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.
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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.

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<snip>
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
  Click to see the full signature.
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No aftermarket accessories, no accidents, everything runs as it is supposed to other than the battery not surviving the few weeks between drives.

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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/
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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.

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

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trade it in for a honda :)

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