Honda Car Forum

Hopefully someone out there can help me on this one.

Starting last week, I started having problems starting my 2000 Honda
Accord EX. The engine would not turn over because the battery was too
low (Lights would dim when trying to start etc). So I had a buddy of
mine give me a jump and drove home. I then put a volt meter on the
battery to find I had 12.X volts on the battery. The next morning
(after a VERY cold night in the garage) the car battery was all but
dead, the door locks wouldn't even unlock from the key fob. So I put
the battery on a charger overnight so that I could take the car into
the shop the next morning. The Honda Dealership shop replaced the
batter (a 9 month old battery at the time) to no avail; two days later
the car wouldn't start again. BTW I also have a brand new alternator
on the car as well (as of 5/2005). So off to the shop I go again (this
time I did not have the volt meter at hand as I was at work, but I am
sure the volt meter would have shown the battery was drained). The
shop kept the car for 2.5 days and even left it out in the cold only to
find no draw on the battery and the car started like a charm every
time. They even thought it might be a problem with the starter but
admitted it was unlikely the culprit. So I took the car home knowing
it would most likely happen again, but this time I would make sure to
keep the volt meter handy. As soon as I got the car home I put the
volt meter on the battery (with the car off) to find the battery charge
at ~12.4 volts. Later that night we drove the car out to a friends
house and back and before I went to bed I checked the battery again
~12.8 volts (at roughly 12:00am). When I first got up in the morning I
checked the battery again ~11.4 volts (@ around 7:00am). About an hour
and a half later I put the meter on again to find the charge at ~10.5
volts. Knowing it probably wouldn't start I tried to start the car and
sure enough it would not turn over.

BTW, I am sure the alternator is good and charging the battery, as I
put the volt meter on the battery with the car started to find ~14.4
volts.

So obviously it appears I have a significant parasitic draw on the
battery occurring on the car. Especially considering it drew down the
battery almost a full volt in the course of an hour and a half. The
troubling thing here is that it appears to be sporadic. Thus when I
take it into the dealership they can't find a problem with it.

One other thing to note, I noticed the day before we started to have
problems with this car that when driving down the road sometimes you
would hear something like the air conditioner compressor (or something)
even though the heater and the radio or completely turned off. It
sounds just like when you first turn on the A/C, almost like a
mechanical whir. This noise is sporadic and occurs both when the car
is moving and stopped. Maybe this is just a coincidence, but I thought
I would bring this up.

So my question is what should I do about this issue? I am not very
mechanically inclined and I need a reliable car. I thought for sure
the guys at the Honda dealership garage would figure this out, and I am
afraid if I keep taking it in they are going to keep giving me the same
line (that they can't find anything wrong with the car).

Any help/insight would be appreciated.

Will

could be complicted or could be simple

simple like the trunk light or glove box light is on?
underhood light?
any alarm system?
extra audio stuff 2 way radio, cell phone etc not shut off?


if you have a digital voltmeter with a sensitve mV scale you can approx
measure the current without disconnecting anything...

check the meter offset by just shorting the two probes together (not
connected to the car)... the meter should read 0 mV...if it doesn't
then just use whatever it does read i.e 1 mv as the 0 value.


now connect the - lead of the mV meter to the negative post of the
battery and the + lead of the meter to the chassis of the car.

you are now measuriung the mV voltage drop across the battery ground
cable. put the head lights on (car off) and see what the reading
is... should be maybe 50 mV.

Then turn everything off,,, if you still get a reading say 5mV then
whatever is still drawing current is drawing about 1/10 of what the
headligts draw .

with the car off, and the meter connected as described above it should
read 0mV (or whatever your meter offset reading was)

this only works with sensitve voltmeters that have mV (millivolt)
scale... millvolt = 1/1000 of a volt so you are measuring the very
small voltage drop across the battery cable as a way to measure the
current draw...

Mark

Thanks for your quick response. Yeah I have a digital multimeter
actually (didn't know what it was called before). I will give that a
try if the mechanic can't fix it. I just took the car into the
dealership and explained everything to them. They called their
mechanic out to talk with me thru everything I found (as I described
above) and he said it might be a multi-plexor (sp?). I don't really
know what that is/means, but apparently it could be causing for extra
draw after the engine is shut off. Evidently they are supposed to shut
down the system after 10 min. or so. but sometimes have been known to
"stick" and thus draw too much from the battery. I will keep everyone
updated and try your suggestions if this isn't it.

Thanks,

Will

Sounds like an interesting problem.

How many miles on this car? At what mileage did you replace the
alternator?