Parasitic draw..... maybe not?

[mpyusko]

I'm facing what appears to be a parasitic draw. After my rig sits for only a few days (like 3 or 4) the battery is dead.

At first I thought it was the battery, but I replaced it with a brand new 1000 CA. I should have plenty of power, but it still dies. Later I was camping (away from the city lights) and I noticed my vanity mirror lights were on. So I unplgged them from inside the headliner. I enabled the courtesy light defeat switch so no lights go on when I open the doors. I checked my under-hood light and removed the bulb, I unplugged the work light. The only things that should be drawing power are the computer and the a phone charger (I use a GPS speedometer on an old Droid because my speedo is between 5 to 15 off when driving between 30 and 65 MPH) Combined they should only draw 1 amp. The discharge rate I'm looking at, I should be finding a draw of around 15A continuous. A clip-on meter only shows ~2ish I figure for the stereo. Even at 2 Amps, it should be more than a week before I notice a drop in voltage, but this thing is stone dead 0V when I go to crank it after 4 days (not sure how long it actually took to die). No beep, no click, deader than Jacob Marley.

But is it really a parasitic draw? When the truck is running, it shows 14V on the gauge. But could the alternator be 'working' and not charging the battery? For instance, the last time I drove it, it was raining, so I had the lights, wipers and heaters running. The voltage was good the entire time on the gauge, but could it be I was actually running off the battery and the alternator wasn't charging it. I need to get this tracked down because the weather is turning cold and the last thing I need is a dead battery on a cold night with a truck full of kids. (BTW, Yes.... The headlight and wipers were turned off when I found it dead. I have a spare 1000CA battery I keep in the garage on float, but when I pack it up to take it with me I can only get 2 jumpstarts out of it, against a dead battery in the truck... the 454 takes a lot of juice to crank.)

Ideas?

Edit: I mis-wrote. The the initial current draw is 1.25A when the circuit is connected through the meter. After about 5 seconds it drops to 0.2A not 2A like I previously mentioned. I can trickle charge it at 2A and it it was actually drawing that sitting, it would not charge.

 

[Ruger_556]

If the battery and the alternator are good... And everything hinges on this 0.2 amps will kill a battery in not as long as you think.

About 50 milliamps (0.05 amps) is the most parasitic draw you want to have. To find the draw open your fuse panel... Range your meter to millivolts (mV) and test across the nubs on the back of the fuses. If the circuit is drawing amperage it will display a number (Probably be very close to zero but more than just the interference from your cell phone etc...) on the meter (You are testing for a voltage drop by doing this. According to Kirchoff's law if there is current flow there is a voltage drop). Hence if something on that circuit is powered up there will be a voltage drop across the fuse. Once you find the fuse you know the circuit that the problem is in.

Some other things... Do you have an amp in this truck? If so I would immediately suspect that.

Alternators can fail but still charge the battery if one of the diodes shorts out. If that happens the alternator will draw the battery down while shut off but still charge "somewhat normally"... Usually has an AC ripple.

When you say zero volts is it actually at zero? 10.5 volts is completely dead. I would make very... very sure that battery is good.

Are you leaving your phone plugged in while the truck sits?

 

[Ruger_556]

Also, if you have access to a clamp-on meter use that. Putting a meter inline will reset computers, timers, etc...

 

[Ruger_556]

One more thing to check is your battery connections... If they're corroded the battery voltage doesn't have to drop far for it to be dead in the water.

One quick test you can do is a light of some nature. Any non-LED light really... Test light, brake light bulb, not sure I'd use a headlight considering how small the draw is. On bigger draws (4 amps +) I use a sealed beam headlight with jumper wires clipped on. Use jumper wires in between the ground cable and the negative post on the battery... Then pull fuses until it goes out

 

[mpyusko]

If the battery and the alternator are good... And everything hinges on this 0.2 amps will kill a battery in not as long as you think.

About 50 milliamps (0.05 amps) is the most parasitic draw you want to have. To find the draw open your fuse panel... Range your meter to millivolts (mV) and test across the nubs on the back of the fuses. If the circuit is drawing amperage it will display a number (Probably be very close to zero but more than just the interference from your cell phone etc...) on the meter (You are testing for a voltage drop by doing this. According to Kirchoff's law if there is current flow there is a voltage drop). Hence if something on that circuit is powered up there will be a voltage drop across the fuse. Once you find the fuse you know the circuit that the problem is in.

Some other things... Do you have an amp in this truck? If so I would immediately suspect that.

Bone stock (except the tires and rims).

Alternators can fail but still charge the battery if one of the diodes shorts out. If that happens the alternator will draw the battery down while shut off but still charge "somewhat normally"... Usually has an AC ripple.

I went out again after I posted. I got the same result as before, current drain was 0.13A to 0.2. I went inside it and unplugged my phone chargers and tried again, 0.01A. The truck fired up (as expected, it was fully charged) and the volts read 14.95V. After it had been idling a few minutes the voltage dropped to 14.3V. Using T = C / I [SUP]n[/SUP] I should get about 1000 hours with a 0.2A draw. C = 1000, I = 0.2, n = 1.1 (Estimated efficiency of a new battery)

When you say zero volts is it actually at zero? 10.5 volts is completely dead. I would make very... very sure that battery is good.

Dead. Stone dead.... etc. When I turned the key, the volt gauge went straight to zero (the black space all the way to the left). no buzzes, no clicks, absolutely dead. Even at 10.5, the ignition and computer would shut down, but it would still click the solenoid, maybe even grunt a little. (Some days I miss my old '83 caprice. 305, 4bbl, ... no computer! I could snap the key so quick, it would start and you wouldn't even hear the starter.)

Are you leaving your phone plugged in while the truck sits?

Yes, but this is no different than any other vehicle I have. The all have phone chargers in them, plugged in and lighting up. I just moved one of my cars the other day and it had been sitting for several weeks with a charger plugged in.

 

[mpyusko]

Also, if you have access to a clamp-on meter use that. Putting a meter inline will reset computers, timers, etc...

Nope, only have an inline. I don't care about resetting the computer, and the radio stores the stations (oddly, not the time).

One more thing to check is your battery connections... If they're corroded the battery voltage doesn't have to drop far for it to be dead in the water.

One quick test you can do is a light of some nature. Any non-LED light really... Test light, brake light bulb, not sure I'd use a headlight considering how small the draw is. On bigger draws (4 amps +) I use a sealed beam headlight with jumper wires clipped on. Use jumper wires in between the ground cable and the negative post on the battery... Then pull fuses until it goes out

yeah, My Jeep had a problem a while back where anytime it rained there was enough moisture in the air and oxidization on the pos term/cable that I would have to disconnect and clean them in order for it to start. That was the first thing I checked, forgot to mention, and discounted.

 

[Ruger_556]

I went out again after I posted. I got the same result as before, current drain was 0.13A to 0.2. I went inside it and unplugged my phone chargers and tried again, 0.01A. The truck fired up (as expected, it was fully charged) and the volts read 14.95V. After it had been idling a few minutes the voltage dropped to 14.3V. Using T = C / I [SUP]n[/SUP] I should get about 1000 hours with a 0.2A draw. C = 1000, I = 0.2, n = 1.1 (Estimated efficiency of a new battery)

Yes, but this is no different than any other vehicle I have. The all have phone chargers in them, plugged in and lighting up. I just moved one of my cars the other day and it had been sitting for several weeks with a charger plugged in.

Cranking Amps (CA) is different from Amp Hours (Ah) and may be messing up your calculation there. The gauge on the dash is not an accurate way to check battery voltage (Check it with your meter when it's "dead") If it is actually close to zero you either have a much bigger draw than you're seeing on your meter (Find another to double check against... or you have a failing battery). If the battery is still over say 9.5 volts and you get nothing whatsoever (Lights, solenoid click, etc...) then check your battery cable connections all the way to the starter solenoid. A poor connection becomes no connection if the battery voltage drops a little. Same thing happened on a Ford I used to have. Let it sit for a few days and you would have no lights (Dash or anything else), no click, absolutely dead. But the battery was still just over 12 volts... It ended up being a corroded connection at the starter relay on the fender.

I'd be wondering about that phone charger... 100 mA is a lot just to run that LED light although it shouldn't kill the battery

 

[Bearcat91]

I had an issue where my truck kept dying. Had Auto zone check it and it was bad. Had a bad cell In it. Got a new one. Still did it. The NEW battery they gave me had a bad cell too so I say get the battery checked out again

Sent from my DROID BIONIC using Tapatalk 2

 

[mpyusko]

It ended up being a corroded connection at the starter relay on the fender.

I'll check that. Other ends are harder to dig for.

I'd be wondering about that phone charger... 100 mA is a lot just to run that LED light although it shouldn't kill the battery

"Made in China"

 

[Ruger_556]

I had an issue where my truck kept dying. Had Auto zone check it and it was bad. Had a bad cell In it. Got a new one. Still did it. The NEW battery they gave me had a bad cell too so I say get the battery checked out again

Sent from my DROID BIONIC using Tapatalk 2

^^^ Yes! ^^^

Everything is dependent on that battery being good. New batteries can fail Easy way to test battery is to disable your truck from starting (Pull INJ fuse) and crank for 15 seconds with your meter hooked up. Should not fall below 9.5 volts.