Dual Batteries

tjkj2002 · **Posted:** Sun Aug 09, 2009 11:48 pm

stumpjumper_09 wrote:

2 batteries in parellel will yield 12vdc. 2 batteries in series will yield 24vdc

Yes,but do you need 2 batteries? Since the battery is primarily only used to power the starter(99.9% or the time it's only use).

Quote:

How about something even more ultra rare where you realize that your way isn't the only or best.

It's not my way,if 2 batteries was better then every vehicle would come that way and not just diesel trucks.

cmohr · **Posted:** Mon Aug 10, 2009 1:12 am

Dont get confused between "2 Battery" systems and "Duel battery " systems.

A vehicle requiring 2 batteries is generally a bigger engine so much more cranking power is needed to start vehicle. Both batteries are the same, primary cranking batteries in line (and in some cases IE diesels as a 24 volt so a starter motor with more torque can be used) for prolonged cranking and starting. Both batteries are used for starting and running the electrics in the vehicle at all times.

The "Duel Battery" system is quite different. The primary Battery is a vehicles standard cranking battery used for starting the car, the 2nd battery is a "Deep cycle" battery (can be 20amp Hr right up to 120 amp Hr and beyond - just depends how much space you have for it) The 2ndary battery is not for starting the vehicle it is for running electrics, like Fridges, winches, spotlights ect ect. Once the car has started the alterator recharges the primary battery, then, the "Duel Battery" managment system switches the charging over to the Deep cycle battery to charge it. This means your main cranking battery will always be at full charge to start the car, and the deep cycle batteries can run electics for 10 - 20- 100 Hrs. Beauty of this system is for camping you can run lights all night, a fridge radios, and you will still happily start the car in the morning, also, for 4wd, esp at night, you can crawl along, run all your lights, winch radios and not flatten your primary battery.. Plus IF your Primary battery does die, you can Start the car with the 2ndary - its just not recommended - but is OK to so in times of need.

Two completey different systems, each for its own purposes.

JL Rockies · **Posted:** Mon Aug 10, 2009 9:33 am

Jeepjeepster wrote:

JL Rockies wrote:

Great... cause if he wants more power, a dual batt system will yield less power than he has now...... That's why......

Say what? Maybe he has things that he is wanting to run while the Jeep is off. Thats the only reason I can ever see that you would need an extra battery.

I agree.... that's why I wanted to know why... but it's not "more power".

JL Rockies · **Posted:** Mon Aug 10, 2009 9:38 am

stumpjumper_09 wrote:

REALLY? Is that why large trucks run multiple batteries? Chevy put 2 batteries in the K3500 for the tow package and the plow packages. In car audio competition we have run up to 4 batteries in one car to have enough stored energy to run high powered DC Amps.

No, that's not why large trucks have multiple batteries... and in car audio competitions... If he's going up to the arctic circle to compete in car audio competitions with his engine off, then OK.... but he still has less power.....

JL Rockies · **Posted:** Mon Aug 10, 2009 9:40 am

stumpjumper_09 wrote:

The truck that i was thinking of was my 95 k3500 4x4 with 454. 12 volt system same as kj.

OK then it still has no "more power" than the single batt system. Both are 12V systems.

JL Rockies · **Posted:** Mon Aug 10, 2009 9:43 am

stumpjumper_09 wrote:

2 batteries in parellel will yield 12vdc. 2 batteries in series will yield 24vdc

Yes and the series batts will damage pretty much everything electrical in the 12V system..... And since electrons need a difference in potential to travel, a 12V alternator can't charge a 24V Batt.

JL Rockies · **Posted:** Mon Aug 10, 2009 9:45 am

stumpjumper_09 wrote:

How about something even more ultra rare where you realize that your way isn't the only or best.

Utra-rare like the laws of physics which govern the whole universe cease to apply in your vehicle?

JL Rockies · **Posted:** Mon Aug 10, 2009 10:11 am

I'm going to splain it one more time (I pretty much posted this more times that I can remember) before a MOD moves this to electrical...

All power to operate a vehicle comes from the alternator (all power to move a speaker does also). Once the Batt provides juice to start a vehicle it immediately becomes a load on the alternator as does the electrical system and any accessories. If you add another battery, you add an additional load and since the alternator can't generate "more power", it's output is now split again and everyones share is reduced (like a Fed program).

Keep in mind that an isolator system isn't perfect either. There is loss through the isolator itself (reducing the charge voltage) and since the "extra" battery is still connected to the circuit via the chassis (negative return for the whole electrical system) it can still discharge if the main battery discharges as well. Electrons have a nasty habit of traveling to a positive charge when there's a difference of potential. Since there's no isolator on the ground wire, and electrons seek balance you can see the potential for extra batt drainage when you least expect it.

Ohm's Law..... you betta recognize... chilly willy.

stumpjumper_09 · **Posted:** Mon Aug 10, 2009 3:25 pm

You are truely making my brain hurt. If I was going to be sitting in the middle of the artic circle and had my choice between 1-660cca battery on tap or 2 I'm gonna go with 2. 12v into an electrical system is 12v. If tjkj can run a 1200+cca battery and not cause damage how could it hurt mine. Pulling from 2 power sources wired in parellel still gives 12v but twice the reserve power and any draw will pull evenly from both sources. Also am I blind or have i already established the fact that the truck in question was a GAS POWERED 12VDC 454 If you can't understand the idea of reserve power you need to leave your gas cans at home and stop talking crap.

KJ 119 · **Posted:** Mon Aug 10, 2009 7:15 pm

R

M

F

E

You guys are in denial about the benefits of a dual battery setup.

Put in the same situation,out in the middle of nowhere,with nobody around:
Main battery is DEAD)you are screwed.I switch my perko to "All"and I'm off to the races.

Would you rather be the guy who's screwed,or the guy who's off to the next fishing hole?
icefisher45,I suggest you go with a dual,so I'm not the only one reaping the benefits.And to
prove these guys wrong,once again.Not in science fact,but in the fact that I am running
a great system.

BUT......................What do I know,I gots a flawed system yo. :roll:

That works SUPERB.

http://www.lostjeeps.com/forum/phpBB3/vie ... 8&start=20

KJ 119 · **Posted:** Mon Aug 10, 2009 7:21 pm

Oh yea,add 40amp inline fuses at each battery.Almost forgot. :roll:

And swap yer red for a yellow if you've got a winch.

cmohr · **Posted:** Mon Aug 10, 2009 8:15 pm

Oh... Another option is a Jump Start Battery Pack... I have a 20AmpHr under the Passagers seat, plug into the lighter socket to charge it, can run a fridge, and has Jump start leads attached to start the car in emergency... Plus its portable. (First thing I bought when I got an Auto Transmission)

durangotang · **Posted:** Mon Aug 10, 2009 8:20 pm

A jump box kept in your rig will give you the extra safety without the expense or potential draw on your system.

As for being up north, don't sweat it. I lived near the arctic circle most of my life and never had a rig with 2 batteries. One good battery will be more than sufficient unless you want to run lots of accessories with the engine off.

LIV42DY · **Posted:** Mon Aug 10, 2009 8:35 pm

One battery is good enough on the KJ, if you are concern running down a bit of the power when you are standing still, Go Solar Panel, 15/ 20 watt roll away and your set.

Boiler · **Posted:** Mon Aug 10, 2009 9:05 pm

Two twelve volt batteries connected in series would yeild more cold cranking amps, and by extension, power. 12 volt system...Power (Watts) equal volts x amps...more amps...hence, more power/watts. Pretty simple.

Now how it works with the alternator I have no clue. But the machines I design are electric vehicles. A big electric motor usually powers a hydraulic pump which powers the wheels, lift cylinders, rotation motors, etc. When we have a high pressure and a high flow, those amp requirements increase. What do you do? Add batteries.

I'm not arguing for or against dual batteries in a KJ. I just don't see how two batteries in parallel can be seen as NOT delivering more potential power. I like the idea of the backup battery with a disconnect myself.

stumpjumper_09 · **Posted:** Mon Aug 10, 2009 9:10 pm

Finally the right man to explain............

Thanks Boiler

Boiler · **Posted:** Mon Aug 10, 2009 9:23 pm

Well, I don't know everything...like how it behaves in an automotive setup. I just know that more batts in parallel = more CCA. We usually use deep cycle batteries and power motors with them, and our battery suppliers list it as a typical option/method.

tjkj2002 wrote:

stumpjumper_09 wrote:

How about something even more ultra rare where you realize that your way isn't the only or best.

It's not my way,if 2 batteries was better then every vehicle would come that way and not just diesel trucks.

I think we've established on multiple occasions that the auto companies will supply the cheapest possible adequate solution. Though it may or may not be better, not being the production standard isn't a very sound argument.

tomsjeep · **Posted:** Mon Aug 10, 2009 10:41 pm

Boiler, thanks... I've been watching this go back and forth... for solar power systems, it's always batteries stacked, both in series and parallel, to achieve the desired voltage plus enough power (amps) to get through the night...
I can see how one could argue that the alernator supplies all the power to the system... and with a dual battery system (presuming you could find a place for battery number two) your alternator is going to struggle to keep them charged. But more than once I've had alternators fry and drove around on battery power alone (until the battery was drained).
But the battery and alternator/charge system work together. Boosting battery storage amps and having a larger output alternator together is necessary to get a system to work for a larger current draw.
Just my inept 2 cents.

icarl · **Posted:** Mon Aug 10, 2009 11:40 pm

icefisher45 wrote:

Thinking of going thru Canada to the Arctic circle.

You mean you're going to Alaska right? That's where most Americans eventually go.

I live in NW Alberta so I see many RV's with US plates driving through all the time. There is a highway all the way to Alaska. There was also a route built through the NWT (Canada) and was built by the US Army during the WWII as a train route to bring supplies to army troops stationed up there. I actually bought a book on it and it has pictures of old military jeeps trying to drive through some pretty nasty stuff. If you are truly going to the arctic think bush planes, snowmobiles, dog sleds, Eskimos, and polar bears.

durangotang · **Posted:** Mon Aug 10, 2009 11:46 pm

I drove a GTO north of the arctic circle several times... you'll be fine

Dual Batteries

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