Hi All
Just gone to get my 2002 MX5 1.8 out of my garage.
Battery too flat to start it.
Hasn't been used for 2 weeks and only had one short run in the 2 weeks
before that.
Any advice on whether this is normal?
How long should a battery last?
Is there something I can do apart from disconnect the battery to save
battery drain when the car is not in use?
Any other advice?
I will have to look up whether the warranty covers batteries.
Thanks in advance.
Hugh
PLEASE reply to group.
Jerry - 12 Dec 2004 14:21 GMT
> Hi All
>
[quoted text clipped - 4 lines]
>
> Any advice on whether this is normal?
As far as I can tell with my son's '97 Miata, its normal. I'm keeping
it for him while he's stationed in Hawaii. The intent was to drive it
once a week to keep everything perking. But I had a period where I
was out of town for three weeks. The battery was flat after that
period, and since then, it tends to go flat after just one week.
This sequence of events also happened last year. The Mazda dealer
said the battery was faulty and replaced it. It looks like it's
happening again.
Jerry
Randy Maheux - 12 Dec 2004 14:41 GMT
Generally, batteries should last more than 2 years. 4-5 years is closer to
the norm, unless you live in a hot climate, where I would expect at least 3
years. I have had Miata batteries last 4+ years here in SoCal and I have 2
years on my current one. I too was recently out of town. After 17 days
away, the 2 year old battery started the car as if I had never been gone.
If you are replacing batteries after 2 years, there has got to be either
something wrong in the charging system of your car or an unusual current
drain - it's not the battery.
Randy
> Hi All
>
[quoted text clipped - 19 lines]
>
> PLEASE reply to group.
Lanny Chambers - 12 Dec 2004 15:35 GMT
> Just gone to get my 2002 MX5 1.8 out of my garage.
> Battery too flat to start it.
> Hasn't been used for 2 weeks and only had one short run in the 2 weeks
> before that.
>
> Any advice on whether this is normal?
Not normal, but typical of cars with aftermarket alarms. Something was
draining the battery: an alarm system, or perhaps a door was left ajar
and the interior light was on. Either eliminate the drain, or disconnect
the battery while in storage.

Signature
Lanny Chambers, St. Louis, USA
'94C
the alignment page:
http://www.hummingbirds.net/alignment.html
Leon van Dommelen - 12 Dec 2004 23:53 GMT
>Hi All
>
[quoted text clipped - 19 lines]
>
>PLEASE reply to group.
Assuming the 2002 still has the Panasonic glass mat battery,
they tend to last forever without any maintenance unless maltreated.
There is a post here about one 14 years old. However, they should
not be charged above 1 or 2 amps, and require some special care
charging if really, really flat (see miata.net, garage section).
I would take Lanny's advice on checking what dark current there
may be.
Leon

Signature
Leon van Dommelen :) Bozo, the White 96 Sebring Miata .)
rammm@dommelen.net http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)
chuckk - 13 Dec 2004 22:31 GMT
I ran into an interesting problem with a four year old Westco battery. The
99 would crank, but not start well. Turned out that the battery would
accept a charge, but would not put out enough voltage under starting current
to keep the ECU and the ignition happy. Result? Odd firing timing, misfire,
backfires, etc. A bad camshaft sensor can cause similar problems. Even
worse, replacement of the cam shaft sensor may seem to cure the problem,
until the new sensor is heat cycled a number of times. For whatever reason,
the camshaft sensor seems to change sensitivity (or the ECU detection
circuitry) under different conditions, such as battery voltage.
I don't know if the later ECUs had a fix for this built in. It would be
easily possible to do.
>>Hi All
>>
[quoted text clipped - 30 lines]
>
> Leon
Leon van Dommelen - 14 Dec 2004 01:07 GMT
>I ran into an interesting problem with a four year old Westco battery. The
>99 would crank, but not start well. Turned out that the battery would
[quoted text clipped - 8 lines]
>I don't know if the later ECUs had a fix for this built in. It would be
>easily possible to do.
Operating under lower voltage, you mean? How?
Leon
>>>Hi All
>>>
[quoted text clipped - 35 lines]
>Checked by AVG anti-virus system (http://www.grisoft.com).
>Version: 6.0.806 / Virus Database: 548 - Release Date: 12/5/2004

Signature
Leon van Dommelen :) Bozo, the White 96 Sebring Miata .)
rammm@dommelen.net http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)
chuckk - 16 Dec 2004 22:53 GMT
HOW? A change in the ECU internal voltage regulator and/or circuitry is the
usual method.
It seems that all IC regulator chips are not equal. Naturally, if someone
happed to have an extra ECU or so from later models, I'd like to look at
them! <G>
>>I ran into an interesting problem with a four year old Westco battery. The
>>99 would crank, but not start well. Turned out that the battery would
[quoted text clipped - 55 lines]
>>Checked by AVG anti-virus system (http://www.grisoft.com).
>>Version: 6.0.806 / Virus Database: 548 - Release Date: 12/5/2004
Leon van Dommelen - 17 Dec 2004 01:21 GMT
>HOW? A change in the ECU internal voltage regulator and/or circuitry is the
>usual method.
>It seems that all IC regulator chips are not equal. Naturally, if someone
>happed to have an extra ECU or so from later models, I'd like to look at
>them! <G>
I should have one since I replaced mine with a Link. You are welcome
to it if you need it. I will not replace it, even if I still could
restore the connectors.
Leon
>>>I ran into an interesting problem with a four year old Westco battery. The
>>>99 would crank, but not start well. Turned out that the battery would
[quoted text clipped - 60 lines]
>Checked by AVG anti-virus system (http://www.grisoft.com).
>Version: 6.0.806 / Virus Database: 548 - Release Date: 12/5/2004

Signature
Leon van Dommelen :) Bozo, the White 96 Sebring Miata .)
rammm@dommelen.net http://www.dommelen.net/miata
EXIT THE INTERSTATES (Jamie Jensen)