Bad battery life in 97 Accord

I purchased my 97 Accord EXR (2.2L VTEC) about 5 years ago with 80,000
KM on it. It now has 185,000 KM on it and the car has been great except
for the fact that I have had to replace 3 batteries and 2 altenators in
that time. This doesn't seem normal to me. Does anyone know what could
be prematurely killing my battery? I understand that a bad battery
could very well reduce the life of the altenator so I believe I should
probably concentrate on the battery. TIA.

 

Have you done many jump starts on the batteries it's had?

Running a battery down will exponetially reduce its life.

Also, if you have done many jump starts on the batteries,
then subsequently relied on the car's alternator to charge
them, this will reduce the alternator's life. Alternators
are not designed to do more than routinely trickle charge
the battery.

Also, look at the battery and alternator discussion at
http://tegger.com/hondafaq/faq.html

http://home.earthlink.net/~honda.lioness/id13.html may have
some ideas for you, too.

 

| Alternators
| are not designed to do more than routinely trickle charge
| the battery.
Honda's spec for my F20A says alternator can produce 80 amp :
trickle charge my foot. If your crap is true, then using car with high
beam on, i.e. drawing more amps fr alternator should kill alternator (
mine has powered high beam for 10 hr since 1990, & is as good as
new ).

www.batteryfaq.org

 

I purchased my 97 Accord EXR (2.2L VTEC) about 5 years ago with 80,000
KM on it. It now has 185,000 KM on it and the car has been great except
for the fact that I have had to replace 3 batteries and 2 altenators in
that time. This doesn't seem normal to me. Does anyone know what could
be prematurely killing my battery? I understand that a bad battery
could very well reduce the life of the altenator so I believe I should
probably concentrate on the battery. TIA.

I had this same problem with a Chevy Monza. It took over a year but I finally
traced the problem to a problem with a major electrical wire that was
shorting out since it was not spliced together properly. After I spliced
the wire properly, the problem was solved. I seem to recall that it was
the wire
in that connected the starter to the alternator. The wire was able to
carry electricity but not as much as was required for the alternator to
work properly. As a result, the alternator would stop working and the
battery would eventually go dead. Your problem may be caused by something
else but you should check the wiring.
Jason

 

80 amps at 14 volts is 1120 watts; standard high beams are 55W apiece - only
10% of the peak alternator capacity for the pair. http://tinyurl.com/3k724

The alternator damage comes from the way alternators are rated. Alternators
won't put out more than the rated current even into a short circuit as long
as the excitation voltage is normal. That rating is designed to match the
diode capacity, since even a few seconds of overcurrent will short the
diodes. Your 80 amp alternator will safely put out 80 amps for a minute,
maybe two... beyond that the wire resistance will overheat the stator and
cook the insulation. I canna' change the laws of physics: it would require a
minimum of 10 AWG windings to carry 80A continuously and there just isn't
room for that and there sure isn't room for the ventilation it would demand.
As the alternator gets hotter the diodes will also be at risk. By that point
your battery will be losing water from the extreme charge rate - if it is a
"maintenance free" battery it will vent and be permanently damaged.

Modern high current alternators provide much better performance than the old
35 amp workhorses - an important consideration with all the electronics and
accessories. The trick is that you must not demand that sort of current for
more than a minute or two or you will be replacing a lot of alternators and
batteries. The old alternators had better cooling (larger units and more
space around them) and would put out rated capacity all day. The newer ones
are very nice, but don't mistreat them by using them as battery chargers.
They won't put up with it, and neither will your battery.

Mike

 

If you find what is draining the battery you will find the answer. FWIW, a
fairly common gotcha is the light in the glove box. If the light doesn't
reliably go out when the glove box door is closed it secretely sabotages
you.

Mike

 

Nice explanation! Well-written, too.

 

I had a similar problem with a '96 Volvo which I finally traced to the
glove box light staying on. This was draining the battery down every
time the car was off. Lead acid batteries do not take well to being
deeply discharged repeatedly.

I didn't finally figure out what was going on until leaving the car at
the airport for two weeks resulted in a dead flat battery which didn't
want to come back to life. That caused me to hook up a current meter to
the battery and start pulling fuses until I found the circuit with the
current draw. Beefed up the glove box switch striker plate, installed a
new battery and has been working properly for years since.

One little light doesn't use much power, but when left on for days at a
time it does the trick.

You might have some similar vampire soaking up power when the vehicle is
off.

John