[fishacura]

So here's my story.

Bought our Odyssey in November. A couple days in we noticed a couple odd things (car would no longer beep when pushing lock button on remote...automatic doors would stop half way when opening/closing). Anyway, 3 days later it was dead. AAA came out and said "bad cell in battery" so dealership came and replaced it. OK great.

So 3 months later (a couple weeks ago) car stopped beeping again. Hmmmm. So I made an appt but never got that far, 2 days later car was dead again. Bad battery.

Dealer took it and started investigating. What they found was that a switch on the automatic doors was staying engaged and slowly drawing the battery. OK, they fixed it and replaced battery.

So here's what I am wondering. My understanding of car batteries (limited!) is that once you start the car, the battery charges. So if there was a draw because something was engaged when the car was not running, when you drove the car it would recharge the battery. So how can the battery have "gone bad" both times? Could the constant draw and recharge have caused these bad cells? What I would like to feel confident in is that what they fixed was in fact the root cause. Can this type of issue ruin a battery...twice?

 

[rdalley]

Your alternator provides power for the cars ignition, electronics etc. when it is running and just enough additional power to top off a healthy battery and keep it fully charged. If you have a parasitic draw that is killing a battery overnight or when it is off for any amount of time the alternator will not be able to charge the battery fully under normal use, short trips around town etc.

To answer your question, the constant draw on the battery can easily ruin it because the car's charging system is not capable of recharging a badly run down battery as you are driving.

 

[fishacura]

Thanks! interesting, that's exactly what he called it...a parasitic draw. GREAT!!!