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Battery Charging Observations

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Spidergears

Spidergears

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An exponential decline in charging current is how batteries work. I have begun to wonder about Ford's programming. Some detailed homework surfaced that 12.69VDC is the theoretical fully charged voltage. As it appears to me Ford has programmed 12.7VDC as the 80% charged point. Well, why would they do this? I believe that Ford has assessed th lifetime of AGM batteries and concluded that going above that 12.7VDC point will, in the long term, overcharge the batteries. My homework also revealed that AGM batteries are more susceptible to damage from overcharging than a typical flooded cell battery. I have begun taking a voltage reading, with a handheld Digital Voltmeter, every morning. I leave the hood unlatched so that I don't have to trigger modules. I find that the battery, after sitting overnight will have a rest voltage of around 12.8VDC. It then declines about 0.05VDC day by day. recall that lead acid batteries will have a self-discharge rate of about 1% or 2% per week. You can't change this, it's a fact of how these batteries work. So what's up? Well first I finally figured out that the truck is "Always on." It has to be so that when you approach it with your key FOB, it'll recognize it and unlock the doors. So, engine on or engine off, the computer is active. Admittedly, its active at a very low current draw, but it's there. Combine that with a self discharge rate and no matter what you'll see battery voltage slowly declining... Now do you have some modules that aren't turning off when they should have been commanded? Go take a look.
I get the decline in charging, I just didn’t expect it to be so low for my given state of charge.

As far as modules go, nothing obvious is on. Any suggestions on how to do a deeper diagnosis of this? Ive recently started leaving my obdlink mx plugged in, but it shuts off pretty quickly after the key is off, likely due to the truck cutting power to the port.
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Spidergears

Spidergears

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A huge swath of the country just saw temperatures that they've never seen before or haven't seen for more than a year. It's not unreasonable to expect a lot of people to report problems during and shortly after the first big temperature drop. I highly doubt it has anything to do with what Ford is doing with updates.
except the deep sleep isn’t a recent issue for a lot of folks, I’m in the south, and I’ve been having the issue for a few months even when it was warm.

At least with the logging of my truck, the rate of charge is incredibly low when running for the soc. did that start with an update? Not sure…but seems possible.
 

Gros Ventre

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I get the decline in charging, I just didn’t expect it to be so low for my given state of charge.

As far as modules go, nothing obvious is on. Any suggestions on how to do a deeper diagnosis of this? Ive recently started leaving my obdlink mx plugged in, but it shuts off pretty quickly after the key is off, likely due to the truck cutting power to the port.
I'm only now learning my way around all of this software... Snakebitten would be a good guy to look to on the module issue. My old fashioned way of doing that would be to start selectively pulling fuses until I found a circuit that when deenergized didn't drop the voltage. My take on things is that an adequately charged battery will be around 12.8 VDC (engine off-key off) given that you didn't trigger anything when taking the reading. Then expect a slow decline day by day of maybe 0.05 VDC. The normal minimum voltage on starting in those olden days was 10.5VDC but with the DC-DC converter from the Hybrid battery that's going to be different... what baffles me is I don't see any of this drain going on in my truck. But then I saw some odd readings early on and jsut did a replacement. It's as if some software has errors in it and others don't. Why can't Ford come up with a diagnostic set of software... I still think the first step would be to replace the OEM Ford battery with a non-Ford battery.
 

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I'm only now learning my way around all of this software... Snakebitten would be a good guy to look to on the module issue. My old fashioned way of doing that would be to start selectively pulling fuses until I found a circuit that when deenergized didn't drop the voltage. My take on things is that an adequately charged battery will be around 12.8 VDC (engine off-key off) given that you didn't trigger anything when taking the reading. Then expect a slow decline day by day of maybe 0.05 VDC. The normal minimum voltage on starting in those olden days was 10.5VDC but with the DC-DC converter from the Hybrid battery that's going to be different... what baffles me is I don't see any of this drain going on in my truck. But then I saw some odd readings early on and jsut did a replacement. It's as if some software has errors in it and others don't. Why can't Ford come up with a diagnostic set of software... I still think the first step would be to replace the OEM Ford battery with a non-Ford battery.
Your "old fashioned" way of isolating a parasitic draw is the only way I know of doing the same.
But first I would want evidence that I even have a suspect parasitic draw.

Keep in mind that to some extent even the most healthy Gen14 truck has a parasitic draw by design. But it's supposed to be less than .5 amps after 75 minutes of shutdown. (turning the truck off)

For myself, I use the Bluetooth voltage meter and look at the 24hr logs to see evidence of an unusual tax on the AGM. Unless there is evidence that the voltage is dropping significantly while the truck is "off", I wouldn't waste my time chasing the rabbit.

Of course it would be awesome if the OBD port could be powered independently of waking up the truck, because THAT would allow you to probe various modules using smartphone apps and literally monitor the current being drawn from the 12V system. However, that's a parasitic draw itself. Lol

I'll tell you the most bizarre thing I see on a few occasions with my Powerboost is discovering the High Voltage battery SOC dropped while the truck was off. That's a heck of a lot more missing electrons than a 12V AGM losing .5 Volts mysteriously!

I've made a habit of not shutting the truck down until the High Voltage battery is at 63% SOC. 98% of the time when I next wake the truck up the High Voltage battery is right where it left off. ~63% SOC.
But I have on a few occasions started the truck and ICE immediately fired up and only to find the High Voltage SOC in the 3X% range. WTH could possibly be awake in the shutdown truck to tax the High Voltage battery? And that much?
After all, it takes 20 minutes to draw the High Voltage battery down from 63% to 42% with the truck ON and HVAC running, along with Sync4 playing tunes, and onboard Wifi providing bandwidth for my laptop and me taking business calls on Bluetooth.

I might never know, but I am SO curious and have pondered many times how I might build a trap to at least see the footprint left that confirms the DC/DC converter was functioning with the truck off. Surely the OBD interface is alive in such an event?

One thing that I think is fair to assume is that the OTA capability of the vehicle, by its very nature, opens the possibility for any/all modules to be remotely awakened and thus consume electrons from the 3 storage devices the truck contains. (12V AGM/12V auxiliary/385V HV battery)
 

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Your "old fashioned" way of isolating a parasitic draw is the only way I know of doing the same.
But first I would want evidence that I even have a suspect parasitic draw.

Keep in mind that to some extent even the most healthy Gen14 truck has a parasitic draw by design. But it's supposed to be less than .5 amps after 75 minutes of shutdown. (turning the truck off)

For myself, I use the Bluetooth voltage meter and look at the 24hr logs to see evidence of an unusual tax on the AGM. Unless there is evidence that the voltage is dropping significantly while the truck is "off", I wouldn't waste my time chasing the rabbit.

Of course it would be awesome if the OBD port could be powered independently of waking up the truck, because THAT would allow you to probe various modules using smartphone apps and literally monitor the current being drawn from the 12V system. However, that's a parasitic draw itself. Lol

I'll tell you the most bizarre thing I see on a few occasions with my Powerboost is discovering the High Voltage battery SOC dropped while the truck was off. That's a heck of a lot more missing electrons than a 12V AGM losing .5 Volts mysteriously!

I've made a habit of not shutting the truck down until the High Voltage battery is at 63% SOC. 98% of the time when I next wake the truck up the High Voltage battery is right where it left off. ~63% SOC.
But I have on a few occasions started the truck and ICE immediately fired up and only to find the High Voltage SOC in the 3X% range. WTH could possibly be awake in the shutdown truck to tax the High Voltage battery? And that much?
After all, it takes 20 minutes to draw the High Voltage battery down from 63% to 42% with the truck ON and HVAC running, along with Sync4 playing tunes, and onboard Wifi providing bandwidth for my laptop and me taking business calls on Bluetooth.

I might never know, but I am SO curious and have pondered many times how I might build a trap to at least see the footprint left that confirms the DC/DC converter was functioning with the truck off. Surely the OBD interface is alive in such an event?

One thing that I think is fair to assume is that the OTA capability of the vehicle, by its very nature, opens the possibility for any/all modules to be remotely awakened and thus consume electrons from the 3 storage devices the truck contains. (12V AGM/12V auxiliary/385V HV battery)
I think the big thing is that the truck is never "off." It may be Engine Off-Key off but there is by design a slight draw on the battery. Note that half an amp (0.5a) is a big drain. It amounts to 12 Amp-Hours in a 24 hour day. I suspect Ford did not intend that large a drain on the battery. Anything larger than, say 50 mA, is a parasitic drain.
I'm wondering if those occurrences where you found the SOC of the Hybrid battery low after sitting was caused by it being triggered to feed the 12VDC system until it itself reached its low limit.
I base my thinking on reading the 12VDC system voltage with a handheld voltmeter, at the battery posts. Once again, I do not trust the computer to tell me anything except what its programmer wants me to know. In taking daily readings I see a slight drop in rest voltage of 0.03 to 0.05 VDC. I view that as consistent with a slight drain running the central computer and some sensors combined with normal self discharge.
 

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I put a battery monitor on my powerboost yesterday and this morning on the way to work it was reading 15.15 volts charging throughout my 10 min/3 mile drive. In fact I watched it drop down to 13.2 ish momentarily around 4 times but would jump right back up after a few seconds. Yesterday I took two short trips, one showed 14.7 charging and the other 14.65. I think my battery has been hovering around 12.59 resting volts. I have read that anything over 14.75 volts could be considered over charging.

Has anyone else seen charging at 15v+?

Ford F-150 Battery Charging Observations Screenshot 2024-01-24 at 7.48.38 AM
 
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Heh. ChrisFix has a way to help detect parasitic draw. Anybody have a flir?


 

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I have not made sense of the Ford charging strategy as reflected in system voltage. What one might expect to see is a voltage of around 14.5VDC to 15.0VDC or so. right after start. What I commonly see is 15.1 VDC or 15.2VDC and it stays high for sometimes hours after start even with extended highway travel. Then magically it'll drop to 14.1VDC and then to 12.9VDC... The common pattern I expect to see is the higher recharging voltage declining exponentially to around 13.2VDC based on flooded cell observations. I've observed a Jeep winching opertion where current draw pulled system voltage down to 9 or 10 VDC, having maxed out the alternator production, the engine kept running and when the operation was over the battery recharged over about an hour right up to 13.2VDC. But this Ford strategy just seems to hop around. I suppose the gas recombination feature of AGM batteries allows that, but even then overcharging will produce gases inside the active material and cause a spalling off of active material shortening the battery life... I just don't see the logic of Ford's programming.
 

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To answer Loudog, I frequently see charging at over 15V with my bluetooth voltmeter.
 

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I see 15.1 or 15.2VDC all the time. It seems to stay around that value for far longer than I think the battery needs to be properly and fully charged. As I remarked above, I cannot figure out Ford's programming logic.
 
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Saw 15+ often with old battery I replaced that was giving me low battery warnings. Trying to force battery to charge I guess. 🤷‍♂️
Rarely see it with new battery but it is only a month old.
 

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Picked up my truck from the dealer and this morning and when I was leaving from work the engine kicked on right away. Decided to open up OBDLink and check the 12V SOC. It was at 62% when I got the app open and was up to 67% when I got home. The voltage was at 14.9V and the DC/DC transformer had 40A+ on the low voltage side the entire drive. Going to watch it the rest of the week now. In the past I was typically around 75% on my original battery.
 

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What does vehicle battery current mean with the Obdlink? Mine is almost always at 2.0 Amp. Is it what the alternator is charging the battery at?
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