Battery Problem

A good friend of mine has a year 2000 VOLVO S70 AWD with a mere 35,000 miles
on it. I am posting this here because the VOLVO board is not very active and
the problem is probably something you folks know about.

My friends live here (Pittsburgh) but spent 6 months in Florida, hence the
low miles. While they are in Fla each year the Volvo sits in their garage
here. My job is to start it and drive it occasionally. In 2003, the battery
died in spite of me driving it. I put in a DIEHARD for them. Again two weeks
ago, I went to start the car to prepare for their return and, in spite of
starting and driving all winter thru some bitter cold spells, the battery
was dead and would not recharge after a jump and drive.

Is there something in that car that drains the battery when it sits for,
say, 2 weeks without being driven? And is there any reason NOT to disconnect
the positive terminal next winter and perhaps move the battery into the
warmer house? I also hear there is a "switch" that accomplishes the same
thing as disconnecting the terminal. What about a trickle charger? Any
danger of leaving one of those on with no one home and maybe for 2 weeks
without inspection? Any ideas/thoughts on this relatively minor but annoying
problem would be appreciated.

 

I would check for excessive amperage drains on the system and repair....if
drains are not excessive then I would have the battery checked and charging
system.

Aside from that there should be no problem driving the car every few weeks.
The battery should be fine. I would buy an auto shut off trickle charger
and just keep it on their all the time and not have to worry about taking
the battery out. I wouldn't disconnect the battery completely since the
clock and radio stations would have to be reset and this just isn't
necessary.

 

I have to ask: Are there any aftermarket add-ons installed?
*Stereo
*Alarm
*Remote start
*Fog/driving lights

Has the vehicle been involved in a collision?

Do all the lights work properly? (Don't overlook trunk and glove box
lights!)

Battery drainage problems are usually due to poorly-installed accessories.
A 2000 model-year car is a bit new for corrosion-related drainage.

 

No aftermarket accessories, no accidents, everything runs as it is supposed
to other than the battery not surviving the few weeks between drives.

 

D.D. Palmer wrote:
| No aftermarket accessories, no accidents, everything runs as it is
| supposed to other than the battery not surviving the few weeks
| between drives.

OK, I don't know what the capacity for this battery is. Let's assume 50Ah.
In fully charged and perfect condition, that would give you 50 hours of 1A.
If you had a load of 20mA (essentially a single LED turned on), that would
give you 1,000 hours (41.6 days) before the battery is completely
discharged. With 40mA, that would reduce to 20.8 days, not taking into
account any sort of self-discharge rate. Also, the car will most likely be
unable to start much earlier than "fully discharged"

The only way you have to tell is to hook up an ammeter between the battery
and the wire going away from it. Once you know the current (and the battery
capacity, and ideally the state of the battery), you'll be able to estimate
the time it can stand around wthout being started.

If you do let it go into deep-discharge, you will irreversably damage the
battery. The electrodes change chemically and will not be able to hold much
of a charge anymore.

The first task would be to find out how much current is being drawn in the
"off" state; is there an alarm? Any additional current sinks?

Also, consider that your drives may not be recharging the battery fully.

|| ||| |||
|||| A good friend of mine has a year 2000 VOLVO S70 AWD with a mere
|||| 35,000 miles on it.
|||
|||
||| <snip>
|||
|||
||||
|||| Is there something in that car that drains the battery when it sits
|||| for, say, 2 weeks without being driven?
|||
|||
||| I have to ask: Are there any aftermarket add-ons installed?
||| *Stereo
||| *Alarm
||| *Remote start
||| *Fog/driving lights
|||
||| Has the vehicle been involved in a collision?
|||
||| Do all the lights work properly? (Don't overlook trunk and glove box
||| lights!)
|||
||| Battery drainage problems are usually due to poorly-installed
||| accessories. A 2000 model-year car is a bit new for
||| corrosion-related drainage.
|||
||| --
||| TeGGeR®
|||
||| The Unofficial Honda/Acura FAQ
||| www.tegger.com/hondafaq/

 

I saw your post on the Volvo group - it actually gets almost as much
activity as this group does. Keep an eye on that post, too... the gurus
there (Mike F, Robert Dietz, and others) can tell you if there is something
you need to know about the S70 charging system.

Mike

Mike

 

Thanks for that tidbit about the Volvo group! I'll keep watching!

 

trade it in for a honda

 

Check the clock. My uk car is a 89 340, the clock will drain the
battery in about 5-6 weeks.

Nice maths. Slightly off though. Battery capacity isn't a linear curve
of current against time. Batteries are rated on a 20 hour discharge. a
50Ah battery will do 2.5A for 20 hours. it might only do 5Ah for 8
hours, or 1A for 75 hours. its a logarythmic curve.

A distinct possibility, and also make sure its topped with water where
needed. i left my 340 at Manchester Airport car pack for 3 months back
in 02, fully connected, with the clock going (the 340 has a nice big
manual clock on the dash by the speedo) Father was concerned it'd be
flat when i came back, it ran real good though. it was a 40-odd mile
drive to the airport though, so a good charging run.