Battery dies in heat in '97 850 GLT wagon

No auxillary power units being turned on in the sun that could wear the battery down?

broye wrote:

No I only have the passive security system that runs, the clock and that is about it. I do not have any type of addons.

I've done a little Googling and found out that heat is very bad for a battery, even worse than cold.

"In a hot climate, the harshest environment for a battery, a Johnson Controls survey of junk batteries revealed that the average life of a good quality car battery was 37 months."

Also I read the explanation is: Temperature will kill a battery over time. If a battery gets too hot, its self-discharge rate goes up. If the battery gets to cold, the reaction that produces electricity gets slowed down and the full capacity cannot be ``harvested.''

It's been averaging between 98-105F where I live (not counting the heat index), my battery is fairly new so I haven't had any heat problems. I suspect yours may be a few years old and is dipping just below cranking amperage in the heat.

broye wrote:

FWIW, give yourself another sanity check...take a look at:

- glove box light [sometimes the switch doesn't break and/or the door doesn't close all the way]

- rear tailgate lamp [if the tailgate doesn't close just right, it will stay on...and if your ~6ft as I am, or don't drive at night usually, you may not see the illuminated lamp in your rearview

- look at the lamps above each of the rear doors, make sure they are not in manual override

- you said your battery is new...how new ? make/manuf/CCA ? If it is indeed a Volvo battery, they run 550-590 avg CCAs, others [Interstate in particular] run 650+ CCA.

- these things are notorious for ZERO warning on battery failure...one day fine, MAYBE a little slow on 1 or 2 starts, and then NOTHING

- many of us who live in New England with our extreme temperature swings replace every 2 [sometimes 3] years

just my $0.02, hope some of this is helpful

C> I live in the Northeast. We have been experiencing some hot weather the

...and, so called 'maintenance free' batteries aren't really! Pop the caps off and see if the plates are exposed. I've found half the electrolyte gone on batteries less than 2 years old. Refilling with water will rejuvenate them temporarily, until you can replace it on the weekend.

Not necessarily with the heat, but the symptoms are familiar. I believe the battery has broken connections inside. Once the connections make contact the battery tests good. The "last gasp" really sounds like that problem, especially when you add the car turning over immediately when jumped. Living in Phoenix I saw that a lot, so maybe heat does have something to do with it.

A good diagnostic for that (other than swapping batteries with another car) is to carry a small hammer in the car and when the symptom returns give each post a whack or two - not hard enough to break the case, of course, but about what you would do to crack a tough nut. That often restores contact and allows you to start the car. You can also turn on the lights and watch to see if they come on when you whack the posts.

If the battery is two or more years old, I wouldn't even bother with that - I'd put a new battery in. I'm pretty sure that will solve your problem.

Mike