Cold start, Battery problem?

[MtPaul401]

I'm having problems cold starting my 99 F350. If the temp gets below 30 or so I get maybe 3-4 tries then the batteries don't have enough juice to turn the starter.
I replaced the alternator in Oct, and they seem to charge when the truck is running, but sure don;t seem to hold the charge. How many attempts should I be able to get out of a good pair of batteries?

Does this sound like bad batteries? Please reply soon, I may need to drive my rig in the cold since my gasser is sick and is going into the shop soon.

Thanks!

[vitalidle]

Sounds like it could be bad batteries. Get them load tested. Are they originals?

[BioStroker]

I only get 3-4 tries, and that's all the battery's got. I had both batteries tested and they both tested fine. Of course the 3-4 tries is when it's 0 degrees or into the negatives!

[MtPaul401]

I think the batteries are original, can't see a sticker on them to indicate date though. They're Motorcraft batteries.

[vitalidle]

If its taking you that many tries to get your motor started you probobly should check the glow plug relay and the glow plugs. Sounds like it could be originals. Get them load tested and go from there

[MtPaul401]

I just pulled them out, the sticker is 4/06. Hmmm, maybe the bad alternator killed them?
I'll get them checked and go from there. Looks like I may have to re-read the posts about checking and testing the gp's and gpr.

[vitalidle]

Hmm well I would charge them up tonight then load test them to make sure. Then go from there.

[MtPaul401]

Think I may have solved the problem. Took the batteries in, one was showing still 775 amps, the other was totally dead.
2 new NAPA Legen batteries later, put them in and cranked it over. I was crossing my fingers, at 23 degrees and not having been run for 2 days I was not optimistic.
Cycled the plugs 2 times, 1st time it fired right up! I had no idea the starter was supposed to sound that fast.
I'm still going to check the GPR and GP's since I bought a volt meter as well.

Thanks for the help!

[vitalidle]

Good deal! Your one bad battery was dragging the other one down with it