Dual batteries. Why do we need it VS a larger high capacity one in stock location?

[gshadow325]

Being relatively new to the truck world but not new to 12 volt and the need for more batteries. My experience with the need for dual batteries would be for more power for a large car stereo system.

In a offroad/truck application, why do we need dual batteries? I see this alot and just want to understand why people do it. I did the biggest highest capacity battery that I could stuff into the oem location and it was little more than double the oem specs.

Skool me on why would we need dual batteries?

 

[EHNWI]

I too would like to know. Does it have to do with running a winch, or possibly an on-board compressor? I know the ARB fridge many use probably is a good excuse alone to get another battery. Also, I have seen in build threads like Dawg4Runner where he has outlets in the back which is awesome.

 

[BigNuge]

Dual batteries. Why do we need it VS a larger high capacity one in stock loca...

Frequent winch use....high auxiliary lights/loads.

Ver comfortable safety factor while WAY in the woods/desert....

Suppose there are lots of reasons.

 

[gshadow325]

Ok, fair enough. Why can't a high capacity deep cycle battery do vs two batteries? With two a larger alternator would be nice too then right?

 

[nevada]

the 2nd battery can act as a 2nd VEHICLE. if something happens, leave the lights/key/stereo/etc ON, and kill the battery.

 

[BlackWorksInc]

Here's why I am planning for a dual battery system:

~Modern vehicles use the battery to "smooth" out voltage irregularities and create a more stable voltage that is highly critical to sensors, modules, and other sensitive components in an OBDII CAN vehicle. As such, I want high voltage/amperage drawing equipment on a separate circuit that cannot accidentally cause damaging voltage spikes in the vehicle's critical systems.

~Running a second battery allows me not to have to worry if I accidentally drain the battery too low to start the vehicle.

~A second battery allows me to create a closed circuit (aside from charging voltage from the alternator) for all high amperage components (the on-board air compressor I am looking at draws a peak 80amps when running) and maintain a relatively simple wiring layout without having to worry about tying into the factory fuses and such (I'm a big "make it look factory" kind of mindset)

~I can use a second deep cycle battery to provide an engine off battery source without worrying about killing my car (I would recommend this be done in conjunction with a high-output alternator and to not drop the battery voltage critically as Alternators are not meant to charge a completely drained battery)

~A second battery can be used to jump start the primary battery and/or be switched to use as the primary battery

~A second battery can be used with a pair of strong jumper cables as a sacrificial power source for stick welding serious damage on the trail (not really intended, but if you ever need it its there, some Heep guys and serious expedition guys have told me stories of how that's helped them in the past)

In my case I need it for Reliability, Voltage/Amperage Control and Isolation, and Redundancy

In some cases, some people have a need for a potential 2000CCA system (I know 24V systems on commercial trucks tend to have a couple batteries for just one actual vehicle) and you really can't buy a 2000CCA battery I think?

 

[gshadow325]

In Car audio there are such batteries. http://stingerelectronics.com/productDetails.aspx?ProductId=133&CategoryID=4
The spp2150 = 2150 cca battery

So guys do a dual battery setup primarily for redundancy? High current stuff like compressors can be run from a high capacity battery right?

Is there a real need to run 12 volt stuff with out the engine running? Wouldn't a generator be better then?

 

[ebg18t]

I run dual batteries right now.

Battery 1 starts the truck and runs the OEM electronics. I also have a BlueSea fuse box connected that has: HAM radio, Led Light bar, Led D2 lights and ARB Compressor. This battery also has my TJM winch directly connected.

Battery 2 has my Engel MT45 fridge on 10g wiring and a set of separate marine 12v plugs in the rear panels.

Battery Charging and separation is controlled by a BlueSea ACR.

Overall works excellent. I prefer to have my fridge separated on its own battery so I always have a dedicated starting battery.

Both batteries are Deka/East Penn AGM's.

 

[Offroader5]

Dual battery in terms of those using it in an off road capacity is for redundancy in lieu of only adding capacity or amp hours. Usually this includes some type of manual or electronic isolation circuitry to isolate the secondary battery from the primary so it does not get drained. I'll be doing one of these setups soon.

When I wire mine, the second battery will be what all the aux items (non-OEM lighting, added fuse panels, fridge, etc..) will be connected to. This leaves the primary battery to be just that, the primary systems, ie..OEM setup. At any time one of aux systems drains the secondary battery, it still leaves the primary battery isolated and you can still start the truck. Once started, the secondary battery begins to recharge. Also some of the dual kits allow the "summing" of both batteries for the higher capacity for use in winching or other high draw needs.

BTW, it is most often suggested in dual isolated setups, that the winch stay wired to the primary battery. Then if you need the added capacity, you can switch the system to the summing capability.

If only looking for more capacity (like many installs for car audio), the batteries are simply connected in parallel to achieve a higher overall capacity. Same could be done with one large capacity battery, but normally you can get more capacity for the money by running two lesser priced lower capacity batteries in parallel vs. buying a very large capacity specialized single battery that will cost a good chunk of cash. This non-isolated setup could still result in not being able to start your truck since both batteries could be drained.

In my opinion, the only way to do dual batteries is by using an isolation system.

 

[Offroader5]

Is there a real need to run 12 volt stuff with out the engine running? Wouldn't a generator be better then?

Campers and wheelers (especially overland or expedition travelers) will have numerous items that they'd run with the vehicle off. Normally though if they will be doing it a lot, they will also invest in solar. Portable fridges, laptops, cameras, aux lighting, communications, etc..are all items that they could have running all the time. Very few of the overland guys, gals, couples I know have generators. We are usually more interested in the peacefulness and solitude that comes with where we are and would cringe at a generator running in the background to keep our goodies running.

 

[ddnww]

Here's why I am planning for a dual battery system:

~Modern vehicles use the battery to "smooth" out voltage irregularities and create a more stable voltage that is highly critical to sensors, modules, and other sensitive components in an OBDII CAN vehicle. As such, I want high voltage/amperage drawing equipment on a separate circuit that cannot accidentally cause damaging voltage spikes in the vehicle's critical systems.

~Running a second battery allows me not to have to worry if I accidentally drain the battery too low to start the vehicle.

~A second battery allows me to create a closed circuit (aside from charging voltage from the alternator) for all high amperage components (the on-board air compressor I am looking at draws a peak 80amps when running) and maintain a relatively simple wiring layout without having to worry about tying into the factory fuses and such (I'm a big "make it look factory" kind of mindset)

~I can use a second deep cycle battery to provide an engine off battery source without worrying about killing my car (I would recommend this be done in conjunction with a high-output alternator and to not drop the battery voltage critically as Alternators are not meant to charge a completely drained battery)

~A second battery can be used to jump start the primary battery and/or be switched to use as the primary battery

~A second battery can be used with a pair of strong jumper cables as a sacrificial power source for stick welding serious damage on the trail (not really intended, but if you ever need it its there, some Heep guys and serious expedition guys have told me stories of how that's helped them in the past)

In my case I need it for Reliability, Voltage/Amperage Control and Isolation, and Redundancy

In some cases, some people have a need for a potential 2000CCA system (I know 24V systems on commercial trucks tend to have a couple batteries for just one actual vehicle) and you really can't buy a 2000CCA battery I think?

ding ding, and yes you can buymore than a2000cca battery

 

[gshadow325]

OK! thanks for all the usefull info

Now i learned something today and i can get out of my isolation booth!!

Taking all this info, appling it to my car stereo knowledge.

I would do something like this then.

-Dual Stinger SPP1700 Batteries (have one of the beast now in OEM location.
*1 in OEM spot
*2 in hidden void that is behind the seat but in front of the 2nd tier for the rear cargo shelf
-Stinger SPG35 High Current Relay.
-High Current 210AMP Alternator Direct drop in.
-Stinger 4 ga Power Wire
-Stinger Battery Interconnects
-Replace All power and ground wires going to and from battery

Purpose of the high current relay it will only come on when the vehicle is on. When vehicle is off the second battery is cut off from the vehicle side.

Can some of you guys post info and pictures of your setups?

 

[KidVermicious]

Being relatively new to the truck world but not new to 12 volt and the need for more batteries. My experience with the need for dual batteries would be for more power for a large car stereo system.

In a offroad/truck application, why do we need dual batteries? I see this alot and just want to understand why people do it. I did the biggest highest capacity battery that I could stuff into the oem location and it was little more than double the oem specs.

Skool me on why would we need dual batteries?

You don't need dual batteries. Very very few people actually need dual batteries. Lots of people, including me, want dual batteries because they provide a) more battery capacity for winching/lights/fridge/whatever (which you could do with a larger battery), b) the ability to run separate 12v systems in isolation (which I suppose you could do with a single battery and the right setup) and c) redundancy in case of a battery failure (which you can't do with just one larger battery no matter what).

If you aren't out abusing your truck and battery in the middle of nowhere to the point that you need that redundancy, then a single higher capacity battery will probably serve you just fine.

 

[gshadow325]

You don't need dual batteries. Very very few people actually need dual batteries. Lots of people, including me, want dual batteries because they provide a) more battery capacity for winching/lights/fridge/whatever (which you could do with a larger battery) and b) redundancy in case of a battery failure (which you can't do with a larger battery).

If you aren't out abusing your truck and battery in the middle of nowhere to the point that you need that redundancy, then a single higher capacity battery will probably serve you just fine.

thats true, very true. My high capacity Stingers in all my cars have served me well in all the years. The one in my wagon gets beaten up ALL the time from my dual ViAir 480C compressors that keep pumping up my 5 gallon airtank.....like to use my train horns LoL

 

[riceandpho]

i run dual sears diehard pm-1, its because i have alot of audio gear(4 amps), i need to keep my system stable at full tilt, it can drain my voltage to 12.6 at idle whem im really hard. also i can listen to my radio longer and dont have to worry about not being able to start the car, i wire my 2 amps to stay on with radio and other 2 to a switch for this purpose. also with 2 fat batteries, i can jump any car back up with ease.

 

[daka320]

Anyone who lives in the deserts of the southwest knows how heat can kill a battery. We have to replace ours about every other year. So, if we are on a trip away from civilization we take along the battery from our popup just-in-case. Cheap insurance!

 

[nevada]

You don't need dual batteries. Very very few people actually need dual batteries. Lots of people, including me, want dual batteries because they provide a) more battery capacity for winching/lights/fridge/whatever (which you could do with a larger battery), b) the ability to run separate 12v systems in isolation (which I suppose you could do with a single battery and the right setup) and c) redundancy in case of a battery failure (which you can't do with just one larger battery no matter what).

If you aren't out abusing your truck and battery in the middle of nowhere to the point that you need that redundancy, then a single higher capacity battery will probably serve you just fine.

agreed.

even wheeling, and winching a lot, I ran a single battery, and stock alternator for years. but, then after one night trip...
one LONG night trip. we had one disabled jeep strapped to my bumper, and I had to winch us both up a steep muddy hill.
with the lights on, the engine fan, running the heater, and the winch working that hard...

I was holding the rpms at about 3k, to get enough juice, and even then, while winching, it would literally drop the power down far enough that the engine would start sputtering and missing. there wasn't enough power to run the ignition.

that was the last trip with a single battery.
upgraded to duals, and a 140 amp alternator.

 

[ddnww]

Now i learned something today and i can get out of my isolation booth!!

Taking all this info, appling it to my car stereo knowledge.

I would do something like this then.

-Dual Stinger SPP1700 Batteries (have one of the beast now in OEM location.
*1 in OEM spot
*2 in hidden void that is behind the seat but in front of the 2nd tier for the rear cargo shelf
-Stinger SPG35 High Current Relay.
-High Current 210AMP Alternator Direct drop in.
-Stinger 4 ga Power Wire
-Stinger Battery Interconnects
-Replace All power and ground wires going to and from battery

Purpose of the high current relay it will only come on when the vehicle is on. When vehicle is off the second battery is cut off from the vehicle side.

Can some of you guys post info and pictures of your setups?

People have done this in car audio for many years, my Monte Carlo had dual batteries, that way can play music all day at car shows without draining main battery, both charged by alt, but only one drained by stereo.

Make sure you upgrade the big three, but I'm sure you already know that