Will an alarm system 'drain' a battery in a sitting car, if alarm is not "set"?

[Maynard Krebs]

In my Cadillac 'wannabe', a nice '89 Caprice, I've found, to my embarrassment, chagrin, and annoyance, that apparently I cannot leave the battery connected over the long Winter 'cause "something" drains it.   I suspect that it's the alarm system, even though I do not "set" it, nor "turn it on".   I cannot guess any other reason why the new battery, freshly charged in early November, will be 'dead' by March.  Aggravating!

Is this "normal"?   I know that batteries self-discharge a little over time.... but to go completely 'dead'?

The reason that I left it connected is because it is so difficult for my hands to access the side terminals, because of other stuff all around it.   I guess that I'll have to change my habits.

What about you guys?   I know that it's "safer" to disconnect the battery over the Winter.... because any car could develop an electrical short, which could cause a fire.
So, I admit that it makes good sense.   I guess that I was trying to take the lazy man's approach---and it does not work... with GMs, anyway.

[76eldo]

It's normal and to be expected.

Either hook up a battery tender or disconnect it.  A charged battery will hold a charge all winter if disconnected.

Brian

[Walter Youshock]

If the "Security System" light is off with the doors closed then I say it's normal.  Reason I say this is my '91 Brougham developed a problem with the light staying on.  It turned out to be a defective trunk lock unit that grounded the switch and made the car "think" it was broken into.

[The Tassie Devil(le)]

The big problem with these newer cars is in the electronics department.

The clocks continue to run, the computers still require power, and therefore are constantly draining the battery.

Plus, a lot of modern batteries are being made using recycled lead (Made in China) and aren't lasting as long as the ones made with pure lead.

Batteries that used to last 8 years, are now only lasting 2 or 3 years.

Bruce.

[tripwire]

Like Bruce said.  It's what's known as a parasitic draw.  Cars with computers use just a bit of electricity, in addition, the clock and radio use a bit to keep your stations set and time correct.  If you find the battery going dead in just a couple days you've got something pulling more power, like a trunk or glove box light staying on.

WParo in VT

[savemy67]

Hello Gerald,

There are adapters available that convert side-mount terminals to top-mount.  This would make disconnecting the battery less onerous, if you have the space with the hood closed.  A battery disconnect switch can be used to disconnect the battery instead of removing a cable from a terminal.

If you suspect your alarm is the source of the parasitic draw, measure your battery voltage at the battery on the first of a month when you do not plan on driving the car.  Measure the battery voltage at the end of the month.  Note the voltage difference.  On the first day of the ensuing month (again, without starting the car), disconnect the alarm system making sure power and ground to the alarm are physically disconnected.  At the end of the month, measure the battery voltage (if the electrolyte in the battery's cells is chemically correct, a lead acid battery will usually discharge in a linear manner).  If the difference in voltage of the second month is less than the difference of the first month, it is possible that the alarm is causing the discharge over the Winter months.  However, an alarm system that is not armed and operating may not draw enough current by itself to cause the battery to discharge.  You may have other parasitic draws, so you may want to check all the circuits in the car.

Respectfully submitted,
Christopher Winter

[The Tassie Devil(le)]

Forgot to mention that when I go away, I have to disconnect the batteries in my cars, especially the late model one as the last time, it was flat after six weeks of non-use.

The '55 Buick has no problem, and the Eldo has a trickle charger attached, unless I am driving it on the holiday.

Bruce.

[Scot Minesinger]

You can get a real good "T" handle 900 amp disconnect for the negative on the battery that an eleven year old can easily operate, rather than the green twist type.  I got this from Summit Racing, "Flaming River", at a cost of about $100.  Hook negative battery cable to switch you mount, then buy a #2 connector 2' long from other side of switch to ground that was where the original was connected - super easy.

BTW, all winter you need to disconnect the battery or it will drain.  This was true of my 1965 Thunderbird even in the 1970's, probably cause of clock.   I drive my Caddies every week if possible, but when I see a two or three week no drive thing coming up, I turn the disconnect switch.  Plus super handy for service.

[bcroe]

There are a couple of problems.  Almost all cars have some drain all the time
(clock, much more), AND batteries will self discharge with no load.  If sufficiently
discharged, a hard (ILL - 20 F) freeze will freeze and destroy it.  A battery
disconnect switch won't solve the latter problem, and has other issues. 

I got fed up with buying new batteries every spring, for hardly used stuff,
like my tractor, generator, or parked car.  I bought half a dozen Horrible
Fright battery maintainers, for well under $10 each.  I put extra long cords
on some so they would reach the required outlet without risky extension
cords; no more ruined batteries. 

At this point many of my cars have a small custom connector for the battery
instead of the crude, somewhat unreliable battery clips.  EC3s (model) are
cheap, compact, polarized, and robust, I put an extra blanked out plug over
them to keep them clean when driving.  Handy for other stuff needing battery
(timing light, etc). 

Understand a MAINTAINER sets a voltage to prevent over charging; a
trickle charger could over charge and drive battery water out in time.  No
need here for the maintainers costing dozens of times as much. 

DO NOT let your maintainer get unplugged, or it will probably run your battery
down even faster. 

I did try a solar "maintainer" that plugged into the lighter socket, but with
the average winter sun, it just couldn't keep up with the clock drain.  I
tried removing the clock fuse, but it turned out the lighter used it too. 
Bruce Roe

[Scot Minesinger]

Bruce, why not just disconnect the battery?  Much easier.  Used to do that when I went off to college from late August to mid May, started right up after connecting battery.  Had same battery for years.

[The Tassie Devil(le)]

Plus, don't store batteries on a concrete floor.   If you have to, put a piece of tinber, or a sheet of rubber between the battery and the floor.

Bruce.

[bcroe]

  Bruce, why not just disconnect the battery? 
Much easier.  Used to do that when I went off to college from late August to
mid May, started right up after connecting battery.  Had same battery for years. 

Scott, do what works for you.  I have one solution that solves every problem
here.  I think plugging a connector not much bigger than my thumb nail, is a
lot easier than messing with a big dirty battery terminal, that is not designed
for frequent work.  If I decide to do something with a car (other than drive
it), the lights and everything else work, even the starter, without removing
the maintainer.  My backup generator could sit for years, and will surely self
discharge to distruction without a maintainer.  And the self discharge rate of
a battery can vary; I don't have to worry how bad it is or how cold it is. 

There is a thought to build a central maintainer that is more energy efficient. 
When your battery tops, the HF maintainer will continue to use some 3W (I
have a lot of them).  It will probably run at 24VDC (to avoid distribution
voltage drop), with one of those $1 switchers dropping it to the exact 12V
level needed.  The battery lead would have a series diode (to avoid any
battery discharge).  And a small series 24V light bulb, which would simply
light to indicate a reverse connection.  At higher charge rate the bulb would
put a limit on current; near final low level current the resistance of the bulb
drops by a factor of about 20, allowing final charge to the correct voltage. 
However its not taking shape very quickly here; been working the ground
around my solar panel system.  Bruce

[bcroe]

Plus, don't store batteries on a concrete floor.   If you have to, put a piece of
timber, or a sheet of rubber between the battery and the floor.  Bruce.

I am waiting for someone to convince me, that this isn't an old wives tale. 
the other Bruce

[The Tassie Devil(le)]

I know that whenever I leave a battery on the floor, it is worthless after a while.

Down here, we use a steel mesh in our slabs for reinforcement.   Could be some sort of "magnet"?

From what I saw in US, they use a lot of fibreglass mesh and other stuff.

Bruce.

[55 cadi]

From what I was told is to never put a battery on the ground, even concrete, it makes a "ground" and shorts/grounds the battery.

I also use a wood piece between battery and floor.

I was told this over 20 years ago when I did car electronics, by multiple sources, including Alpine electronics, i knew someone that worked there.

[Glen]

I am waiting for someone to convince me, that this isn't an old wives tale. 
the other Bruce

I’m with you Bruce.  Nobody has come up with a logical explanation as to how that works.  Some have said the concrete shorts out the battery, but if that was true why wouldn’t the steel battery tray short out the battery?   

[The Tassie Devil(le)]

Just talked to an electronics whiz, and for these new batteries, with the plastic cases, sitting on concrete is not a problem.

What came out of the past was that when batteries had the rubber case, and sometimes they tendered to leak, then the mess that was laying on the concrete would gradually allow the current to follow the leak "stream" and it was this that killed them.

But, that being said, I don't like charging batteries on a concrete surface as when they overflow during the charging process, which they sometimes do, the acid makes a mess on the concrete.

Bruce.

PS.   The trouble with our older cars, we want to stay with the old-style batteries, and some could still have the rubber case.