Low 12v Battery Message

[Old Bear]

I watched a video which says the car keeps pulling 18 AMP from the battery just sitting there. There are so many systems in the car. Here is the video.
Ford BMS Battery Monitoring System: How it Works and How to Properly Charge Your Battery!

At the end of that video, you should see where he clearly points out that the 18 amp draw was with the power/key ON but not started. That obviously has all electronics turned on. Once the power/key is OFF and you wait about 75 minutes (key fob away from truck!), all of the electronics turn off and power draw should drop to around a half an amp.

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[scott011422]

I seem to be at a loss. Everything I test looks good.

If I pull the battery and charge it. 18hrs @ 32 degrees later the battery is still fully charged at 12.74v

If the battery is in the truck and fully charged, voltage is 11.91 after 18hrs @ 32 degrees.

Using a 100amp resistive battery tester, the battery passes, Its on the low end of good, but passes.

Draw on the battery after 10min is 1.7 Amps.

Draw on the battery after 120min is only .01 Amps. So no load from the truck in sleep mode.


Experience leads me to think that i'm low on capacity, but there is no test for that with automotive batteries., at a 40% charge, (11.91V) it take a 3.5a charger a touch less than 2 hours to fully charge this battery. 800cca with 140 reserve should take the better of 25hrs at 2amps. Its just not taking much power to charge it. And with low capacity, it doesn't take much load to significantly drop resting battery voltage.

I'm thinking of just biting the bullet and throwing in a new battery. What do you guys think?

 

[Handle]

I seem to be at a loss. Everything I test looks good.

If I pull the battery and charge it. 18hrs @ 32 degrees later the battery is still fully charged at 12.74v

If the battery is in the truck and fully charged, voltage is 11.91 after 18hrs @ 32 degrees.

Using a 100amp resistive battery tester, the battery passes, Its on the low end of good, but passes.

Draw on the battery after 10min is 1.7 Amps.

Draw on the battery after 120min is only .01 Amps. So no load from the truck in sleep mode.


Experience leads me to think that i'm low on capacity, but there is no test for that with automotive batteries., at a 40% charge, (11.91V) it take a 3.5a charger a touch less than 2 hours to fully charge this battery. 800cca with 140 reserve should take the better of 25hrs at 2amps. Its just not taking much power to charge it. And with low capacity, it doesn't take much load to significantly drop resting battery voltage.

I'm thinking of just biting the bullet and throwing in a new battery. What do you guys think?

One other consideration may be the health of the auxiliary battery since it is wired in parallel with the under the hood 12v.

 

[Snakebitten]

I seem to be at a loss. Everything I test looks good.

If I pull the battery and charge it. 18hrs @ 32 degrees later the battery is still fully charged at 12.74v

If the battery is in the truck and fully charged, voltage is 11.91 after 18hrs @ 32 degrees.

Using a 100amp resistive battery tester, the battery passes, Its on the low end of good, but passes.

Draw on the battery after 10min is 1.7 Amps.

Draw on the battery after 120min is only .01 Amps. So no load from the truck in sleep mode.


Experience leads me to think that i'm low on capacity, but there is no test for that with automotive batteries., at a 40% charge, (11.91V) it take a 3.5a charger a touch less than 2 hours to fully charge this battery. 800cca with 140 reserve should take the better of 25hrs at 2amps. Its just not taking much power to charge it. And with low capacity, it doesn't take much load to significantly drop resting battery voltage.

I'm thinking of just biting the bullet and throwing in a new battery. What do you guys think?

Wow, thanks for the thorough testing!

Can I ask how you were measuring the Amp draw when the truck was off? (both after 10 minutes and 120)

Since we don't know how long the 1.7amp draw actually lasted, how long would it take for that draw to drop the SOC of the battery in a meaningful amount?

 

[scott011422]

Wow, thanks for the thorough testing!

Can I ask how you were measuring the Amp draw when the truck was off? (both after 10 minutes and 120)

Since we don't know how long the 1.7amp draw actually lasted, how long would it take for that draw to drop the SOC of the battery in a meaningful amount?

I disconnected the negative lead and connected my Fluke 177 inline between the battery and the negative lead.

Its had to say since automotive batteries are not rated in MaH. But take this into account. The battery is rated with a 140 reserve. That means the battery is capable of supplying a 25 amp load for 140 min before the battery reaches 10.5v. So at 1.7 amps, it would take roughly 37 hours to reach the same 10.5, or 18.5 hrs to 11.6v? Give or take?

 

[Snakebitten]

I disconnected the negative lead and connected my Fluke 177 inline between the battery and the negative lead.

Its had to say since automotive batteries are not rated in MaH. But take this into account. The battery is rated with a 140 reserve. That means the battery is capable of supplying a 25 amp load for 140 min before the battery reaches 10.5v. So at 1.7 amps, it would take roughly 37 hours to reach the same 10.5, or 18.5 hrs to 11.6v? Give or take?

Perfect.
I don't know how you couldn't trust that reading then with that method.
Again, I was just curious.

And like you, I don't have my head around the inconsistent drain from one night to another on my 12V & High Voltage batteries in my Powerboost.

I can go 2 or 3 nights in a row and both batteries SOC will be pretty much what they were the next morning. And then suddenly, randomly, I will have a morning where they obviously got taxed considerably the previous night.

I would love to find a self powered Bluetooth based tool that would allow me to monitor the 12V draw with an app. Something similar to what your Fluke is being used for but viewed remotely.

 

[Handle]

Perfect.
I don't know how you couldn't trust that reading then with that method.
Again, I was just curious.

And like you, I don't have my head around the inconsistent drain from one night to another on my 12V & High Voltage batteries in my Powerboost.

I can go 2 or 3 nights in a row and both batteries SOC will be pretty much what they were the next morning. And then suddenly, randomly, I will have a morning where they obviously got taxed considerably the previous night.

I would love to find a self powered Bluetooth based tool that would allow me to monitor the 12V draw with an app. Something similar to what your Fluke is being used for but viewed remotely.

I bought this a couple weeks ago to attempt to do it. But right now my battery(s) are behaving so haven’t set it up for an overnite test yet.

https://www.amazon.com/dp/B08JTPLL6B?ref=ppx_yo2ov_dt_b_product_details&th=1

 

[Henfield]

I test my batteries periodically just to see how they are doing. The F150 is too new to have been tested so far and its not given me any cause for concern.

 

[Snakebitten]

I bought this a couple weeks ago to attempt to do it. But right now my battery(s) are behaving so haven’t set it up for an overnite test yet.

https://www.amazon.com/dp/B08JTPLL6B?ref=ppx_yo2ov_dt_b_product_details&th=1

Thanks!!

I wish it cost 5X's that for some reason. ?

 

[scott011422]

Odd glitch this morning. Is this a battery problem? I didn't get any messages. No, I haven't replaced the battery yet.

Truck would not start with FordPass app. Started fine with fob. Zone lights didn't work through app. Approach lights didn't work. Bed lights didn't work when I pressed the button inside the bed. All interior lights did not work when I opened the doors. All of this with the truck running with remote start. Once I pressed the start button, Everything worked as it should.

I remote start every morning for a few min to get some oil moving and heat in the engine before driving off. Never had any of this happen before.

 

[towpro]

Odd glitch this morning. Is this a battery problem? I didn't get any messages. No, I haven't replaced the battery yet.

Truck would not start with FordPass app. Started fine with fob. Zone lights didn't work through app. Approach lights didn't work. Bed lights didn't work when I pressed the button inside the bed. All interior lights did not work when I opened the doors. All of this with the truck running with remote start. Once I pressed the start button, Everything worked as it should.

I remote start every morning for a few min to get some oil moving and heat in the engine before driving off. Never had any of this happen before.

maybe you got some kind of update last night.

 

[scott011422]

not that i was made aware of? Does Fordpass always notify you?

 

[Graygoose2021]

It may show latest update and date.

I finally went and bought a 3 year warranty Duralast and installed it Friday. Was nervous with all the warning signs.

 

[Gros Ventre]

Beginning to wonder if the Ford OEM battey is the problem. Thanksgiving weekend a year ago I had some battery alerts. Since it was Thanksgiving weekend with much travel for family get togethers, I located a NAPA store along my route and bought a replacement AGM battery. Finished travels and on return home did the low rate "wetting down" charge I've spoken of. Have had zero peeps out of the electrical system since. Had that OEM battery checked out by my dealer and it was reported OK. Still, am curious if those who've had these issues have replaced their battery and whether a new, non-OEM battery made a difference.

 

[SemperVee]

One thing I learned is when charging>> Of extreme importance is NOT to put the Negative connection directly on the battery post. YOU MUST bypass the BMS plug and connect on the other side of the plug for the vehicle to see that charge. Ford does not let it charge more than 60-70% Frustrating from how I understood it all my life.

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