Car would not start and the battery was completely dead. put in a new battery and on the 2nd day same thing. I have checked all electrical switches, the door is closed and the interior lites are not on. what could drain the battery completely?
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2008 Honda Odyssey
Question: electical problem
Answer #1ZeeTech March 14, 2011, 16:49Master
Either the alternator isn't charging or there is a parasitic load - one of the control modules won't go to "sleep mode".
I'd start with the charging system test and go from there.
Answer #2blazingirl67 March 14, 2011, 17:05Rookie
i was having a similar problem and i was convinced it was the alternator, but the battery light never came on. so i changed fuse #15 under the dash and sure enough everything went back to normal. apparantly hondas are common with this issue and a simple alternator fuse is the issue!!good luck i hope it works for you too!
patrick mannion from Greg Solow's Engine Room, March 14, 2011, 21:13Master
Great advice from both ZeeTech and blazinggirl67.
You may have some sort of battery draw that needs to be isolated and illuminated. You would need an amp meter disconnect one cable of the battery put your Amp meter in series with the battery cable that has been removed. Note the draw say for example 15 Amps, with the keys out of the ignition, doors closed driver's window down, start removing the fuse links and fuses one at a time until the voltage draw goes away to zero (or near zero about .02 to .05 Amps is about normal for a modern vehicle with a clock, stereo and other things that need "keep alive memory"). It is that circuit that is causing the electrical draw, then look at a wiring diagram, see what consumers are on that circuit and start to isolate each circuit to see which is the culprit. Modern cars have lots of computers and electronics that need constant battery even with the key off so parasitic draw of .2 Amps may be normal sometimes things stay "live for a minute or two after the door is closed so wait and look at the draw after a minute or two. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.