Dead battery
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6th Gear
Joined: Jun 2025
Posts: 6
Likes: 1
Dead battery
I have 2019 Lariat Diesel. Bought it new in early 2020. OEM batteries lasted until October 2024. I replaced with sealed lead acid from Walmart (we were traveling and they were nearby). We returned from our winter trip in late March 2025 and we had no problems at that point. Went to start it April 16 as it had been sitting a few weeks and batteries were totally dead - read 2.5 volts. Took them to Walmart who diagnosed them as bad a replaced under warranty. Installed them, drove the truck once the second week in May with no problems. June 11 was going to drive again but it was dead, batteries read 2.5 again. A few days earlier I was in the truck, opened with remote but I did not start the truck. Put a charger on and won't charge above 11.5, lights on charger indicate it could a bad battery. I spoke with my long time mechanic who said he doubts the truck is causing the problem. Truck is totally stock. Anyone have this happen, any thoughts?
Thanks.
Thanks.
Hotshot
Joined: Jul 2013
Posts: 14,298
Likes: 2,197
I had this problem on my 2019 and after going to battery set number three I ran an extra black battery cable from the pax side battery negative to the drivers side battery negative and since doing that everything has been fine.
My theory….pax side grounds to the body while drivers side grounds to the frame ….i think the pax side charging circle is poor and I was in essence just running off one battery…the drivers side…and in between uses the pax side was draining the drivers side.
My theory….pax side grounds to the body while drivers side grounds to the frame ….i think the pax side charging circle is poor and I was in essence just running off one battery…the drivers side…and in between uses the pax side was draining the drivers side.
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6th Gear
Joined: Jun 2025
Posts: 6
Likes: 1
I had this problem on my 2019 and after going to battery set number three I ran an extra black battery cable from the pax side battery negative to the drivers side battery negative and since doing that everything has been fine.
My theory….pax side grounds to the body while drivers side grounds to the frame ….i think the pax side charging circle is poor and I was in essence just running off one battery…the drivers side…and in between uses the pax side was draining the drivers side.
My theory….pax side grounds to the body while drivers side grounds to the frame ….i think the pax side charging circle is poor and I was in essence just running off one battery…the drivers side…and in between uses the pax side was draining the drivers side.
I know next to nothing about vehicle electrical issues. Since the first set of batteries lasted over four years, and the second only a couple months, I am not sure if that is my problem. Thanks for your input.
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6th Gear
Joined: Jun 2025
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I plan to take them in the morning. Not feeling very secure about their batteries at this point. We travel a lot, at times in remote areas with no cell service. Would hate to have them die on me there. One set lasted 6 months, one 2 months.
Mountain Pass
Joined: Sep 2014
Posts: 217
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Four dead batteries in a short period of time would make me think the parasitic draw is more than normal.
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Mountain Pass
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Lead acid batteries can be damaged fairly easily. They are designed to be charged once they go much below 12V, and if they are not, and continue to be drained, they can be permanently damaged. The fact that the batteries are reading only 2.5 volts indicates they are likely to have been damaged. It's highly likely the problem is parasitic loads and not defective batteries, since this has happened twice in a row, and it is happening after the vehicle has been sitting for a while.
As a temporary workaround, you could connect a trickle charger (low current battery maintainer) when the truck is not being used.
As a temporary workaround, you could connect a trickle charger (low current battery maintainer) when the truck is not being used.
5th Wheeling
Joined: Aug 2023
Posts: 27
Likes: 19
Unlikely after batteries already swapped. More likely excess parasitic, not enough driving, bad grounds, or bad charging system. Test parasitic and report back.
Logistics Pro
Joined: Jan 2010
Posts: 4,129
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I don't recall what years had what batteries, but if you originally had AGM batteries you may want to go back to those (I know, you're biting a bullet). I also believe that if you change between styles (AGM vs Lead Acid) you need to change something in the programming of the truck so the BCM/BMS knows that the batteries were changed. Going back to AGM batteries may solve all your issues here if you don't have access to something like ForScan so you can make the alterations.
Laughing Gas
Joined: Aug 2021
Posts: 916
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I don't recall what years had what batteries, but if you originally had AGM batteries you may want to go back to those (I know, you're biting a bullet). I also believe that if you change between styles (AGM vs Lead Acid) you need to change something in the programming of the truck so the BCM/BMS knows that the batteries were changed. Going back to AGM batteries may solve all your issues here if you don't have access to something like ForScan so you can make the alterations.
I think my 2022 was the last year for standard wet cells. I upgraded to AGMs last year and they have been great. Hasn’t gone into sleep mode since. My 2022 has the BMS so I needed forscan to change the battery type and reset the BMS.
At 2.5Vdc I would look hard for a parasitic drain on your battery. I would also check your charging voltage to make sure that your alternator is working properly.
Bob
Tuned
Joined: May 2010
Posts: 499
Likes: 132
From: Pleasanton, CA
Replace both batteries then keep a close eye on the voltage level perhaps every few days, keep a log. If you start to notice a voltage drop on either battery then bring it in to your favorite auto electric shop or dealer to have it diagnosed.
Good luck,
Mike
Good luck,
Mike
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