Dual battery question

[Rubberdown]

Hey folks,
I read up on a whole lot of dual battery information and looked at a whole lot of wiring diagrams. My goal with the dual battery system is to be able to start the car after running, for an extended period of time, a bunch of auxiliary crap like the radio with the doors open while I'm fishing, some led lights (which I don't have) to illuminate under the awning (which I don't have), on the roof rack (which I don't have), and to run the fridge, (which I don't have). Also wanted to add a winch (don't have that either), and some led light bars, (don't have that either).

From what I see the dual battery setups run an additional power circuit which you add, and only power that circuit. So while I could run the lights, fridge, etc.. And that would drain down a second battery, any stock stuff that was running (like the radio, or internal lights) would drain down the main battery. Is that a correct summation of how things work?

 

[limamike]

Hey folks,
I read up on a whole lot of dual battery information and looked at a whole lot of wiring diagrams. My goal with the dual battery system is to be able to start the car after running, for an extended period of time, a bunch of auxiliary crap like the radio with the doors open while I'm fishing, some led lights (which I don't have) to illuminate under the awning (which I don't have), on the roof rack (which I don't have), and to run the fridge, (which I don't have). Also wanted to add a winch (don't have that either), and some led light bars, (don't have that either).

From what I see the dual battery setups run an additional power circuit which you add, and only power that circuit. So while I could run the lights, fridge, etc.. And that would drain down a second battery, any stock stuff that was running (like the radio, or internal lights) would drain down the main battery. Is that a correct summation of how things work?

Yes, whatever you have wired to either battery will run the battery down when the engine is not running.

 

[Rubberdown]

So how do you wire up the batteries so there it quits while there is enough juice left to start the car? I was hoping to discharge a "accessory battery" and leave the main battery to charge start the car. Is there some battery isolation system or something that does that with dual batteries? I typed in dual battery isolation and looked at that but that doesn't seem to run both battery circuits.

I guess I am saying is there one dual battery, isolation, blah blah system that people use to accomplish such a thing?

 

[limamike]

So how do you wire up the batteries so there it quits while there is enough juice left to start the car? I was hoping to discharge a "accessory battery" and leave the main battery to charge start the car. Is there some battery isolation system or something that does that with dual batteries? I typed in dual battery isolation and looked at that but that doesn't seem to run both battery circuits.

I guess I am saying is there one dual battery, isolation, blah blah system that people use to accomplish such a thing?

The IBS Dual Battery Management System is a good solution. It does not automatically cut-off voltage to the circuit, but it sounds an alarm when voltage drops below a certain level. The IBS system allows you to both isolate and link the batteries at will or through its own logic. There are other systems out there as well (National Luna, Kodiak, etc) that provide some features above a standard switched solenoid system, but I run the IBS, so I can only speak to that system.

 

[Antman]

So how do you wire up the batteries so there it quits while there is enough juice left to start the car? I was hoping to discharge a "accessory battery" and leave the main battery to charge start the car. Is there some battery isolation system or something that does that with dual batteries? I typed in dual battery isolation and looked at that but that doesn't seem to run both battery circuits.

I guess I am saying is there one dual battery, isolation, blah blah system that people use to accomplish such a thing?

When I was researching dual battery setups I had the same question. Ultimately, I decided to set mine up a little bit different than most.

My main battery is a big dual purpose 27 group battery. Dual purpose meaning it is a starting battery, and a deep cycle with a nice fat reserve capacity of 160 minutes.


Dual Purpose Battery

You can't fit a battery this big anywhere else in the spaces available under the hood. I moved the stock battery over in front of the airbox as my backup-only battery. My thoughts are this. My main battery has a pretty substantial capacity which will run my accessories at least twice as long as my stock battery did. In short, my setup will drain the main battery but leave a backup ONLY for starting the vehicle.

If I kill the main battery it won't be damaged because it's deep cycle, and I can flip a switch to start off the auxiliary (stock) battery.

The way I wired my switch I can connect or isolate both batteries at anytime, or leave the system on "automatic" which connects them whenever the truck is running and isolates them when it's off.

Best of all- it was cheap, simple and it works perfectly.

I just tested it this past week. I left ALL my lights on, blasted the radio and left my thermo-electric cooler plugged all day while I detailed the interior. The engine would not start with the main battery- flipped the switch and it started right up. Gotta love the piece of mind this gives ya!

Here's my setup:

ANTMAN'S DUAL BATTERY SETUP

 

[Rubberdown]

So just so I'm 100% on your systems functionality Antman,

When the switch is in auto:
Both batteries are charging and discharging and are tied together 100% of the time.

When switch is in Manual:
System is running strictly off your main battery. When this discharges 100% you flip the switch back to auto and it will start the car off your second battery. You let the car run and it recharges your main battery to 100%


Does this sound correct?

 

[Antman]

So just so I'm 100% on your systems functionality Antman,

When the switch is in auto:
Both batteries are charging and discharging and are tied together 100% of the time.

When switch is in Manual:
System is running strictly off your main battery. When this discharges 100% you flip the switch back to auto and it will start the car off your second battery. You let the car run and it recharges your main battery to 100%


Does this sound correct?

No.

When the switch is in AUTO the batteries are connected only when the ignition is switched on. If the truck is running, they will be charging. If the ignition is on but the truck isn't running (think playing the radio with the truck off) they will be connected together.

When the switch is in MANUAL both batteries are connected no matter what. Truck running, truck off, doesn't matter. This allows you to self-jumpstart.

When the switch is in the center position (OFF) both batteries are always separated. Basically the OFF position will allow you to charge only the main battery, or keep the batteries separated while the ignition is on(truck running or not running). This allows me to listen to the stereo without draining the backup battery.

 

[hrod79]

So [MENTION=65614]Antman[/MENTION], with the set up the way you have it figured out you have all the accessories running off the Main (deep cell battery) and Auxillary battery is basically a standby for when it is needed to start the truck?

 

[Antman]

So [MENTION=65614]Antman[/MENTION], with the set up the way you have it figured out you have all the accessories running off the Main (deep cell battery) and Auxillary battery is basically a standby for when it is needed to start the truck?

That is correct.

You can still connect or separate the batteries anytime you wish though.

 

[Rubberdown]

Ooooo I didn't realize there was an off position on your switch. This sounds like what I am after. And it looks to be fairly cheap which is definitely a plus.

 

[eddiebx]

No.

When the switch is in AUTO the batteries are connected only when the ignition is switched on. If the truck is running, they will be charging. If the ignition is on but the truck isn't running (think playing the radio with the truck off) they will be connected together.

When the switch is in MANUAL both batteries are connected no matter what. Truck running, truck off, doesn't matter. This allows you to self-jumpstart.

When the switch is in the center position (OFF) both batteries are always separated. Basically the OFF position will allow you to charge only the main battery, or keep the batteries separated while the ignition is on(truck running or not running). This allows me to listen to the stereo without draining the backup battery.

 

[jangoforhire]