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Horn draining battery?

IslanderOffRoad

IslanderOffRoad

NAXJA Forum User
NAXJA Member
Location
Houston, Tx
Last month I went back to Ca, tried to fire up my Jeep to go meet some people for lunch, and the battery was completely dead.

Jumped it, started a-ok, but died again shortly thereafter (didn't run it long enough) so I pulled the battery and put it on a trickle, it held a charge.

Anyways since then I headed back to Tx, left the battery out, but I'm trying to figure out what may have drained my battery. It sat for a couple months, but it spends most of its time sitting, and has never had this problem before.

Over winter break I fixed the horn contact in the column, which had been broken for a while. The kit I got was a "universal" for gm columns, and you had to cut the horn plunger to fit your vehicle's application.

If that were slightly too long, and making contact, could it cause battery drain without making the horn go off?

Want to know if thats the best place to start figuring out my drain issue.
 
I think a horn will either be off or on, and if it's on you'll know it.
Be sure the battery is fully charged and the water level is up before you let it sit.
I would probably disconnect the battery before heading back to school, or have someone drive it around occasionally.
If it still doesn't hold a charge next time it might be time for a new battery.
 
Have the battery Load Tested at the auto parts store or repair shop. The battery may simply have failed and won't hold a charge.

Numerous threads explain how to use a Volts/Ohms meter to locate an excessive power drain.
 
I'm sure there could be a scenario where your horn could have a coil going bad, in it still will draw current but make no noise when you push the button. But if your horn is good, and the problem is in the wiring, then there's really no way. Horns are usually an EXTREMELY simple circuit. If you have current shorting to ground, you would blow a fuse.

If it's a serviceable battery, like said above make sure you're electrolyte is full. Also make sure the case is clean, and free of any spray. Advance auto or some local store should be able to do a load test. Even the midtronics conductance tests are decently accurate. It could the battery just can't hold a deep charge.

If you have access to a multimeter with an ammeter, check your IOD current. Usually the spec is somewhere around 50mA or less. You'll have to give it a good ten minutes for all your modules and such to turn off, but you'll be able to see if something is pulling excess current and draining your battery.
 
All good advice from the others.

There is always going to be a small parasitic draw--radio memory, PCM, so for extended storage periods you should disconnect the battery, and hooking it up to a "maintenance charger" is a good idea.

Note that non-sealed batteries can accumulate enough conductive crap on the top of the battery's case to allow for a slight current draw, so keep the top of the battery clean.
 
Thanks guys.

The battery is a non-serviceable Optima red top. I pulled it from the Jeep when I was home in March and found it dead, haven't put it back in. Should be ok... its not very old. But we'll see when I get home in 2 weeks.

My dad claimed he had been starting it every couple weeks, but I may just need to keep it not hooked up; the Jeep is street parked at my parents, so I can't really run a cord to it for a maintenance charger.
 
Pull the battery, set it on a board in the garage, hook up the maintenance charger, plug in--next time you are home you are good to go in 10 minutes, and that includes walking from the garage to the street.
 
My dad claimed he had been starting it every couple weeks
Click to expand...

This is a common misconception a lot of people think helps charge the battery. Really all it does is kill it more, and mask it by putting a surface charge on.

By starting the car, you're draining the battery. The FASTEST way at that. Then you let it run for 10-15 minutes or so at idle. At idle, the alternator works like crap, almost no output. If it was a Honda, they shut the dang thing off at idle. So you're really only putting this shallow charge on it. If you're alternator can't keep up with the demands of the PDC (at idle), it starts dipping into your battery to suffice. That's why all alternator tests are done at/above 2000 rpms, and all state-of-charge tests are done with surface charge removed.

I went to a Ferrari dealer in CA over the winter, and when I walked in they were all running and revved at about 1500 rpms. I asked the attendant wtf was going on. He said once a week they start them all up, put pedal depressors on them, and run them at a high rev for half an hour to charge the battery. Sounded like a space ship was about to take off. And when they went to turn them off, they would redline each one. THAT was fun to hear :)

-So long story short, disconnect your battery if it's going to sit
-Don't start it and just let it idle
-Put a trickle charger on it if you can
 
DanMan2k06 said:
This is a common misconception a lot of people think helps charge the battery. Really all it does is kill it more, and mask it by putting a surface charge on.

By starting the car, you're draining the battery. The FASTEST way at that. Then you let it run for 10-15 minutes or so at idle. At idle, the alternator works like crap, almost no output. If it was a Honda, they shut the dang thing off at idle. So you're really only putting this shallow charge on it. If you're alternator can't keep up with the demands of the PDC (at idle), it starts dipping into your battery to suffice. That's why all alternator tests are done at/above 2000 rpms, and all state-of-charge tests are done with surface charge removed.

I went to a Ferrari dealer in CA over the winter, and when I walked in they were all running and revved at about 1500 rpms. I asked the attendant wtf was going on. He said once a week they start them all up, put pedal depressors on them, and run them at a high rev for half an hour to charge the battery. Sounded like a space ship was about to take off. And when they went to turn them off, they would redline each one. THAT was fun to hear :)

-So long story short, disconnect your battery if it's going to sit
-Don't start it and just let it idle
-Put a trickle charger on it if you can
Click to expand...

Exactly, good summary! :patriot:
 
joe_peters said:
Pull the battery, set it on a board in the garage, hook up the maintenance charger, plug in--next time you are home you are good to go in 10 minutes, and that includes walking from the garage to the street.
Click to expand...

Thats the current plan.
 
My XJ cigarette lighter is only "hot" with key-on, so the solar one I use for this purpose has a wire run through the firewall connected to the batt.

2 cents. Otherwise the solar panel is working for me.
 
cj5wagomando said:
My XJ cigarette lighter is only "hot" with key-on, so the solar one I use for this purpose has a wire run through the firewall connected to the batt.

2 cents. Otherwise the solar panel is working for me.
Click to expand...

I saw a 2-pack of those on sale sometime back at Costco, thought about it but ended up not buying them--kind of wish I had now.
 
Trickle charged, started fine.

Will see how it does tomorrow now that the battery is hooked back up.
 
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