Charging rates

[Spiffy]

What is the voltage that my truck is supposed to charge at?
I'm suspicious that my truck is charging too high.

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[Gros Ventre]

It depends partly on temperature. You'll see, in my observation, about 15.1 VDC. The summertime float voltage is around 12.8-12.9VDC. Unless you're in deep winter in Wyoming or Montana... you ought to see system voltage drop to 13 or 14 VDC. You can lookup the temperature curves for charging and floating.

 

[Buyer2021]

What is the voltage that my truck is supposed to charge at?
I'm suspicious that my truck is charging too high.

See the attachment 414-00 CHARGING SYSTEM OPERATION at this post for an explanation of the various condition-based charging rates.

The extremes of the range are 12.2V to 15.2V depending on a variety of factors. The typical maximum rate is 14.5~14.9V.

 

[Spiffy]

It depends partly on temperature. You'll see, in my observation, about 15.1 VDC. The summertime float voltage is around 12.8-12.9VDC. Unless you're in deep winter in Wyoming or Montana... you ought to see system voltage drop to 13 or 14 VDC. You can lookup the temperature curves for charging and floating.

Hmm. I have two batteries fail this week. A agm h7 optima and a dealer replaced h7.
Their float voltage drops to around 11.7 5 min after shutting off truck. I returned the optima and installed the new dealer h7 and within 3 days the new dealer battery failed.

I have a brand new sams club Duracell agm h7 sitting on smart charger that I'm afraid of installing. Please look at the how the battery reacts. See how fast it drops from 15+ volts to under 12v.

 

[Spiffy]

Each peak is when the truck is running. It's charging as you confirmed.

 

[Buyer2021]

Their float voltage drops to around 11.7 5 min after shutting off truck

Note that there are likely meaningful system loads on the battery continuing more than 5-minutes after key/engine off.

 

[Gros Ventre]

When you shutdown the engine the system voltage should drop to battery no load voltage immediately. As I understand it, Ford has programmed the charging rate to place the battery at 80% charge or about 12.8-12.9 VDC. If there are loads remaining on, and there are some, the battery voltage will be below the above voltages. There's another post that includes some info pages. One item is that it states there are several 10mA loads that remain on after shutting down the engine. So your battery will slowly drain when off. I do not like the graph above. It speaks to a progressive lowering of engine off voltages.

 

[Gros Ventre]

Go to this post and scroll down to the attachments.
https://www.f150gen14.com/forum/threads/agm-vs-wet.31584/#post-563944

 

[Spiffy]

I do not like the graph above. It speaks to a progressive lowering of engine off voltages.

I'm not sure i understand what you mean.

 

[Gros Ventre]

I'm not sure i understand what you mean.

The engine off voltages are dropping day by day, even though there are engine on runs nearly every day. I'd expect the engine off voltages to come back to the same starting point after each engine run time. They don't, instead they drop each time. Just realized you have a PB. The traction battery comes on line during engine start and also sustains the system voltage. Both the alternator and the traction motor/generator can charge the battery as commanded by the system. What I don't like is the progressive lowering of engine off voltages. Are your engine on/runs very short or are some of them and hour or more? A bunch of short runs can give you a progressive lowering of battery voltage by not allowing a full recharge. Remember that charging can be very slow for the last little bits.

 

[Spiffy]

Yes that's what I'm seeing.
1 month ago my original battery soc started to go into sleep mode. Lots of electrical gremlins.
10 days ago I got the dealer to replace the battery with a h7. Two hours later I removed it to use in another truck and installed a new optima h7 agm. It lasted 3 days. Store tested it as bad. Returned.
I reinstalled the new dealer supplied h7 agm. It started to go into sleep mode. I installed the Bluetooth monitor as seen in that chart. I used dealer quality tester on the battery and it shows the new battery defective also even though it's a H7.

I have a brand new Duracell h7 sitting on a charger. I'm afraid to install it.

 

[Spiffy]

I did read the attachments. Now I have the info I need to determine if I have a charging errors, high parasitic draw or just bad luck with Ford batteries

 

[powerboatr]

As a non pb owner
The one thing that I dont fully understand
Is the hvb is the alternator for the vehicle.. if hvb is charged.. why does it not keep the little 12v battery topped off all tye time?
My parent have a hybrid maverick
It killed the 12 volt battery because of short trips etc, similar to this thread

Imo. Poweboost should very very rarely have 12volt battery issue unless hvb is depleted?

 

[Buyer2021]

if I have a charging errors

Highly unlikely, IMO. Methinks most likely your charging system is responding as intended to the conditions it senses.

More likely is that you have a combination of battery condition, charging cycles (e.g. the previously mentioned drive-duration / frequency), and / or loads ('normal' or 'abnormal' parasitic) that are causing the effects you observe.

Perhaps related .... there has been an OTA update which tweaked the power management system in some manner to improve battery maintenance. See update version 10.1.1 / Sept 2024 on the F150 spreadsheet at this post. You might want to investigate whether or not you have received that update. @rugedraw can probably help with that determination if you DM you VIN to him (do not post your VIN in a public thread asking for that help! ).

 

[SumGuy]

So what I am reading here is that Ford has designed the charging system to require long trips for whatever reason. Is this because Ford uses a substandard alternator?

for example, my wife’s older Audi q5 rarely drives more than 15 mins at a time. Work, trips to stores in our area, et al. Maybe once a week an hour-ish drive somewhere, but always in city traffic. Never had a single battery issue in 5 years.

my truck has mostly similar driving patterns - with a weekend warrior drive to somewhere for an few hours most weekends.

my truck constantly falls into deep sleep mode. No exterior approach lights, no interior lights, et al. Why?

my guess is some value engineering where they could down rate the alternator and save $0.10 in copper per truck, but at the expense of all of these issues.

I would love to hear it isn’t something like this.

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