Battery Drain

Is it possible for a car alarm to all of a sudden start draining your battery. I cant think of anything else. It is the original battery from 09.
What I dont get is if I put a multimeter on the battery it will show over 13 volts but still will not start the truck.
Is is possible that the battery has just gone bad? There is not anything being left on. I have not really been driving the lately...hmm maybe thats the reason...trucks parked, alarms consuming juice.. I dont know.


thanks

 

not starting up a vehicle for awhile will drain the battery

 

Batteries are meant to be replaced annually. A bad battery will measure 12v, it's about amperage, not voltage.


Edit: you folks are right, most manufactures recommend replacing your battery every 3-4 years. But I agree, replace them when they're starting to go bad.

 

All batteries will have a little amperage drain on them from the computer etc on newer vehicles, it's called parasitic drain.

I would suspect that your battery has a bad cell, that's what usually happend when you have full voltage but no cranking amps, an easy way to tell is to put a battery load tester on it. Something that like autozone or someone can do for you for free. When you hit the tester and the needle dives away....the battery is poop.

Otherwise a bad connection (dirty terminals) or a bad wire will do that. But from my experience it's not typical of the Tacos

 

The first part is inaccurate, unless they are just cheap ass batteries. Batteries should last years depending on the brand.

 

i still have the original battery in my 06

 

OK thanks, I guess I will be pulling the battery off and getting it checked out.. It sounds like its time for a new one..This the first time I have had an issues with it..

 

You're right. I just want to nit-pick a little bit because I'm slightly butt-hurt.

If his truck wont start, and he's getting 13v at the battery, he's probably going to get a voltage drop of 13v when he tries to start it.

Also, there is no such thing as potential voltage. Voltage is potential difference. You shouldn't not not ever call it that.

 

Ya its somewhere around 13v or more, I cant exactly remember I just know it was always above 12v.

Thanks

 

Keep in mind you need to drive the truck a bit to replenish... If it's hard starting or reading low take it for a driver for 20 minutes and then try things out.

 

There's a few common problems you can have with a battery. One of them is parasitic drain, that's where your radio, ECU, alarm, etc are all pulling a little bit of current from the battery at all times and run the charge down. With a 'normal' parasitic draw this can happen if the vehicle sits for about 2 weeks or so, sometimes even less. I've had batteries that go flat in a week of no usage. It's not so much a problem with the battery as just a sustained slow drain using up all the charge. If you tend to leave the vehicle for a period of time like this a trickle charger/battery maintainer is your best friend.

If you have a battery that shows decent voltage but can't crank there's a couple possibilities. What's happening is the voltage us there but the current isn't. It's kind of like a kinked garden hose. You might be able to pull the trigger and get a spurt of water but the kink in the hose kills the flow right away.

You can have this situation when the battery terminals are dirty or corroded. They make good enough contact to deliver the full voltage but not good enough to flow the full current. Pull the terminals off and clean them, that's the easiest and cheapest first step. There's a battery terminal cleaning tool available at any auto parts store.

Corroded battery cables can do the same thing. Like cruddy build up on the inside of drain pipes it can choke off the flow.

Next is a damaged battery. The plates in a battery can get crystalline build up on them that reduces the surface area. Less surface area = less chemical reaction = less current. This happens with time in a battery, also it can be caused prematurely by the battery sitting in a discharged condition, which is another good reason for a battery tender if the vehicle sits unused.

You can also have plates crack and come apart inside the battery. I think they usually won't make voltage then but that can cause battery failure too. I drove down a bumpy grave road once in a car with an older battery in it, parked and it wouldn't start half an hour later. I think the vibration broke a plate loose and killed the battery.

Generally speaking if you get 5 years from a battery you're doing pretty well. Any less I consider to be sub par and any more I would write off as being ahead of the game.

 

With all this focus on the battery, you forget the cables. Make sure the connection and wires are tight and corrosion free. Check the battery and starter sides.
If the battery tests good, check the voltage at the starter when trying to crank. If you lose more than a volt or two, either the solenoid is bad, ign is not powering the solenoid, or the cables are shot.
Get the charging system checked when you get it running. Slow/weak alternators can cause battery failure. Three complete discharges on a NON-deep cycle battery and it is kaput.

 

I was just playing man.

 

To quickly answer the question: an alarm could certainly drain your battery if it isn't run for awhile. If the truck is run often, then the alarm (or other device) could be failing and drawing high current...try measuring their current, or pulling the fuse for that device and see if it helps. Also, the battery could simply be old or damaged...take it to a local shop to be tested (autozone and the like typically do it for free).

Other info:

Parasitic drain is not only from the computer (or alarm in this case) but by the nature of the battery. I lead-acid battery not plugged into anything will slowly discharge, which is why there are trickle chargers.

A few of the original posts have it right...a battery's voltage isn't the full story, it is its voltage capacity under load. A battery could be reading 12v or more but won't have the capacity to start the truck under a load (i.e. high current draw like the starter). The best way to tell is measure the voltage with the truck off and measure it while it's cranking and again while its running. The voltage will dip a little bit during cranking, but not much...I've never actually measured it, but I'd bet the voltage doesn't dip below 10V. While it's running, it will measure higher because the alternator is supplying overvoltage for charging.

Check out my electrical basics thread for more info (link in signature). Among other things, I explain in laymans terms the electricity/water analogy. Think of a battery as a pool of water. If the pool is the size of a bucket and you punch a hole in the bottom, no matter how fast you try to refill it, the hole will always drain faster keeping the bucket empty. However, if the pool of water is the size of an above ground pool, the same hole won't be enough to drain the pool and it will always be mostly full. This is similar to your battery....the battery's capacity (i.e. size of the pool, typically displayed as cranking amps) is big enough to sustain high current (i.e. the hole) of starting. If the battery is damaged, it acts more like a bucket.

 

Thanks for all the input. I was at work at the time I posted my question. Yes the problem was the fact the truck had been sitting for about 10 days or so. Since the first post I have been driving the truck with battery or charging issues....

Thanks again TW