12V battery charge

[chuck27p]

I've had my truck for a few years and haven't had a problem, but my 12v battery is testing in the 30% range each morning. I've used a trickle charger for two nights, which went from red to green light, and then the tester told me the battery was good and back to 100%. But a day later, in the morning before I have driven it, it's back down to 25-30%. It seems to charge during the day as I drive.

Is my battery shot? Do I need a new one? I don't want to get stranded. Or is it normal for it to be so low after sitting all night and then charge during the day.

I'm wondering if I should preemptively put in a new battery or if mine is still ok? It's a 2023, so it's almost 2 years old.

Thanks.

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[TaxmanHog]

Trickle chargers aren't the best tool to diagnose a LVB capacity issues

If it's suspect have a comprehensive load test done on it at the Ford Service shop, if they find it's below spec, you might get a warranty swap.

 

[ElectrifyingMe25]

I've had my truck for a few years and haven't had a problem, but my 12v battery is testing in the 30% range each morning. I've used a trickle charger for two nights, which went from red to green light, and then the tester told me the battery was good and back to 100%. But a day later, in the morning before I have driven it, it's back down to 25-30%. It seems to charge during the day as I drive.

Is my battery shot? Do I need a new one? I don't want to get stranded. Or is it normal for it to be so low after sitting all night and then charge during the day.

I'm wondering if I should preemptively put in a new battery or if mine is still ok? It's a 2023, so it's almost 2 years old.

Thanks.

Rockauto for a replacement.

 

[Mal106]

The acessory mode, the app and the key fob kill those little 12v batteries.

I can't think of a reason for the acessory mode in an electric or plug in hybred vehicle. It eats the small 12v battery quickly and can damage it through regular discharging. Batteries are small due to not needing start amperage and are already stressed with communications with the app and key fob. I ran the Lightning battery down using acessory mode and the app and killed a PHEV 12v the same way.

As I understand it, the little battery is charged when the truck is on or being charged. If plugged in and charging complete, I don't know.

I've stopped using the acessory mode and store the fob well away from the truck when not in use.

 

[Maquis]

The acessory mode, the app and the key fob kill those little 12v batteries.

I can't think of a reason for the acessory mode in an electric or plug in hybred vehicle. It eats the small 12v battery quickly and can damage it through regular discharging. Batteries are small due to not needing start amperage and are already stressed with communications with the app and key fob. I ran the Lightning battery down using acessory mode and the app and killed a PHEV 12v the same way.

As I understand it, the little battery is charged when the truck is on or being charged. If plugged in and charging complete, I don't know.

I've stopped using the acessory mode and store the fob well away from the truck when not in use.

Agree 100% regarding accessory mode.

Key fob / phone is only an issue if you are constantly moving in and out of range.

 

[chuck27p]

The acessory mode, the app and the key fob kill those little 12v batteries.

I can't think of a reason for the acessory mode in an electric or plug in hybred vehicle. It eats the small 12v battery quickly and can damage it through regular discharging. Batteries are small due to not needing start amperage and are already stressed with communications with the app and key fob. I ran the Lightning battery down using acessory mode and the app and killed a PHEV 12v the same way.

As I understand it, the little battery is charged when the truck is on or being charged. If plugged in and charging complete, I don't know.

I've stopped using the acessory mode and store the fob well away from the truck when not in use.

I don't use accessory mode much at all. I have in the past, maybe sitting waiting in the truck, camping, or charging, but on a regular basis I do not. Just park it, then drive it.

Maybe earlier usage diminished the battery?

What I'm getting from these responses is I should go replace the battery before I get stuck, and there's no way to know if/when that's going to happen.

Does the dealer have to do it? Is there some reprogramming after, or can I swap it out?

 

[flabrent]

Since CCA's aren't needed, would a deep-cycle marine battery cause any issues with the Lightning?

 

[astrand1]

I don't use accessory mode much at all. I have in the past, maybe sitting waiting in the truck, camping, or charging, but on a regular basis I do not. Just park it, then drive it.

Maybe earlier usage diminished the battery?

What I'm getting from these responses is I should go replace the battery before I get stuck, and there's no way to know if/when that's going to happen.

Does the dealer have to do it? Is there some reprogramming after, or can I swap it out?

Nope. You can easily do it yourself. It’s just like changing a battery in a normal car. Once done you do need to reset the BMS.

 

[Mal106]

Make sure you carry one of those little jump boxes. A very small (cheap) one will do as it takes very little current to start the truck with a weak battery.

 

[ElectrifyingMe25]

Make sure you carry one of those little jump boxes. A very small (cheap) one will do as it takes very little current to start the truck with a weak battery.

You are 100% correct. A little jump box goes a long way. I got stranded on the road one night because of an accident. I was driving an Explorer (ICE). I rand the radio, so I turned on the accessories mode. God only knows what else was running. I guess my battery must have been a little weak. I only ran it for 10 minutes or so. Luckily I tried to start the vehicle before traffic started moving. I got the dreaded "click, click, click" sound.

I didn't have one of those Li-Ion jump boxes. I was dead on the road in a construction zone with one-lane traffic. I was soon to be the cause of backed up and stopped traffic on the interstate. It was now a race to get me jumped vs. the accident clearing ahead of me.

No one around me had jumper cables. Luckily I had a friend who lived 5 miles away who brought an old battery and some jumper cables. He dropped off both next to me in the other lane that was also under construction and one-lane. I got started thanks to his generosity and decent luck. ... the accident was cleared 10 minutes later.

I felt so blessed to get going before traffic started moving.

The next day, I ordered the lithium-ion jump boxes for all my vehicles. And my neighbor friend. The are so worth the cost. I ordered Vtoman from Amazon like the one in the picture. Is a good quality jump starter.

I've used them a couple of times so far in the cold cold winter to get me going. I've never used it on my Lightning Truck. But if I need it I have it there.

Trust me, you don't want to get into the predicament I got into on the interstate that night. The small investment is great insurance.

 

[Tom M]

I don't use accessory mode much at all. I have in the past, maybe sitting waiting in the truck, camping, or charging, but on a regular basis I do not. Just park it, then drive it.

Maybe earlier usage diminished the battery?

What I'm getting from these responses is I should go replace the battery before I get stuck, and there's no way to know if/when that's going to happen.

Does the dealer have to do it? Is there some reprogramming after, or can I swap it out?

Reset F-150 12v BMS
1. Press start button, but do not start the truck (foot not on brake pedal)
2. Flash high beams 5 times and then press the brake pedal 3 times.
3. Wait for the battery indicator on the dash to flash; it can take a few seconds.

 

[Adventureboy]

How are you measuring the 12V SOC in the morning? The 12v should be at 100% at the end of your HVB charging cycle, so if your charge cycle ends at say 2 am and it is dropping to 25-30% by say 8 am, it probably means a replacement is in order. As @TaxmanHog said, only a proper capacity test can tell you that for sure.
The little 12V AGM batteries on our Lightnings take a beating daily. Many of them are at the end of their life, at or before 3 years. Mine has been replaced once already under warranty.

 

[chuck27p]

How are you measuring the 12V SOC in the morning? The 12v should be at 100% at the end of your HVB charging cycle, so if your charge cycle ends at say 2 am and it is dropping to 25-30% by say 8 am, it probably means a replacement is in order. As @TaxmanHog said, only a proper capacity test can tell you that for sure.
The little 12V AGM batteries on our Lightnings take a beating daily. Many of them are at the end of their life, at or before 3 years. Mine has been replaced once already under warranty.

I'm using this tester and I've been testing it at various times throughout the day. I charge about 1x per week, and I don't think I've tested after charging it. I'm charging tonight, so I can check it in the morning. Thanks.

 

[B177y]

I'm using this tester and I've been testing it at various times throughout the day. I charge about 1x per week, and I don't think I've tested after charging it. I'm charging tonight, so I can check it in the morning. Thanks.

When you use your trickle charger are you attaching it to the jump posts under the passenger side frunk trim or directly to the battery posts at the center-rear of the frunk?

If you attach the charger directly to the battery, you could bypass the BMS and you'll get all sorts of weird 12 volt issues.

You should be using the jumper posts to charge. If you are already doing that, then I agree with the other suggestions that you need to get a load test and possibly new 12 volt battery.

 

[RickLightning]

You need to test it 30 minutes, or more, after opening the frunk, and approach without fob or PaaK.

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