Battery drain

About 9 months ago I purchased a Duralast EFB battery for my truck. Haven’t had any issues until about a month ago when I noticed the truck a little sluggish to start. We drove it to the airport for a 1.5 week vacation so I took a jump pack to be safe. Good thing bc when we came back the battery was completely dead.

so since I’ve been back I haven’t had to jump it, but it definitely drops in voltage overnight or sitting long periods. Took it to Autozone and they tested it and said it tested good, but was only about 50%. So I’ve charged it up, and been trying to see if the alternator is bad, if there is some parasitic draw (lots of accessories on my truck) although I have a circuit breaker and blue sea fuse block that I’ve turned off and don’t see much of a difference.

Alternator seems to charge above 14V when truck is first turned on then drops to 13.5 or so.

I’ve been trying to isolate accessories to see if I can pin point the reason, but no luck.

Anyone else with suggestions?

 

was it doing it before ? could it be a bad battery to begin with if everything else checks out.
I always have issues with Costco batteries (lasting few months to 2 years) so maybe you got a bad Duralast.

 

Nope, no issues before but Inhad to replace the battery for some reason. I’m constantly adding and upgrading things so it’s hard to say what I’ve done since February that could be the issue. Or could be something has failed now.

I thought it was a bad battery as well, but I took the battery completely out of the truck, charged it up and let it sit in the house for about 7 hrs and the voltage was 12.85 in the AM. Which is a fully charged battery for AGM types.

 

AGM very sensitive to voltage even more so that a basic battery. I keep mine on tender all the time when it's not driven

 

I don’t think it’s actually an AGM. It’s EFB (Enhanced Flooded Battery) but it is sealed like AGM so it probably takes very similar voltages.

Im thinking of putting it on a battery tender, both my motorcycles are, but if there is a drain issue this would only be a band aid.

 

When it comes to battery healthy it’s not just voltage but pay attention to the amperage if it gets below 40% of the rated I would change out the battery. If you don’t drive your truck much take it out at least 1x a week and go for a drive on the freeway for at least 30 minutes to make sure you are getting a decent charge on the battery

 

After I had to jump it at the airport, I drove it home 3hrs. A day or two later, the battery was around 50%.

 

Whenever I have had a battery fully discharge I no longer trust it. I would suggest being in a mindset that the battery could fail again and possibly leave you stranded.

 

FWIW it might not be a solution but it looks EFB batteries need to be charged at higher voltages like AGM batteries so this thread can help you swap that fuse out. That'll definitely help.