Dieseldude4x4

Was in the NAPA dealer yesterday waiting to get the rig inspected. Was walking around looking at stuff and batteries. I remembered some of my John Deere tractors take two six volt batteries to make 12 volts. My 730 diesel takes four 6 volt batteries to get 24 volts for cranking. I understand this was done to increase the cranking amps through the use of the 6 volt batteries.<br><br>I was wondering, since the battery life with the dual battery set up in these trucks is only about three years and the right battery always goes bad first, would there be any advantage in going with the two 6 volt batteries to get 12 volts? The 6 volt batteries I was looking at were big whammer jammers rated at 1100 CCA each. I am curently running two 875 NAPA Legends that have worked real well so far. <br><br>Comments?

AlpineRAM

The 6 volt batteries I was looking at were big whammer jammers rated at 1100 CCA each. I am curently running two 875 NAPA Legends that have worked real well so far. <br><br>Comments?<br><br>Yes you'd actually loose CCA, now you've got 2*875 CCA = 1750 CCA ( parallel adds Amps leaves Volts )and with the 2 6V in series ( Adds Volts, Leaves Amps ) you'd just have 1100.<br><br>Also you'd have to re-wire your truck to get these buggers in series, and you'd need some big cable for doing so. Starter current would flow through the battery connecting cable<br><br>AlpineRAM

bulthisl

I've got tractors with 2- 6 volt set ups also.
I tried changing one to a 2 - 12 volt set up one time.

2 - 6's a little slower but will crank longer

2 - 12's cranks faster but runs out of steam a LOT quicker

2 - 12's work alot better on tractors

As I'm sure the 2- 6's is better for the CTD
Plus you won't have to rewire

JMHO


: Eddie : 8)

Haulin_in_Dixie

Honestly I think that the sixes are just a left over from the past. IMO Yesteryears technology on batteries was not so good. In 1956 Detroit went to 12 volts, trucks kept using the tried and proven sixes in pairs for 12 and quads for 24. Today it is rare to find a new vehicle using sixes. Freightliner went to three 12's in place of four sixes.<br><br>As a matter of fact Detroit is supposed to be going to 24 as the military did years ago. You can consider that also, the military used two 12's for the 24 instead of four sixes. You certainly would have no benefit from changing. Now for camper batteries that is a different story, two golf cart sixes work great and last forever for low amp long staying power.

DarrellB

DD, If you're worried about batteries I would go with a set of these after your Napa Legends die.

Optima Batteries

I just put new juice boxes in my 2500 last year and noticed the other day when cycling the grid heaters that the volt gauge was dipping a little lower than I like. When these batteries I got go I'm buying a set of Optimas. 8)

DB

HC

[quote author=dieseldude4x4 link=board=5;threadid=9137;start=0#87751 date=1041602253]
Comments?
[/quote]
My comment is that AlpineRam's answer is correct, unless you were intending to replace EACH 12 volt battery with TWO 6 volt batteries, for a total of 4 batteries. He's not just giving an opinion, he's applying the laws of physics to your question.

I second the motion for Optima's - don't go trying to re-engineer the electrical system, it's way more trouble and cost than just buying the best available 12 volt batteries you can get.

Lary Ellis (Top)

DD4x4, You got a big truck there so why not get 4 - 3 volt battries and really have fun ;D

AlpineRAM

I think it is very simple: The way the Dodge has it's electrical system is thought out using 2 12V batteries in parallel. The PCM does monitor several parameters like voltage, current and battery temperature to determine the optimal charging current. I wouldn't want to change anything in this system unless I intended to use the vehicle out of the specs that Dodge intended.
If you , for example change to batteries with a different capacity the charging system may get off whack.

The reason why most manufacturers tend to go to a single battery providing the voltage that is required for an application is that one of the main factors for efficiency and reliability is the resistance between cells that are used in series. Each cell of a lead acid battery delivers 2V. Put 6 in series and you have 12V. Take lets say 100 A ( 1200W) from this battery. You will see that there is a current of 100A on each bridge between the cells. So to be efficient it is vital to have little resistance between cells. Resistance of a given connection is a function of material, lenght and diameter(Area). Resistance is directly proportional to lenght and indirectly to diameter(Area). So we will look for a short and fat connection made of a material with a low resistance. Lets say lead as a material, put it all in a case and be happy.
Worst version would be to take 6 cells and spread them over the truck, get long flimsy vables between them.- Without a load you would see 12V- if you apply a load you would see a pressure drop because of the inner resistance of the system. (Before it goes up in smoke)

Just my2c

AlpineRAM

Dieseldude4x4

[quote author=SFtopSGT link=board=5;threadid=9137;start=0#88172 date=1041665534]<br>DD4x4, You got a big truck there so why not get 4 - 3 volt battries and really have fun ;D<br>[/quote]<br><br>Cool, never thought of that.

bulthisl

[quote author=bulthisl link=board=5;threadid=9137;start=0#87937 date=1041628418]<br>I've got tractors with 2- 6 volt set ups also.<br>I tried changing one to a 2 - 12 volt set up one time.<br><br>2 - 6's a little slower but will crank longer<br><br>2 - 12's cranks faster but runs out of steam a LOT quicker<br><br> 2 - 12's work alot better on tractors<br><br>As I'm sure the 2- 6's is better for the CTD<br>Plus you won't have to rewire <br><br>JMHO<br><br><br> : Eddie : 8)<br>[/quote]<br><br><br> Joel;<br>I just reread my post and I said it backwards. <br>I meant to say the 2 - 6's were better on the old tractor ( 806 IH ) and the 2 - 12's would be better on the CTD.<br>I wasn't trying to disagree with everyone else.<br>I just got my 6's &amp; 12's backwards. :<br>Sorry for the bad info. :-[<br><br>Guess I should have used the preview button. ;D<br><br> : Eddie : 8)

Dieseldude4x4

I sorta figured that Eddie. I knew what you meant.<br><br>While the system may be engineered, not well engineered at that, there is still some flaw there somewhere. This has happened to me on two different trucks. Has happened to a friend at work and another that is retired. The right battery goes bad and drains the left battery every time. My son is still running the left battery in his truck but the right one is stone dead. It is like the right battery never sees any appreciable load or charge and just dies after three years. Maybe three years is the life expectancy but why only one battery is still the mystery. Papa SmurF suggested swapping the batteries out every six months or so. That maybe a plan to get longer life. Or, maybe the charge and load need to be applied to a point closer to the center of where the two batteries come together. OR, just keep giving my son the left battery every three years.