Jess’ car’s battery was completely dead when she went to use it last week. Completely dead meaning no lights or anything. I checked the voltage with my multimeter and found the battery could only provide a couple dozen millivolts, which I thought was unusual for most normal car battery problems (and the battery is only 4 months old). My thought was something was leaving a load on the battery even when the car was off. But since I know next to nothing about cars I didn’t put much stock in the idea.
We jumped it and it ran fine and the alternator was providing a charge voltage (tested with my multimeter), though I don’t have the ability to test how much current the alternator is providing. A couple days later, Jess goes to drive somewhere and, again, the battery is completely dead. So we jumped it and drove it to the shop.
I tell them what’s up, along with my thought that something is leaving a load on the battery. Their tests determine that the alternator is not performing correctly and replace it for somewhere north of $500 for parts and labor.
Yesterday, we pick up the car and it seems fine.
Today, Jess tries to drive it somewhere and it won’t start and the battery is low. It’s down to 9 volts and, after some finagling to get the alarm to be quiet, I was able to determine that one of the circuits (meaning the circuit running through a specific fuse) is pulling a load off the battery of several hundred milliamps to almost a full amp (but I can’t tell for sure how much since the battery is so low now).
I understand some load is normal (since you want things like your radio to keep its settings and your remote lock/unlock to work), but my reading suggests that up to maybe 50mA is acceptable.
So now I’m annoyed that I was probably right in my parasitic-load hypothesis and yet we paid for a new alternator. It very well may have needed an alternator, but that clearly wasn’t the _only_ problem, if it even was a problem, which I’m not convinced it was.
Would it be unreasonable to expect the shop to provide some kind of financial consideration when they fix the actual problem?