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thesixcar

2016 sport 2.7L eating batteries

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intermittent issues with the battery/electrical. replaced it in may 2023 with 3 year battery from walmart. lasted ~6 months. replaced with a diehard 3 year battery, and it lasted a few weeks now. yes, i reset the battery management system.

been getting weird warnings; orange wrench for AWD, hill assist, etc. no codes stored and wrench would go away after restarting, but symptoms persist. stiff steering, lane management not working, remote start are some of the issues.

checked voltage and battery was 12.67VDC and 13.6VDC while running. seems normal.

sits overnight, and all was normal yesterday, ran fine. this morning; dead. battery was at ~6VDC.

 

charging it now but this is is driving me nuts. any suggestions???

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What are you using to read codes?

 

Check the charging voltage shortly after a start and it should be +- 14.2v

 

Check for parasitic drain.

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I have found that Diehard branded batteries are not very good.  I have gone through three of them, two in our Ford Edge.  Mine all failed one or two months out of warranty.  (Bought them at the local Sam's Club.)  i think the days of car batteries lasting 5-6 years are gone.  4 years might be a good life.  Including my experience with AGM batteries.

 

And yes, charging voltage usually in the mid 14 volts, at least here.

 

Doug

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charging voltage definitely sounds a little on the low side. Are you testing the voltage with every electrical accessory on?

I don't know which options you have on your sport, but with the heated and air conditioned seats, mine's a 200A unit..

..which i just replaced because the clutch pulley on the nose was freewheeling.

 

however, that does not account for the 6V in the morning.

That is like 99% sure to be a parasitic draw, which could be anything from a bad module to a stuck relay

use that link 1004ron posted above and figure out where it is

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Mid 14s when running is spot on, so your alternator is apparently working. You'll need to do a parasitic draw diagnostic process. There's tons of "howtos" out there on how to find the circuit in question and then figure out what is still "on" when the car is off. I had an Eclipse that had this problem...turned out the dumb glove box switch was misaligned and it wasn't turning off the light. VERY hard to see that and it took me a while to find it. It was supplied with 12v constant power and would kill the battery until I found it. Ensure all the doors are fully closed. Anything added to the car? Dash cam hard-wired into constant power? Radar detector? Etc?

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On 2/5/2024 at 11:52 AM, thesixcar said:

intermittent issues with the battery/electrical. replaced it in may 2023 with 3 year battery from walmart. lasted ~6 months. replaced with a diehard 3 year battery, and it lasted a few weeks now. yes, i reset the battery management system.

been getting weird warnings; orange wrench for AWD, hill assist, etc. no codes stored and wrench would go away after restarting, but symptoms persist. stiff steering, lane management not working, remote start are some of the issues.

checked voltage and battery was 12.67VDC and 13.6VDC while running. seems normal.

sits overnight, and all was normal yesterday, ran fine. this morning; dead. battery was at ~6VDC.

 

charging it now but this is is driving me nuts. any suggestions???

 

14 hours ago, bofus said:

Mid 14s when running is spot on, so your alternator is apparently working. You'll need to do a parasitic draw diagnostic process. There's tons of "howtos" out there on how to find the circuit in question and then figure out what is still "on" when the car is off. I had an Eclipse that had this problem...turned out the dumb glove box switch was misaligned and it wasn't turning off the light. VERY hard to see that and it took me a while to find it. It was supplied with 12v constant power and would kill the battery until I found it. Ensure all the doors are fully closed. Anything added to the car? Dash cam hard-wired into constant power? Radar detector? Etc?

..but his alternator is not making mid 14s..

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1 hour ago, Cerberus said:

 

..but his alternator is not making mid 14s..

...ahh, I see that. I apparently missed it. Yeah, 13.6 is on the low side, but that SHOULD still charge, albeit slower than normal. Would need to see the amps being put out by the alternator as well. If the voltage is that low, then maybe the amps are also low and the system could be drawing more than what the alternator is providing with the car running.

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So I just discovered that the alternator output lead on my 2016 has an amp loop to measure current output.

Using the OBDLinkMx Bluetooth dongle and app, I have been monitoring the output and generally see up to 100A at 14.8-15V after startup. 

This is with a brand new alternator and the biggest battery that fits 

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The alternator output is variable and controlled by the PCM so it may not be constant.

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