My first battery (OEM) went bad in just 3 1/2 years, although I bought the truck used so who knows what may have gone on. So I bought a new, higher rated battery and for a while it started the thing up just as quick and 'tight' as you would expect. But then it started to act just like the previous one, where it will 'drag' a bit when starting, sort of like a cold-weather start. The thing is that it does this when it sits for a few days, not after it has been driven - so I don't think it is the alternator. If I put the charger on it right after it has been driven, it doen't charge at all (the meter is at maybe 1 or 2, and within a few seconds it is down to 0). If I wait 24 hours after it has been driven and put the charger on, it will go to 10 or 12 and charge for hours. The longer I wait, the more it needs to charge.

The truck always starts, even if I leave it sit for a week but you can tell it just doesn't have the cranking power it should, especially for this time of year. I have diconnected my invertor power cable from the battery and it makes no difference. There is nothing but the stock electronics hooked up or in use.

Any thoughts on a cause or best order of diagnostic steps?

ps - Just looked at my sig and thought I had better add:

As stated in the post, the inverter is disconnected, so the laptop is not an issue-
The center console LED is OFF-
The overhead LED only comes on with the headlights-
The iPOD only charges when the key is on-
The cellphone is NOT plugged into anything...

 

I've got the same problem. I replaced my battery last DEC and my truck is an 05. I recently picked up a beater car for work so the truck sit's alot. If it sits for 3 days or more I am lucky if it starts. I'm beginning to think it's that dam blinking red light on the dash.

 

The very FIRST thing I would do is disconnect the battery when you aren't going to use the vehicle for a few days and then reconnect when you go to use it . See how it starts then. You'll know if it's the battery or a drain in the vehicle. With a little test equipment and knowledge these things aren't that hard to diagnose but from long distance with not test equipment- a lot harder. There is a next step- but let's cover that 1 first. batteries are JUNK today compared to what they used to be. (you could buy a good one here and there, now it's very hard to buy one that will really last) and, yes there are batteries that are bad when you buy them, you just don't know it for a little while. Let us know what the results of the 1st. test are and we'll go from there.

 

The blinking light is LED and they use so little current it would take months to run the battery down with that. I think you'll have to look elsewhere for the culprit. Not only that, but if something is actually running the battery down (not just a bum battery), that will kill a battery in a short while. Starting batteries are designed to be kept at pretty much full charge and if they are frequently run down partially for whatever reason, they're going to have a very short life, I can assure you of that!

 

did you buy a batter with the same cranking amps as your old one? May have gotten a weaker battery?

 

OK, I am just waiting for a good time to disconnect the battery (when I won't be driving for a few days). The battery I purchased last time around is a Napa with a higher CCA rating than the OEM. Had it tested at Napa yesterday and his tester showed it as "Good Battery" with something like 867 CCA.

I'll post again when I have had a chance to let it sit unhooked for a few days...