just wire the batteries direct? Would the 2 batts then always work to achieve "balance" between the two thus you'd never run into an "overcharging" problem with one of the batteries? Makes sense if this is what you're saying. I guess just make sure you don't winch BOTH your batts dead!

That is exactly what I am saying.

There is the possiblity that you run both the batteries down to dead when winching. If you do, you will have fried your winch motor and likely your alternator as well. Same as if you did that with only one battery. In other words you should not be doing this to yourself.

If you have a decent alternator, you could winch hard for a minute, then pause just to let everything cool down. The winch will already have surpassed its duty cycle and you could be possibly damaging it. The alternaotr is going to be red hot. Everything will need a chance to breath.

During that time the alternator would also have a chance to catch the batteries back up.

I have been stuck to the point were 10 ton winch blocks broke, 3 trucks were needed to pull me out, etc. None of those times would I have been on a winch for a minute straight.

If you were camping and never checked your batteries you could have an issue without using a separator (or isolator). It is situations like that when you want two separate battery systems. Or if you have a constant large draw like a big car stereo.

But having two batteries wired properly together is better for a winch or plow vehicle.

 

[broncomitch]

my brother has that painless harness. it's one of very few good things that come out of there. it's easy to wire up and it works grate. ill be getting it.

 

[moe d]

The idea of the isolater is that it isolates one battery from another. So if your winch shorts out, it will keep shorting until the second battery either explodes or is completely empty of power. Other words, you will be having a huge problem. The circuit breaker will protect the alternator from the draw, but not the other problem occuring.

alt---- isolator----breaker----battery-----winch..

2nd battery will fry, blow breaker and protect the other battery..

 

[moe d]

The idea of the isolater is that it isolates one battery from another. So if your winch shorts out, it will keep shorting until the second battery either explodes or is completely empty of power. Other words, you will be having a huge problem. The circuit breaker will protect the alternator from the draw, but not the other problem occuring.

A battery isolator is a one-way electrical battery that allows an electrical current to flow in one direction but not the other. A battery isolator typically is used in situations where multiple batteries are required, and its primary purpose is to ensure that the failure of a single battery will not incapacitate an entire electrical system. Battery isolators are used in large trucks, airplanes, boats, utility vehicles and other vehicles that require multiple batteries and backup sources of power.

1.
Mechanics
*

A battery isolator separates multiple batteries from one another to ensure that a vehicle has access to a backup power source. In addition, a battery isolator ensures that a vehicle's electrical system does not pull power from multiple batteries at the same time, which would rapidly drain all the batteries and cause the electrical system to fail. A simple setup is one in which a vehicle contains two batteries, both of which are attached to the isolator. The battery isolator is attached to the vehicle's alternator, which is the device responsible for providing the vehicle with electrical power and for charging the vehicle's battery. The battery isolator uses sensors to determine the number of batteries it is connected to and to draw power from the strongest battery. The idle batteries are charged by the alternator, and the battery isolator can switch power sources if the battery in use suddenly fails.


Read more: How Does a Battery Isolator Work? | eHow.com http://www.ehow.com/how-does_5005295_battery-isolator-work_.html#ixzz1HWd3888f

 

[RRRAAAYYY2]

alt---- isolator----breaker----battery-----winch..

2nd battery will fry, blow breaker and protect the other battery..

Actually the isolator will protect the first battery, that is its whole job.