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Duel Batteries - Maybe?

ZakRhyno

Full Member
Joined
Apr 5, 2013
Messages
67
I was trying to figure out what do I need to have a duel battery set up. I attack an picture of where I think one should go in to. What do I need to add it and how go will this setup if I want to use a 12V plug for say something like charging my iPhone are run 12V LED lights in my camper shell? Thanks for the help ahead of time.
 

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Yes that is the second battery tray in the 07 up models came standard like that.

You could use one of the painless second battery kits to add one.
 
Painless makes the installation "painless" but there are other options too.. Just depends on what you want to use it for.

The basics are that you want to install a new ground wire and a new positive wire to charge the battery.
If you are not installing anything you will be grounding to the body or frame of your truck then you can just ground the second battery to the block and be OK otherwise you will want to ground to the frame and to the block. The Positive wire I would suggest connecting to any place you can find that is carrying the bigger gauge from the battery.

If you are using the second battery for key off power then you will want to use a separation device such as a battery separation solenoid. This will allow the battery to only be connected when your truck is running to prevent the main battery from being discharged while using power from the second battery.

The Painless battery setup as mentioned is a good kit to use.

Also when choosing a battery you will want to find one close to your main battery for longer life of the batteries and to insure full charge on both batteries. I will always try to steer people away from the optima batteries because they were never designed for use in a daily driver and can damage your alternator if they get discharged too fully.

Rodney
 
While he sold it just today, my brother has a Yukon with a dual battery setup (both Optima yellow tops).  Basically two separate batteries with an isolation solenoid that activates with an ignition ON signal.  He used the aux battery to power his huge amp and subwoofer.  The idea is that he can leave the vehicle in accessory with the main battery powering the stereo head unit and the aux battery running the sub and main 4-ch amp.  If the battery starts going dead, you know it because the stereo starts sounding like crap and the amps drop out.  The main battery is GTG.  Just start the truck to get everything rolling again, let it run for a while to charge up the aux battery, then shut it off and keep rockin'.

The only real concern I have is that starting the truck parallels the batteries during starting which probably causes a pretty big surge on the main battery as the aux battery drags it down while the truck needs CCA to start.  It would be nice to have another signal that only parallels them with the solenoid AFTER the truck is running.  Is there such a signal?

I ask because I just bought a 2011 Z71 and I'd like to install a similar system. 

Don't have to dumb down the answer.  I have an EE degree.  I just don't know all the details of how the truck works yet.
 
You have a valid concern if you do not update from the stock battery to a AGM battery.

The older Isolator kits you have a switch to put in manual isolation, the newer ones will do it automatic. The AGM battery have a low recharge rate so they do not drag the system down, Now if you have big amps you need to upgrade the alternator anyway along with the big 3.
 
MS03 2500 said:
You have a valid concern if you do not update from the stock battery to a AGM battery.

The older Isolator kits you have a switch to put in manual isolation, the newer ones will do it automatic. The AGM battery have a low recharge rate so they do not drag the system down, Now if you have big amps you need to upgrade the alternator anyway along with the big 3.

Oh yeah.  I would be installing two new AGM batteries of the same type.  Might even try to find similar manufacture dates. 

Not planning on running big amps at all.  perhaps a decent size inverter, like 1800W, some auxiliary lights, and maybe like a 300W amp if I'm feeling froggy.  That's about it.  Not a big stereo guy.

I just realized that I could slave a NC relay to the starter solenoid circuit with the contacts in series with the isolator coil that would keep the batteries isolated during the starting cycle.  Or I could still find a source that's only hot when the engine is already running...
 
PromptCritical said:
While he sold it just today, my brother has a Yukon with a dual battery setup (both Optima yellow tops).  Basically two separate batteries with an isolation solenoid that activates with an ignition ON signal.  He used the aux battery to power his huge amp and subwoofer.  The idea is that he can leave the vehicle in accessory with the main battery powering the stereo head unit and the aux battery running the sub and main 4-ch amp.  If the battery starts going dead, you know it because the stereo starts sounding like crap and the amps drop out.  The main battery is GTG.  Just start the truck to get everything rolling again, let it run for a while to charge up the aux battery, then shut it off and keep rockin'.

The only real concern I have is that starting the truck parallels the batteries during starting which probably causes a pretty big surge on the main battery as the aux battery drags it down while the truck needs CCA to start.  It would be nice to have another signal that only parallels them with the solenoid AFTER the truck is running.  Is there such a signal?

I ask because I just bought a 2011 Z71 and I'd like to install a similar system. 

Don't have to dumb down the answer.  I have an EE degree.  I just don't know all the details of how the truck works yet.

I don't think you need to be too concerned - it's the same as if you were getting a jumpstart from another battery.  Also having an EE degree myself I understand where you are coming from but in practice over the course of history of having battery-powered starters in cars it hasn't seemed to be a problem.
 
Dual batteries only help if you run accessories while the engine is not running.

If you DO run optima's you want to run Red tops for a daily driver. The Yellow tops are deep cycle batteries and are more for if you continually run equipment until your battery is dead. Under normal circumstances you would just run a Yellow top as your secondary battery.

You do want to match your batteries however when connecting them with a solenoid so they both charge and you don't reduce the life of one of the batteries due to one consistently getting either under charged or over charged. It is my understanding if you run with a red top as your main battery and a yellow as your secondary battery then you are fine as far as matching them goes.

In your case however dual batteries are a waste of money. You need to consider a bigger alternator for your power draw but a standard good quality battery should be all you need for you system. Dual batteries are only useful if you do a lot of stuff with the engine off. And since you are not running a winch or a high power audio system an optima is a waste of money over just a standard battery.

I had very bad experiences with Optima's in the past and there for I try to steer people away from using them. They were never engineered for daily driver use although they are marketed now differently. I toasted 2 alternators when I was using Optimas. They were originally designed for off roading to help with Winching and such. The lower resistance they have can help pull someone out better. But the whole charging issue is what makes them bad for every day usage. Basically if the voltage drops enough they won't start your vehicle they will act like a short on your alternator and have been known to blow diodes. In my vehicle I had multiple issues with them that went away when I went to a different style battery. Plus as I said, they are a waste of money in your application. However a larger alternator and doing the "big three" upgrade will drastically improve your experience regardless of what you do with your batteries.
 
If I want to run either double or triple batteries all in series and all with key on power and dual 250 amp alternators, do I need an isolater kit? Or would I just be able to run them all in series. Because everything I have read or seen or heard is using the extra battery or two to run things with the key off. So do I need an isolator kit?
 
You want to run them in parallel (+ terminals tied together; - negative terminals tied together) not series with the positive of one battery tied to the negative of another.
 
Okay sweet. And would I just use something like a 4 gauge cable? I am going to go with a national starter dual 270 xp alternator kit. And I will also be doing a big 3 upgrade on both alternators. Should I run a maybe 8 gauge cable to my switch panel and then do a power distribution block to add on all my stuff for my switch panel?
 
I'd still suggest an isolator kit for the batteries.

The size of the cable depends primarily on how much current you plan to be pulling through it and secondarily on how long it is - the longer it is the bigger you want it to be so that you don't loose too much voltage across the length of it which directly correlates with the cable length.  Not knowing either of those makes it hard for anyone to guide you on what cable size you need.
 
True, didnt think about that. Thanks man. Sure helps a lot being on here. Been on here for about 2 years now and it hasnt ceased to amaze me how great this site is
 
ISSCA has a wiring chart for suggested size of wiring compared against length of wiring and power it is intended to carry...

If you are running 2 batteries and two alternators you run a battery to each alternator and no need for isolators.

Otherwise isolators allow you to connect the batteries to the charging system when the truck is running and disconnect the batteries from each other when off so you don't discharge all of them... And yes you hook them in parallel. Series you add the voltages together so 3 batteries would be 36 volts. Semis run 24 volt systems and they will run 12 volt batteries in series...

If you notice from stock the alternator only carries about a 12 or 14 gauge wire... It doesn't pull much power consistently so doesn't need a large wire. If you are running a larger alternator you will have to upsize the wire.

If you are running a large system you could need 1/0 or 2/0 wire... And remember, just as with piping, doubling the size of your wire should quadruple your capacity. (Or if you use 4 4gauge wire in parallel in theory it is the same as a 2 gauge wire.)

The ISSCA table is available on their site and should be used to estimate wire size. ISSCA is a car audio competition association and they have LOTS of good information in their competitor manuals. I believe they are downloadable PDF's last time I looked.
 
So what about if I do this.

Alt 1 to stock battery one to run all stock

Alt 2 to batteries 2 and 3

I will run the batteries 2 and 3 parallel so that way I can have them both charged at the same time

I will run the big 3 upgrades on both alts and use all 2/0 gauge wire to connect the two batteries in parallel to each other

I will run power and ground wires from the second and third batteries to two separate terminal blocks that I will wire all my switches to. Most of the lights will go to one battery and the other components like train horn, on board air, and audio will go to the third battery
 
prompt, thats just dumb. you dont ever let an amp shut off due to low voltage that will kill an amp. not sure what kind of power hes running that he can even let it not run anyways cant be that much.

09chevy how much power you plan on running? that all sounds fine to set up. im not really sure what the switches are for? the grounds are fine to run to the same place. depending on how much power your amps are going to be you may just want to even the load to both alts and have the lights anx horns on the 1st battery leaving the amps only to the 2nd bank.
oh and when you get a high output alt it should tell you what wire to run. my 370amp mechman says right in the install instructions that i have to run 2 runs of 0g cca or bigger.
 
If you add a 2nd and third battery just connect them together as if they were one battery and go from there...  No need to complicate it.. You could probably start with just 2 batteries and see if it handles the load fine and only add a third if it doesn't. Your just looking at "key off" time you can run stuff...

Rodney
 
PromptCritical said:
700 cranking amps at 36 volts would have been... impressive...  :eek:

Naw 930 CCA at 36 volts, I could run a welder with that. LOL
 
Well to answer a few guys, starting in 2009 they offered a 730 CA battery which I have that option, and I would be getting either 2 or 3 of those

I am planning on running a lot of power. Full audio system, air compressor for on board air, train horns, and an absolute ton of lights. All of the light will be pulling a total of about 210 amps just in lights.

My main reason for getting big dual alternators and triple batteries is so that despite the fact that I will probably never turn all of my accessories on all at the same time, I will know that I can and have it all be safe and work well with enough power.

I am unsure of the onboard air setup I want, I do know the train horns I want but I also dont know what the audio setup I want will pull.
 
xoutofmyheadx said:
prompt, thats just dumb. you dont ever let an amp shut off due to low voltage that will kill an amp. not sure what kind of power hes running that he can even let it not run anyways cant be that much.

I was unaware of this.  Seems like a protective feature, so why would it hurt the amp?  I'll let him know.  He sold the Yukon this week anyway.  I believe the sub amp was a 1500W Power Acoustik and a 300W Alpine for the mains.  It would last for a couple hours if you didn't turn it up too loud.
 
09chevyavy said:
Well to answer a few guys, starting in 2009 they offered a 730 CA battery which I have that option, and I would be getting either 2 or 3 of those

I am planning on running a lot of power. Full audio system, air compressor for on board air, train horns, and an absolute ton of lights. All of the light will be pulling a total of about 210 amps just in lights.

My main reason for getting big dual alternators and triple batteries is so that despite the fact that I will probably never turn all of my accessories on all at the same time, I will know that I can and have it all be safe and work well with enough power.

I am unsure of the onboard air setup I want, I do know the train horns I want but I also dont know what the audio setup I want will pull.

CCA indicates how many amps the battery can deliver for 30 seconds at 0 degrees F. It's a short term, high power load rating for starting.  

What you should be more interested in is reserve capacity.  It's usually denoted by how many minutes the battery can support a draw of 25 amps.  

For instance, if you have a battery with a reserve capacity of 180 minutes, your lights alone will run it dead in 20 minutes.  That's assuming a linear function of load to capacity, but it's not linear.  The more current you pull, the less total energy you will be able to get out of the battery due to losses from internal resistance and other factors.  So lets call it 15 minutes.  Two batteries in parallel will probably last you ballpark 35 minutes at that load.  This will decrease as the battery ages.
 
Again, batteries do not produce power and you should insure your Alternator(s) can output more than your vehicle can ever use.

Running an alternator close to its maximum is always a bad idea because you can burn it up. They are not expecting to run 100% load all the time. They will get hot and thats not good.

Also about running your amps until they turn themselves off...  Very bad idea... It is there to protect the amp.. Not to be used as an indicator. You are better off having a voltage meter on the line so you know what your voltage is and never drop below 12volts. It is also hard on a battery to fully discharge it and on a battery like an Optima can make it unusable or kill your alternator. (Red tops for sure.. not sure on Yellow or blue)

Rodney

 
Ok then.  I'll recommend he get a low voltage disconnect then. Like this: http://www.colehersee.com/home/item/cat/206/48510/ That will let you run 2400W or so and cuts off at 12.1V.

BTW, I found this pretty awesome: http://www.colehersee.com/home/item/cat/211/48530/  It's a disconnect that works automatically.  Disconnect at 12.7V, reconnect at 13.2V.  No need to install any switches at all.
 
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