Bad 12V battery after 3 years

[wolfman1]

So got the BT monitor installed, so just a little data from today. I did use forscan and update the charge% to 90% from 80% at lunch, so not much drive time for that to make any difference, but certainly not seeing the 13.xv you guys are seeing. But given the typical AGM voltage chart, where 12.5 to 12.75 is 80% to 90%, why would it normally get charged to 13.x by the computer/bcm/inverter if its only set to 80%?

Anyway easy to keep an eye on it now and obviously 12.71 isnt low, but open to anyone's thoughts!

I'm struggling to find the FORScan section that notes how to adjust the battery charge %. Can you let me know where to find that?

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[wolfman1]

Since nobody else is jumping on, I see a lot of references to OBDLink (MX+ or LX). @Snakebitten should get a commission, since his posts compelled me to drop $$$ on the MX+ a few minutes ago.

My battery was so low this morning that the truck wouldn't even deploy the running boards. It seems like a good time to upgrade from my 20 year old OBD scanner and get some fancy metrics. The embarrassingly bad design of the charging system tempers my usual joy of getting a new toy tool.

This is what I use based on a @Snakebitten reco in a different thread: https://a.co/d/bSfPulH

 

[Snakebitten]

For clarification.....

The OBDlink adapter (MX) is for monitoring PIDs onboard the vehicle while it is energized. While it is "On"

The Bluetooth voltometer is for logging the AGM/low voltage voltage in real-time, as well as 24/7/365

It takes both tools to collect and/or monitor exactly what is going on with the charging system of the truck, as well as the results of that charging strategy.

If your truck isn't exhibiting any strange behavior, like going into deep sleep, or disabling interior lighting, or refusing to deploy the running boards, or.........you get the idea.......well you don't need these tools. But if you do find yourself battling low voltage symptoms, combined the tools can help you confirm the low voltage issue, and even assist in knowing if/when you need to charge or replace the battery. Or batteries, in the case of the Powerboost.

 

[CoolDuDe919]

I'm struggling to find the FORScan section that notes how to adjust the battery charge %. Can you let me know where to find that?

You can go under BdyCM config, the "simple", so non as built, works fine and shows battery charge percent.

Quick update, i threw mine on the charger yesterday, then this morning i up'd the forscan charge % to 100%. There was some forum chatter about someone putting their's over 100%, 110% or 120% or something like that, which i found interesting.

Wasnt super fond of where the BCM was maintaining it after a few days it was ~12.5x v.

It stabilized at 13.11 v or so yesterday, so that seems to be its somewhat normalized resting volt off the charger.

Will continue to monitor and see where it goes. I dont seem to have a large overnight/resting drop, very small/gradual over time, so i dont think i have a parasitic draw issue.

 

[Hans Moleman]

Yes the charging is terrible even after the updates. Every couple of weeks it will drop to 80% SoC because the charging is not keeping up so I have to put it on the charger to get it back to 95% SoC.

 

[ScottyT]

What is involved in switching to the LFP for your aux battery?

 

[CoolDuDe919]

Ok some data for those interested. Had work trip so the truck sat for several days. Few notes

1. Truck started at 12.81v after a 2 hour drive
2. Put something in the truck at ~3:30am, so running boards out/in once plus fullwake up+ locking and walking away
3. This single event lost around .07v
4. Sitting for basically a bit less than 72 hours, went from 12.81 to 12.56, or you could almost add on .07v, so 12.63v, if i hadnt gotten into the truck.
5. Given i was at 12.81v after a 2h hour drive, on blower setting 5, after setting forscan to 100%, my BMS didnt seem to want to take it any higher.
6. After the 2 hour drive home, i was at 12.73v.
7. Last few days of shorter drives around town, i end up at ~12.56v or so
8. You can see even after my time on the charger back on the 2nd. the BMS continued to bring it down further to where i sit now, up to 12.7xv to 12.8xv on longer trips, and 12.5x on shorter trips.

Anyway, thought i was interesting, im still between 80%-90% on the AGM voltage chart so no worries or concerns, but our buddy @Snakebitten may be an outlier hanging out at 13.xv.

 

[HammaMan]

13v is easy to stay above

 

[Snakebitten]

Ok some data for those interested. Had work trip so the truck sat for several days. Few notes

1. Truck started at 12.81v after a 2 hour drive
2. Put something in the truck at ~3:30am, so running boards out/in once plus fullwake up+ locking and walking away
3. This single event lost around .07v
4. Sitting for basically a bit less than 72 hours, went from 12.81 to 12.56, or you could almost add on .07v, so 12.63v, if i hadnt gotten into the truck.
5. Given i was at 12.81v after a 2h hour drive, on blower setting 5, after setting forscan to 100%, my BMS didnt seem to want to take it any higher.
6. After the 2 hour drive home, i was at 12.73v.
7. Last few days of shorter drives around town, i end up at ~12.56v or so
8. You can see even after my time on the charger back on the 2nd. the BMS continued to bring it down further to where i sit now, up to 12.7xv to 12.8xv on longer trips, and 12.5x on shorter trips.

Anyway, thought i was interesting, im still between 80%-90% on the AGM voltage chart so no worries or concerns, but our buddy @Snakebitten may be an outlier hanging out at 13.xv.

If you are staying above 12.5 after parked for a few days and a disturbance or 2, you are doing pretty good in my opinion. I don't think you'll be dealing with the BMS "protection" stepping in anyways.

As for the 13.X Volts my truck sits at, it's not a fair comparison. I AM an outlier, but not alone. HammaMan and myself, along with a few others, have an LFP Auxiliary battery under the back seat, in place of the factory AGM. The nature of the LFP, combined with the underhood AGM, raises the resting voltage of the truck a little higher than a fully charged brand new AGM is capable of.

 

[CoolDuDe919]

If you are staying above 12.5 after parked for a few days and a disturbance or 2, you are doing pretty good in my opinion. I don't think you'll be dealing with the BMS "protection" stepping in anyways.

As for the 13.X Volts my truck sits at, it's not a fair comparison. I AM an outlier, but not alone. HammaMan and myself, along with a few others, have an LFP Auxiliary battery under the back seat, in place of the factory AGM. The nature of the LFP, combined with the underhood AGM, raises the resting voltage of the truck a little higher than a fully charged brand new AGM is capable of.

I have an LFP too. However, thinking about it, im betting tempature is playing a factor here. Im in missouri, temps have been 30's to 40's the past few weeks. I see your in coastal texas. Id imagine if my temps were in the 70's or 80's, id be seeing a bit higher voltage as well.

 

[Snakebitten]

I have an LFP too. However, thinking about it, im betting tempature is playing a factor here. Im in missouri, temps have been 30's to 40's the past few weeks. I see your in coastal texas. Id imagine if my temps were in the 70's or 80's, id be seeing a bit higher voltage as well.

Oops.
I can't keep up with all the fellas that have jumped in on the LFP experiment.

Did you go through the effort to balance the LFP before installing?

 

[ScottyT]

Will going with LFP on aux battery void extended warranties? And I am still hoping somone here explains how to switch to LFP.

 

[HammaMan]

I have an LFP too. However, thinking about it, im betting tempature is playing a factor here. Im in missouri, temps have been 30's to 40's the past few weeks. I see your in coastal texas. Id imagine if my temps were in the 70's or 80's, id be seeing a bit higher voltage as well.

Your batt may have low temp charging protection in it. Typically if temps dip below freezing, the BMS won't turn the charging capabilities back on until 41 degrees.

 

[CoolDuDe919]

OK so i made the 2 changes recently Hyins as suggested. and i continue to see a voltage bump up after each drive. Set charge% to 120% and set Ford Smart Regenerative Charging to disabled.

https://www.f150gen14.com/forum/thr...ge-how-to-power-accessories.13862/post-452723

I was hanging around 12.5x a lot, after this today alone ive gone up to 12.6x, 12.7x, ending at 12.75v.

Anyway thought you guys would find this interesting, i will continue to monitor and see where my new peak ends up at, and if needed i can dial it back some.

 

[tsigwing]

Nope.
Keeping the AGM battery under the hood. But I did install a small LFP 25AH Auxiliary battery in place of the little 7AH AGM.

Really curious how much positive influence it will have at "propping up" the AGM.

I "balanced" the LFP before installing it. (Thanks @HammaMan for your guidance. It took 3 nights of 25 milliamps charging to get the cheap Chinese BMS to balance the 4 3.65V cells. But I finally achieved a 14.57V charge.)

After installing the LFP Auxiliary, a couple of hours later the truck is sitting at a nice resting voltage. ?

Underhood AGM is on day 980
I did not reset the truck's BMS

Not sure if I missed it or not, but care to share which battery you got?

https://www.amazon.com/gp/product/B09NB97XGL/ref=sw_img_1?smid=A5KU5HDAPDC75&th=1

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