New 12v dead after one month

[dww]

After my original 12V died about a month ago I replaced it with a new OEM Ford 12V and added a cable for a 12V maintainer. I mostly drive the truck on weekends only, so it does not get a lot of daily use. With the recent cold weather I noticed that the 1a Noco was not staying green so I switched to the 5a one. Mid week I noticed it was not green but thought nothing of it (it’s 5a, it will get it if it is low). Today the truck was dead and the battery was at 3.85V. I jumped it with another 12V and started the truck that then started charging it at 13.44V. I let it run for 20min and turned it off and the battery went back to 5V ish. I removed the battery and have had it on the 5a Noco for the last 8hrs. It look like it might maintain 12V. What could be causing this much drain with the truck off and why would the truck not trigger low voltage charging when it went below 10-11V? The HVB is at 70+%.

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[The Weatherman]

That battery is not likely going to recover. When a 12v lead acid/AGM battery drops to that low a charge it’s cooked.

It may have bad when they installed it or you may have a bad phantom drain.

 

[dww]

That battery is not likely going to recover. When a 12v lead acid/AGM battery drops to that low a charge it’s cooked.

It may have bad when they installed it or you may have a bad phantom drain.

Why isn’t the truck triggering LVB charging though? Is there a monitor module that could have gone bad? If there is a drain beyond what the Noco can do should’t the Truck charger eventually kick in? Adding the Ancel BT monitor is the only thing I have changed since the original battery change out. Would a bad new batter start out Ok and then die a month later? I’ll definitely be taking it back to change out but I want to make sure there is not a third time.

 

[The Weatherman]

The mystery behind when and why the trucks BMS does and doesn’t do what it does is the 64mil question.

 

[Tfarrell73]

Use an OBD reader and check quiescent average drain

 

[chriserx]

Could be parasitic drain, bad battery, etc. You might want to check and verify your noco isn't in 6v mode too. But warranty it out and try again.

 

[RLXXI]

My vote is bad battery. Seen it happen many times and 9 of 10 times once you run a 12v lead acid below 10v for any length of time, it's cooked.

 

[dww]

Could be parasitic drain, bad battery, etc. You might want to check and verify your noco isn't in 6v mode too. But warranty it out and try again.

It’s on 12V AGM. I watch it charge with the Ancel app.

 

[dww]

The 12V battery quiescent avg. is 65ma. from carscanner. The Noco brought it back (outside the truck) and it is holding 12V. I’ve seen on X where there have been several software updates in the last week. I have an aftermarket amp, it will turn off about two minutes after the truck is locked. When I tried to connect the wifi carscanner when the truck was off I noticed at first the amp was off. After the scanner connected I heard the truck click and then noticed the amp was on. I did not unlock the truck. Could the truck be turning it on during a software update and killing the battery? Would there be any record of this if it failed and killed the 12V?

 

[DavidYo]

After my original 12V died about a month ago I replaced it with a new OEM Ford 12V and added a cable for a 12V maintainer. I mostly drive the truck on weekends only, so it does not get a lot of daily use. With the recent cold weather I noticed that the 1a Noco was not staying green so I switched to the 5a one. Mid week I noticed it was not green but thought nothing of it (it’s 5a, it will get it if it is low). Today the truck was dead and the battery was at 3.85V. I jumped it with another 12V and started the truck that then started charging it at 13.44V. I let it run for 20min and turned it off and the battery went back to 5V ish. I removed the battery and have had it on the 5a Noco for the last 8hrs. It look like it might maintain 12V. What could be causing this much drain with the truck off and why would the truck not trigger low voltage charging when it went below 10-11V? The HVB is at 70+%.

Check the voltage output on the maintainer before leaving it on another battery. I had a battery Tender go bad on me years ago and it got stuck on 17V and cooked a brand new battery.

 

[chriserx]

The 12V battery quiescent avg. is 65ma. from carscanner. The Noco brought it back (outside the truck) and it is holding 12V. I’ve seen on X where there have been several software updates in the last week. I have an aftermarket amp, it will turn off about two minutes after the truck is locked. When I tried to connect the wifi carscanner when the truck was off I noticed at first the amp was off. After the scanner connected I heard the truck click and then noticed the amp was on. I did not unlock the truck. Could the truck be turning it on during a software update and killing the battery? Would there be any record of this if it failed and killed the 12V?

Yes, it could, depending on the circuit used for cut on. I have an automation on my phone that runs when my OBDLink connects to my phone I made 2 weeks ago that opens CarScanner automatically, in that time, one day it ran once and on another day it fired up repeatedly, iirc 5 or 6 times. This, despite the fact the truck is 60 feet, a wall and a conex container between each other. Who knows how many times it tries and fails to connect? Unless it is also firing up the DCDC, it could go a long way to explaining the LVB problems in the truck.

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