I have a drain on my battery. This is my wife's car and is not used a whole lot. I put a trickle charge on it and it works fine. Until the other day my wife used it with no issue the day before and then the next day I decided to take it to work. It turned over and was running fine and then 4 miles down the road it slowed to 20 mph. I turned around and headed home. Once in the garage I turned her off and noted an engine fault display. I got out checked the battery it was at 12v and then turn her back over. The alternator was reading 14v.

Any thoughts about this are helpful. I think perhaps my battery is shot? What drains the battery over time?

 

New battery. Alternator running will show 13.8 - 14.4 volts. Turn on all the lights, wiper, AC, and it still should be above 13.2 (under load). Won't hold up voltage under running load means alternator diode may be bad. Battery just sitting there overnight should be 12.6 ish with truck not running. Turn on all things that will run without truck cranked and should still be well above 11 volts (under load).

Battery rated for 5 years may last 3 years. LR 3 has lots of electrical parts that go after battery capacity.

There was that old lady in Orlando area with a Ford Falcon at 500,000 miles plus and 19 JC Penny lifetime batteries....

 

No wonder JC Penny has financial problems.

 

Other than a fuse, the battery is one of the cheaper parts of the electrical system.