short lived battery then no start

[scagle1]

Ok folks , am leaning towards new batteries but this past w/e went out to start the truck and got about 5 seconds of crank then click,click,click. Jumped it and ran fine the rest of the day , starting and all .Next morning same problem again..Hooked the charger up and let it run for about 3 hours and drove to work 9 hours later it starts fine but volt gauge looked a little lower than where it should have been when turned the key to start. I have no idea as to how old batteris are , and this is the first sign of any starting issues.Can hear fuel pump come on and shut off and the glow plug relay going off...I think...Sooo... Batteries or should I be chasing a short????? Thanks everyone.

[Southpaw]

Time for new batteries.
Make sure they are many CCA's as possible. MINIMUM 850CCA. Prefferable 1000CCA

[mrnecsteve]

Your problem could be caused by either condition you mentioned. Not enough data!
You could do well by investing in a hydrometer for a few bucks(little glass device with the floating balls) and a digital volt meter(decent quality...not a junk import)
First task is to measure the specific gravity of each cell if the batteries allow access.If the batteries have reached the end of their service life,you will see one or two cells that are significantly differant than the rest(usually near the posts)This condition can cause both batteries to not charge properly.
Second task is to measure the voltage of the batteries while under charge by the alternator.To do this ,you should start the truck and let it run for 10 minutes or so. Then With the headlights on (a simple load),measure the dc voltage at the batteries. It should read 13.6 to 14.3 volts. Deviations need to be considered but ultimately this is the desired running and charging battery voltage for lead acid batteries.
Third task, but harder to accomplish ,would be to measure the current of each battery ,both charging and discharging with an ammeter "in circuit " This device is relatively expensive. An inexpensive meter could ,however, be used to measure the drain current individually of each battery. (engine OFF,key off) From the sounds of it...if your problem is caused by a short,beware that a shorted diode in the alternator can be the cause of draining batteries. (Remember this for the situation that drives you crazy trying to find the cause of a drain while off problem)
CCA's : Dont get caught up in the more cca's are better advertising. It is only relevant within manufacturers (IF the minimum CCA has been met) It does not mean that if you buy 2000 cca batteries you will double your cranking power compared to 1000 cca batteries. This only applies to the particular manufacturers test load. Buying one manufacturers higher cca could be a situation of buying crap over quality.
Do you need to buy both batteries at the same time? No..it simply helps to guestimate the remaining battery life ,if you dont know the current status. There are ways to measure the health of a battery.It is simpler to replace both, but NOT "battery blasphemy" if you decide to take the risk.

[scagle1]

Thank you guy's just was not sure if i should hunt down a short . First vehicle i have bought in quite a few years that did not need batteries within the first two weeks of me buying it.

[Southpaw]

If they are the original batteries....Replace them...they are on borrowed time anyway.

and as far as CCA's...all I know is these PSD's take a lot of juice to turn over, and granted 850 does meet the min. req. but 1000CCA batteries crank over over just that much better and faster.

[mrnecsteve]

Originally Posted by Southpaw

If they are the original batteries....Replace them...they are on borrowed time anyway.

and as far as CCA's...all I know is these PSD's take a lot of juice to turn over, and granted 850 does meet the min. req. but 1000CCA batteries crank over over just that much better and faster.

Yep...I dont disagree.....BUT select a quality battery manufacturer first at minimum requirements,then if desired, increase the amperage capacity within that manufacturer. Or to put it another way,dont buy a battery strictly by the numbers. A quality battery at minmum ford specs is worth far more than a junker with good numbers only.

[Southpaw]

I'll agree with you on that one too.