The first thing to do is to measure parasitic draw correctly... more on that
in a bit. If this is the original battery, you are due for a replacement.
The test equipment used by most auto parts stores is far from professional
quality.
As for parasitic draw testing.... there are many modules on even a 98 and
some of these modules require anywhere up to 45 minutes to "go to sleep".
Something as innocent as opening a door or pulling and reinstalling a fuse
can be enough to "wake a module up"...
Many batteries can pass a high rate discharge test yet fail a reserve
capacity test miserably...
On 9/10/06 9:16 PM, in article 2y4Ng.2094$KA6.578@clgrps12, "Jim Warman"
<mechanic@telusplanet.net> wrote:
> The first thing to do is to measure parasitic draw correctly... more on that
> in a bit. If this is the original battery, you are due for a replacement.
[quoted text clipped - 8 lines]
> Many batteries can pass a high rate discharge test yet fail a reserve
> capacity test miserably...
Jim, thanks for the response. I'm not entirely sure what you're suggesting
though. Are you saying I should wait 45 minutes without doing anything and
test again? If so, could you explain further?
And as for the battery, wouldn't the symptoms be different if the battery
were bad? I never have a problem if I drive the vehicle every few days. It's
only a problem if I park it for a week without driving it. Then if it is
dead and I charge it, it works fine for another week of no driving.
Thoughts?
Steve
Jim Warman - 12 Sep 2006 06:43 GMT
Prepare the car ahead of time... open the doors and trip the latches to the
closed position (makes the car think the doors are closed.... This way,
opening a door wont wake a module up.... I like to pre-install a tool
similar to this
http://www.amazon.com/Battery-Disconnect-Switch-Will-Both-Side/dp/B00099YOV8
to the positive post before I do anything else.... make sure your ammeter is
connected across it before you open the switch.
Allow at least 45 minutes for all the modules to hibernate and then begin
testing. Once a fuse is pulled, do not re-install it until testing is
complete - re-installing it *may* wake a module up.
A poor mans reserve capacity test..... turn on the interior light and
operate the radio for about an hour and a half.... If the battery has
sufficient reserve capacity, the car should start.... If not, it could be a
very real indication that reserve capacity is down and the battery may need
replacing. As I said, if this is the original battery, I wouldn't hesitate
to replace it, anyway...