Hello there,
Has any of you experienced problems with a Cobra alarm 77 (or 79) series?
The problem is that the battery keeps going flat all the times (completely
dead).
I wasted so much money to tackle this problem untill I found out that the
Cobra alarm might be the cause.
Unfortunately I didn't find a solution in the newsgroups and Google.
Any ideas?
Please bear in mind that I just subscribed to this news group so I dont know
whether this matter is covered before or not.
Although I have this alarm for the last 3-4 yrs I never had problems but
this was because I was using the car every single day. Now, if I don't use
it for 2 days or so...the battery is dead!
Checked every thing (i.e alternator,battery). Everything is ok (changed 3
batteries!)
Any suggestions before I spend more money to remove this damn thing are VERY
welcome!

Thank you

Chris

On Tue, 30 Sep 2003 10:37:25 +0000 (UTC), "Advance"
wrote:


Has any of you experienced problems with a Cobra alarm 77 (or 79) series?
The problem is that the battery keeps going flat all the times (completely
dead).

I've heard people say this with various alarm systems, I'd guess,
something like several hundred times. Upon testing though, the alarm
was the actual cause in probably something like 3 or 4 cases.
Invariably it's the battery. Where it's not that, it's the alternator.
Where it's not either of them, it's something else completely
unconnected with the alarm.

Any *competent* auto electrician should be able to tell you the
problem in less than an hour:-

1) Test battery. The sad fact is that very few people know how to do
this properly. The battery needs to be fully charged, specific gravity
tested on each cell, load tested, left to recover and then load tested
a second time. Most "Battery Test Stations" don't even have decent
battery drop testers these days.

2) Disconnect battery - connect ammeter inline. This will immediately
tell you whether it's a drain problem, or just that the battery isn't
getting charged properly in the first place/has a fault.

3) If it is a drain problem, connect an ammeter directly in the red
main live feed to the alarm. This will then tell you if the alarm's
drawing more than it should. If not, then it's either an indirectly
related probem (ie. a door switch line causing a boot light to stay
on, etc) or else nothing to do with the alarm.

If you do all the above and still can't localise the problem, let me
know your findings and I'll see if I can give you any more pointers.
Gut feeling though is that it's probably a battery problem. Around
this time of year, the sudden drop in temperatures invariably causes a
battery that's in any way suspect to die suddenly. When I was
installing full time, around this time of year I'd probably end up
going out to a call out once a week or so for an "alarm problem" that
turned out to be just a dead battery.

Jon
--
In-Car Express http://www.incarexpress.co.uk
Car Audio | Security | Multimedia | Navigation
Tel. 01223 301212 Fax. 0870 7484 123

Well Jon,


I think you are the right person with the right knowledge but apparently at
the wrong location considering where I am now!

Anyway I will be contacting you directly as I am interested to buy the SONY
CDX-MP40 head unit but I am wondering whether it's compatible with my old CD
changer that I have. It's a SONY 10cd changer but I can't remember the model
now (not Xplod series).

Anyway for the time being, I need to sort out the problem with the alarm
and/or the battery.

This is what I have done:



1- I went to collect my old (1-2 months old) battery from my local
mechanic. Since he installed the battery during the last service I was
covered from warranty so he gave me a new one. He told me that the problem
was DEFINITELY the battery and I shouldn't worry about it anymore.

As I find it ridiculous to change 3-4 batteries in a 3 year period I am very
suspicious that the problem lies on the car and not the batteries.

The new battery details a BOSCH 12V 50Ah

2- As I am not a car electrician I'm afraid not to loose this battery as
well so I installed it ONLY for the testing and then I removed it.

3- I switched my home multi-meter to 20V DC to register the battery's
voltage. The finding was 12.57 (the battery is not yet connected to the
car).

4- Then I connected the multi-meter inline with the positive (red) pole
and the car's positive cable. The multi-meter was switched at the position
10A. The finding was 0.45 to 0.50. This finding was the same with the alarm
in both modes (armed & disarmed)

5- Bear in mind that the only 2 things that *I* am aware that are
consuming power are the car's analogue clock and the Alarm. The car stereo
is in place BUT without it's front panel.

6- Although I am not an electrician I think that these findings in plain
English mean that I consume the one 10th of what the battery can give
(1/10). If this is right....isn't that quite high?


Unfortunately I didn't measure the alarm's main feed as it's quite hard for
me to reach it and I need space and time to do it. Probably tomorrow
(Sunday). I need to find the COBRA manual first and then practice my Italian
as this is the only language used.. ($"!£^%£$^£$^&$)



Please let me know what you think and send me your direct email address to
discuss the SONY matter further.

Thanks a lot
Chris




"InCar Express" wrote in message
news
On Tue, 30 Sep 2003 10:37:25 +0000 (UTC), "Advance"
wrote:


Has any of you experienced problems with a Cobra alarm 77 (or 79) series?
The problem is that the battery keeps going flat all the times
(completely
dead).

I've heard people say this with various alarm systems, I'd guess,
something like several hundred times. Upon testing though, the alarm
was the actual cause in probably something like 3 or 4 cases.
Invariably it's the battery. Where it's not that, it's the alternator.
Where it's not either of them, it's something else completely
unconnected with the alarm.

Any *competent* auto electrician should be able to tell you the
problem in less than an hour:-

1) Test battery. The sad fact is that very few people know how to do
this properly. The battery needs to be fully charged, specific gravity
tested on each cell, load tested, left to recover and then load tested
a second time. Most "Battery Test Stations" don't even have decent
battery drop testers these days.

2) Disconnect battery - connect ammeter inline. This will immediately
tell you whether it's a drain problem, or just that the battery isn't
getting charged properly in the first place/has a fault.

3) If it is a drain problem, connect an ammeter directly in the red
main live feed to the alarm. This will then tell you if the alarm's
drawing more than it should. If not, then it's either an indirectly
related probem (ie. a door switch line causing a boot light to stay
on, etc) or else nothing to do with the alarm.

If you do all the above and still can't localise the problem, let me
know your findings and I'll see if I can give you any more pointers.
Gut feeling though is that it's probably a battery problem. Around
this time of year, the sudden drop in temperatures invariably causes a
battery that's in any way suspect to die suddenly. When I was
installing full time, around this time of year I'd probably end up
going out to a call out once a week or so for an "alarm problem" that
turned out to be just a dead battery.

Jon
--
In-Car Express http://www.incarexpress.co.uk
Car Audio | Security | Multimedia | Navigation
Tel. 01223 301212 Fax. 0870 7484 123

On Sat, 4 Oct 2003 15:55:19 +0000 (UTC), "Advance"
wrote:

4- Then I connected the multi-meter inline with the positive (red) pole
and the car's positive cable. The multi-meter was switched at the position
10A. The finding was 0.45 to 0.50. This finding was the same with the alarm
in both modes (armed & disarmed)

Sorry it's been a few days. Been v.busy, and I've not had the chance
to look at usenet up to now. 0.5A is a significant drain - very
significant! It'll probably flatten the battery in around about 2
days. After that point, it'll start to 'deep cycle' the battery,
sending it into a state where it'll never fully recover it's original
charge (ie. it's scrap!).

If the drain's similar in either alarm state, I doubt that it's going
to be the alarm that's at fault. The simplest way to rule out an alarm
*unit* fault is to make sure the alarm's disarmed, to unscrew the
cover on top of the alarm, and to unplug the main wiring loom into it
(you need to make sure the alarm's fully disarmed at the time, or
you're likely to activate the battery backup). If you then take
another current measurement, if it's dropped away to nothing, the
alarm brain's dead. If not, then the problem's elsewhere.

5- Bear in mind that the only 2 things that *I* am aware that are
consuming power are the car's analogue clock and the Alarm. The car stereo
is in place BUT without it's front panel.

1/2 an amp points to either an amp staying switched on, or an interior
light somewhere. It's possible for an alarm cable grounding out to
cause a boot light to stay on. Have you checked for this?

Other than that, it could also be virtually anything electronic within
the vehicle (ie. engine ECU, gearbox ECU, ABS ECU, etc, etc). Once
you've ruled out the alarm, the next step is to remove fuses on
accessory circuits until you find the one that causes the drain to
disappear. Check the vehicle manual before doing so though, as it can
have an adverse effect on some vehicles.

Jon
--
In-Car Express http://www.incarexpress.co.uk
Car Audio | Security | Multimedia | Navigation
Tel. 01223 301212 Fax. 0870 7484 123

In addition to Jon's answer, I had problems with my first Vectra where
the battery wouldn't hold a charge. It was eventually found to be
that the rear window heater was staying on with the ignition off, but
this was only after I'd had it at 2 respected auto electricians who
could find nothing wrong and then taken it to my Vauxhall dealer.

Might be worth bearing in mind.