Chasing a battery drain on my 2500

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MichaelSE

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Hi all, I have a '10 2500 that has gone through 3 batteries in the past 3 years. Something is draining them and I haven't been able to figure it out. The battery will get weaker and weaker (slower starts), and eventually so dead that my jump box doesn't even jump it. I typically only drive it on the weekends, sometimes every 2 weeks, though I recently took it on a trip where I drove it every day for a week and by the end of the trip it was still starting weak. No aftermarket radio, all stock.

Here's what I've done so far..
- Verified alternator charging battery (at least according to Autozone)
- Always unplug accessories from cigarette lighter ports, whether they're switched or unswitched - still drains
- Checked all the grounds I could find - all look good and are tight
- Sat in it for an hour with the engine off to see if anything turned on - didn't hear anything, or see any lights


Any other ideas? I have a basic multimeter, so if there are any Youtube videos on how to check other things, I can do that. Thanks in advance.
 

2016Dom

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Use the multimeter setting it to detect amps and hook it between the battery ( don't go over the AMPs for the meter) and the cable so you can see the draw of power and start pulling fuses until the draw stops.

EDIT : SEE OTHER POST
 
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mikez71

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Did you remove alternator for autozone? Or did they test in truck?

You could try unplugging the RVC sensor that your negative battery cable goes through.
If it was bad or installed backwards, it might affect charging somewhat.

Was the issue for at least 1 person before..
 
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Fless

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Don't use the "pull the fuses" method, since it can wake up modules during the test; there's an easier way. There are lots of good YouTube videos on diagnosing parasitic draw. Here's one:


You may need to pull fuses if you get to a draw on the J-case fuses, but try the voltage drop measurement first.

For mini fuses here's the chart to convert voltage drop to estimated current draw: https://m.roadkillcustoms.com/wp-content/technical-pdf/Mini Fuse Voltage Drop Chart.pdf Any fuse that has a voltage drop is carrying current. Isolate the circuit, then diagnose it. You're looking for a final draw, fully asleep, for under 50 mA (0.050 A), but that vehicle should easily go below 25 mA if all is well. Pay close attention to aftermarket remote starters, alarms, etc.
 

GMCnewbee

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We just replaced the factory radio and amp in my Son's 2007 Dodge Charger. The battery had been draining and the radio had been cutting on and off. Radio shop said that it was a bad amp that was causing the problem. I didn't know that was a "thing". I thought that with the ignition off that the radio was also off. Nope!
 

mikez71

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Frickin computer modules on everything...
That don't do ANYTHING I need or want. I hate it!

Every new car beeps nonstop at me for the first minute of driving..
I don't drive my girlfriends car because I'm afraid I'll start punching it.
I feel sorry for the kids who are growing up with this BS..
 

ReaperHWK

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How many amps is it pulling when the car is off?

I’d Measure that first.

When you get the draw then you can start disconnecting suspect circuits and see the amperage drop (or not).

These clamp meters are easy to use and they’re cheap now.


Also I assume you did basic troubleshooting on the charging system right? Your getting over 14V on the battery when the truck is on?
 

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