Re: Bad battery life in 97 Accord
 

"Homer Simpson" <moose151@gmail.com> wrote in message
news:200605180718227284-moose151@gmailcom...
>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.
>
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

Re: Bad battery life in 97 Accord
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote
E
>>| Alternators
>> | are not designed to do more than routinely trickle
>> charge
>> | the battery.
snip
> 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.

Nice explanation! Well-written, too.

Re: Bad battery life in 97 Accord
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote
E
>>| Alternators
>> | are not designed to do more than routinely trickle
>> charge
>> | the battery.
snip
> 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.

Nice explanation! Well-written, too.

Re: Bad battery life in 97 Accord
 

"Michael Pardee" <michaeltnull@cybertrails.com> wrote
E
>>| Alternators
>> | are not designed to do more than routinely trickle
>> charge
>> | the battery.
snip
> 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.

Nice explanation! Well-written, too.

Re: Bad battery life in 97 Accord
 

Homer Simpson wrote:
> 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 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

Re: Bad battery life in 97 Accord
 

Homer Simpson wrote:
> 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 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

Re: Bad battery life in 97 Accord
 

Homer Simpson wrote:
> 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 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