Re: Door lock module contributing to battery drain

["jtrealty@xxxx " <jtrealty@xxxx>]

To properly check the source of the current drain put an ammeter on 
the battery positive connection and observe the total current draw. 
Now one at a time pull fuses. You will find that there is draw from 
more than 1 fuse but the major amount will be drawn by #12 the door 
and interior light circuit. Typically 10 m.a. is considered normal
for 
a car sitting, it will take a month to discharge a good fully charged 
battery. Normal on a Delorean is usually quite a bit more. The cause 
is the many diodes in circuit #12. It is true that a diode is like a 
"check valve" but it is a leaky one. Each one adds up to a large 
cumulative effect.They can also fail by getting more leaky not just 
open or shorted. If you are confident that you have a good 
battery(load test it) and that all of your electrical connections are 
good then the problem most likely is in circuit #12. If the battery
is 
more than 4-5 years old and it has spent it's life 1/2 in storage and 
1/2 being used it is probably not able to provide full capacity and a 
load test will show it. Also if there is a problem in the charging 
circuit and the battery is always undercharged it will shorten the 
life of the battery. Another source of this problem are the door 
switches. There is a rubber tip on them and with age or maybe it's no 
longer there the switch can make contact even with the doors closed. 
With the interior lights off you wouldn't see the door lights still 
on. The ultimate solution is to install a master switch with a bypass 
fused wire to the clock. Then at shows the doors can be left open and 
you don't have to worry about the battery. It is also a good theft 
deterrent if you get the one with a removable key.Most people 
unfamiliar with a Delorean would never find the battery let alone the 
master switch.If you have a measurable current in the door lock 
circuit there is a problem, it should not have a measurable draw.
David Teitelbaum
vin 10757 and yes I have a master switch with clock bypass.




--- In dmcnews@xxxxxxxxxxx, "Grimsrud, Knut S" <knut.s.grimsrud@xxxx> 
wrote:
> Because I have a daily driver DeLorean in addition to my new one 
that I'm
> restoring, my good DMC doesn't get out much during these rainy 
winter months
> (I'm in Oregon, so it gets pretty sloppy around here this time of 
year).
> I've been a little curious about the gradual battery discharge that 
our cars
> seem to be so susceptible to, so I did a little investgating last 
weekend.
> 
> It is well known that the console clock and radio consume a trickle 
of
> current. However, when pulling the radio fuse there is still a 
slight power
> drain (at least on my cars). In fact, after pulling all the fuses
my 
cars
> still have a power drain from the batter of around 11mA. This isn't 
very
> much, but is sufficient to slowly degrade a battery over time.
> 
> In trying to track down this power trickle, what I found was that 
the door
> lock module on my car draws the additional 11mA of current. I 
haven't
> disassembled or reverse-engineered the module yet to understand why 
it draws
> a trickle current, but it appears to do so. I'm not sure if the 
LockZilla
> similarly draws a trickle current as I only have stock door lock 
modules in
> my cars.
> 
> If you suffer from inexplicable battery drain for a car that's 
stored for
> periods, the door lock module appears to be one of the contributors 
to the
> problem. I still need to recheck my measurements this weekend, but 
it
> appears that removing the clock/radio fuse and unplugging the door 
lock
> module may be sufficient to avoid battery drain without the need for
> installation of battery cutoff switches, trickle chargers, etc.
> 
> Knut