Another Parasitic drain thread :(

[Tim C]

Ok, so I’m still having a battery drain issue. After a couple of days of sitting, the battery would drain to the Point where the truck would not start. I’ve just put a new battery in.

It’s a 2011 Ram 1500 with the Hemi.

I’ve done the diagnosis as mentioned in many threads:
Jumper the hood switch.
Connect the multimeter between negative post and negative wire clamp.
Close/lock doors.
Let everything settle for an hour.
Watched the multimeter for 15-20 minutes (probably longer) for spikes (There were none).
After that time, amp draw is consistently bouncing (every second or so) between .013 and .017 amps.
Pulled the fuses one by one. The only thing that made a difference was J13 - IOD Main. Pulling that settled the amps down to a steady .010 amps.

So... a couple of questions. Is .017 amps enough to drain the battery in 2-3 days? The second question, if it really is the IOD, what is my next step in the diagnosis?

****Update:

I’ve done a more thorough investigation today and have better information.

I hooked up my meter in the same way but his time I put a GoPro on it. I was able to better review the results. Over the course of about an hour and twenty minutes I had 5 spikes that lasted between 45 and 55 seconds. It spikes to around 2 amps, hovers around between 1.8 and 1.5 amps for most of the time then drops to 1.0 amps for a second or two before dropping back to .013 to .017.

There is no consistency in the timing of the spikes. The second spike started after 3 minutes from the first. The next spike started 8 minutes later, the next 9 minutes. From the last spike to when my camera battery died it was 44 minutes.

Any suggestions on where to go from here?

Any help would be super appreciated!

Thanks!

 

[ric221]

I know you said you checked all fuses. But make sure to check the radio fuse. I say this because a had a 10 that had the same problem. Turns out the radio had a short that pulled power even when the ignition was off.

 

[Tim C]

Thanks Ric. I’ll check that out again tomorrow. But...I left the meter connected since I posted the question until just now. Going back out to look at the reading it has dropped down to .008 amps. Hmm??? I’ll update my question with this information. I’m going to do the whole thing again tomorrow.

 

[Jeepwalker]

.008 seems real low to me. If it stays. Does your meter have a 'max' function you can reset when it gets that low and you can leave it a while to see if it jumps when you're not looking?

 

[Jeepwalker]

According to this calculator, at .008A draw, your battery (assuming GP 94R, 80AH) would go 10,000 hrs ...about 1yr and 1 month till dead. Unless I'm reading things wrong..

Battery Life Calculator | DigiKey Electronics

DigiKey's battery life calculator uses battery capacity (mAh) and device consumption (mA) to calculate estimated hours of battery life.

www.digikey.com

 

[Tim C]

Thanks for that info @Jeepwalker . I’ll keep that handy.

I’ve done a more thorough investigation today and have better information.

I hooked up my meter in the same way but his time I put a GoPro on it. I was able to better review the results. Over the course of about an hour and twenty minutes I had 5 spikes that lasted between 45 and 55 seconds. It spikes to around 2 amps, hovers around between 1.8 and 1.5 amps for most of the time then drops to 1.0 amps for a second or two before dropping back to .013 to .017.

There is no consistency in the timing of the spikes. The second spike started after 3 minutes from the first. The next spike started 8 minutes later, the next 9 minutes. From the last spike to when my camera battery died it was 44 minutes.

Any suggestions on where to go from here?

 

[south7west]

I know it isn't readily available for most, but I have had great luck in using a thermal imager on the fuse block to find parasitic draws in the past on other vehicles. It allows me to see which fuses heat up more than others while the vehicle is off, and from there check wiring diagrams and start testing the appropriate circuit

 

[Jeepwalker]

...I have had great luck in using a thermal imager on the fuse block to find parasitic draws in the past on other vehicles.

That's a fantastic idea!
BTW

 

[csuder99]

Something is waking up the modules on the CAN bus causing the periods of higher current draw. These problems are a pain in the you-know-where to track down. Best is probably to disconnect modules one by one and see if the bus stays quiet. Then you need to figure out if the module itself has an issue or if something causes it to wake up and send messages. I'd start with the BCM and anything related to the radio.

 

[BossHogg]

A resting vehicle will show periodic current increases for a short period of time, like around a few hundred milliseconds and then again in a few hundred milliseconds. This is caused by the RF circuit waking up looking for the possibility of its FOB sending a command. These current peaks should be at or under 280ma.

My approach to finding the cause would be to start pulling fuses, one at a time until I found the offending circuit. Keep in mind the circuit you find may be collaterally related.