# Diesel Batteries



## FORD1 (May 15, 2007)

I have an 04 ford 6.0 that has about 67k miles . It has become extremly hard to start in the mornings or when it sits for a while (taking a good 5 sec to turn over).My question is what exactly are the 2 batteries for ? Does it require both batteries to start?And do I have to replace both batteries at once?I would think with 2 batteries they would last a little longer than this? Any help would be greatly appreciated. 
p.s 1 battery was extremly corroded so I cleaned all the corriosion off 
2nd battery clean as the day I bought the truck


----------



## bowed up (Apr 1, 2007)

The Two Batteries Are To Help Start The Truck Mostly, It Is Possible To Start It On One Though. After A While They Will Weaken A Bit In Cranking Amps, Nothing Unusual. Keep The Connections Clean And Spray With Some Corrosion Preventer. Gel Cells Will Prevent Corrosion, But Are Costly-200 Bucks For A Red Top Optima.


----------



## texasdave (Aug 15, 2005)

I have an 04 6.0. Recently, had two new batteries installed. Run it by Napa, O'Reilly's, Walmart, etc. have them test the batteries. One of mine was bad and the second one when I removed the positive clamp the post was broke. Mine started getting harder to start just like you described.


----------



## FORD1 (May 15, 2007)

TEXAS 
how much did it run for the batteries i am assuming you bought both,i figured they were high but 200.00 piece for the optima's ?ouch!!now you have me wandering because battery#1 looks like the day i bought the truck i am wandering if it is the same problem


----------



## TheGoose (Jan 22, 2006)

My understanding why diesels have two batteries is because of the amount of compression the starter motor has to overcome and the amount of current the glow plugs draw when starting. If you've ever bought a starter for a diesel truck you figure out real quick they are very expensive because they are high-torque.


----------



## wfishtx (Apr 10, 2006)

Its very common for diesels to go through batteries rather quickly and yes it does take both batteries to crank a diesel effectively. The motor will crank using one battery so long as it isn't cold, but I can promise you the one battery will not last long at all.

The best advice I can give you would be to take both batteries to Wal-Mart and purchase two new Everstarts. Make sure you spend the extra money and get the one that has a 3 year free replacement. I did this with my 96 PSD as soon as the original batteries went bad and I haven't bought new batteries since.

The Wal-Mart I frequent does not test batteries. If you bring in an old battery in, with the original receipt and it is within 3 years of purchase date they will automatically give you two free batteries (at least at the Wal-Mart at Katy Mills). 

These Wal-Mart batteries only last about two winters before they start going bad, so every other winter I go down and trade both of them in on new ones, no questions asked. Can't say they have truly gone bad, but as soon as they start heading that way, off they come and to Wal-Mart I go.

It was the best $150 I've spent in a long time.

Good Luck


----------



## sqwaby (Aug 4, 2005)

Had the same problem on our 01 PSD, found a loose neg cable at the terminal. As mentioned ck and clean all. Just to let you guys know we lost the alt. on a return from Fla. Found out you can go about 22mi with everything turned off before you loose the batteries.


----------



## GBFISHIN (Sep 14, 2007)

Batteries corrode on top because they have a leak, generally arround the post. Engine cranking speed is crucial to starting your vehicle. OEM batteries run about 120.00 a piece. They also have free towing during the five year warranty period. Regardless of what brand you choose, be sure the batteries are rated at atleast 750 cold cranking amps. Not to be confused with cranking amps, cca not ca. A battery with a 750 ca has a much lower cca rating.


----------



## boashna (May 28, 2004)

conumer report picked autzone bat- check the fluide level also if applicable, check charging system also ..


----------



## bwguardian (Aug 30, 2005)

boashna said:


> conumer report picked autzone bat- check the fluide level also if applicable, check charging system also ..


Been there, done that...the wifes Excursion diesel had a pair of their top of the line gold batteries under warranty; however, they would not warranty them because I was not the original purchaser. This is why I try to stay away from AutoZone. I put the Republic 1,000 amp batteries in it like the ones in my F-350 diesel for $150.00...and they warranty them no matter who shows up with them. Oh yea, the ones in my truck are 6 years old.


----------



## Supergas (Nov 30, 2004)

*Intersate Batteries.....*

Why mess with the retailer who probably does not really know much about batteries???

Go directly to your nearest Interstate Battery Store.. I buy a lot of batteries for both golf carts & vehicles & I will not go anywhere else.. Competitive prices as well as they can test the entire circuit not only the battery.... In addition to this, they can make up any cable you need on the spot....

I have used the Optima in the past, but in all my trucks I use the Interstate Megatron.... best buy out there in my humble opinion
Supergas


----------



## KID CREOLE (Oct 28, 2005)

Sometimes as one battery gets weak the other struggles, on a diesel if the engine is not spinning fast enough, there won't be enough heat to ignite the fuel. I run Interstates in both of my diesels and so far so good.

Try jumping your truck in the morning with another vehicle and see if it starts a little quicker.

Also, make sure your connections and the cables on the starter are good!


----------

