HYBRID 12V Battery Mystery SOLVED

[Mavster Mechanic]

That’s good and bad, the good is that it’s charging the battery, the bad is that it’s charging the battery and never stops even when the battery is fully charged , and now it’s over charging the battery.

It does not overcharge.
It stops charging at 100%.

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[Mavster Mechanic]

All I am saying is that the batteries are not wearing out early on the cars that don't have the battery drain. I know what your theory says. And I understand. But I'm telling you what is not happening on the ground. Every battery that is failing prematurely also has a drain. On everyone where the drain is fixed the battery lasts. Most of The Mavericks that don't have the battery drain issue are still on their original battery. And the ones who don't have the drain have a battery failure rate about the same as the rest of the vehicles. And my bosses are not telling me to peddle anything. I'm speaking on my observations.

You are a kind an helpful person.
This is not as simple as you make it out to be. And perhaps there are multiple issues simultaneously.

I'm telling you I have a 2022.
Battery had low voltage from day one.
Battery hovered around 60% charged for 3.5 years. Never going dead, but by happenstance, only charging fully on all day drives with a trailer.

Started every day. But had very little reserve. Running the radio and nothing else for 30 minutes to an hour would kick off battery saver, no dome light, etc.

I put a shunt and data logger on the battery.
No parasitic draw. I didn't have that problem.

I had and may still have a badly done BMS.

You have never explained, what is the point of PURPOSEFULLY draining a lead-acid battery to 60%, or 80% and holding it there? Because trucks are doing that. And I have never read any data this is a desirable trait. Can you explain this behavior?

 

[inline_five]

The latest SSM for the battery drain issue is 54785. The SSM number may change if they add another detail. But as of today that's the latest. Also DEFINITELY tell them to do a battery test , a full recharge (if a New battery is not been recently installed and then doing a BMS reset. You should then be good to go on this problem. But to get it done simply tell them that sometimes your battery drains after sitting. Also tell them to perform SSM 52307 for an inaccurate deep sleep notification in your Ford pass app

Awesome thank you for the help/information!!

 

[inline_five]

Pre-25MY have no set Ah rating, Relearn trying to figure it out - perhaps close enough?

https://www.batteryuniversity.com/article/bu-403-charging-lead-acid

The battery is fully charged when the current drops to a set low level. The float voltage is reduced. Float charge compensates for self-discharge that all batteries exhibit.

The switch from Stage 1 to 2 occurs seamlessly and happens when the battery reaches the set voltage limit. The current begins to drop as the battery starts to saturate; full charge is reached when the current decreases to 3–5 percent of the Ah rating. A battery with high leakage may never attain this low saturation current, and a plateau timer takes over to end the charge.

The correct setting of the charge voltage limit is critical and ranges from 2.30V to 2.45V per cell. Setting the voltage threshold is a compromise and battery experts refer to this as “dancing on the head of a pin.” On one hand, the battery wants to be fully charged to get maximum capacity and avoid sulfation on the negative plate; on the other hand, over-saturation by not switching to float charge causes grid corrosion on the positive plate. This also leads to gassing and water-loss.

Temperature changes the voltage and this makes “dancing on the head of a pin” more difficult. A warmer ambient requires a slightly lower voltage threshold and a colder temperature prefers a higher setting. Chargers exposed to temperature fluctuations include temperature sensors to adjust the charge voltage for optimum charge efficiency. (See BU-410: Charging at High and Low Temperatures )

Once fully charged through saturation, the battery should not dwell at the topping voltage for more than 48 hours and must be reduced to the float voltage level. This is especially critical for sealed systems because they are less tolerant to overcharge than the flooded type. Charging beyond the specified limits turns redundant energy into heat and the battery begins to gas.

The recommended float voltage of most flooded lead acid batteries is 2.25V to 2.27V/cell. Large stationary batteries at 25°C (77°F) typically float at 2.25V/cell. Manufacturers recommend lowering the float charge when the ambient temperature rises above 29°C (85°F).

Not all chargers feature float charge and very few road vehicles have this provision. If your charger stays on topping charge and does not drop below 2.30V/cell, remove the charge after 48 hours of charging. Recharge every 6 months while in storage; AGM every 6–12 months.

Aging batteries pose a challenge when setting the float charge voltage because each cell has its own unique condition. Connected in a string, all cells receive the same charge current and controlling individual cell voltages as each reaches full capacity is almost impossible. Weak cells may go into overcharge while strong cells remain in a starved state. A float current that is too high for the faded cell might sulfate the strong neighbor due to undercharge. Cell-balancing devices are available compensate for the differences in voltages caused by cell imbalance.

This is all good information. Yet my 1995 Volvo with a six year old Walmart $80 lead acid battery still cranks every time and cranks well. I drive it once a week, approximately 25 minutes, to and from the airport where it sits for 3-4 days and then I drive it back.

Notably, I keep a cheap 20w solar panel battery charger on it when parked.

I will say that battery when driven is around 13.0v and when shut off, the panel puts about 14v into it at peak sun. There is no smart BMS or charger helping it stay perfectly charged.

Another interesting tidbit, my wife's 2010 Prius with a 10 year old generic AGM still cranks and runs fine, zero issues whatsoever in those 10 years, and sits for days at a time with no charger on it. It's driven a few times a week (at most) on short 10-15 min drives running errands. Voltage at rest is approximately 12.2v.

Correct me if I'm wrong,

With a constant voltage (say 13.5, 14.0, 14.5 your pick) no "brains" are necessary.

The battery will take what it needs, reach homeostasis, and current will stop flowing into it.

I don't understand the need for all the voodoo witchcraft here.

Yes this is correct. I have a simple DC desktop battery supply I use to charge my 18650 Li-ion batteries. I select 3.9v and 1 amp, and it supplies 3.9v @ 1 amp until getting close to 3.9v, where the amperage slowly drops down. When amps hit around 0.10 remove the battery. But eventually amps would go to 0.0 on their own, there is no brain needed. This is probably why car alternators were set at ~14.0v initially and will float down to ~13v once the battery stops taking amps.

 

[Red Eyes - Wide Shut]

I just replaced the battery in My daughter's 2017 Volt with only 56k miles a couple weeks ago. Battery was at 31% and still started the car. We knew it was the battery after it started throwing off random codes along with a code about low voltage code. Never charged the battery and it sat at times as evidence by the mileage. 9 years from a hybrid.
Thanks to having to deal with my issue, reading and learning about parasitic draws lack of charging on and on, has made me more informed about all this watcha ma call its software computer driven stuff.
Thanks to all those with smart and helpful knowledge. More than I should really need to know.
I remember when there was a time I could pull motors, rebuild a whole car. Now you need a laptop and a robot, a nox sensor and a lot of money to just maintain them.

 

[Master Blaster]

It does not overcharge.
It stops charging at 100%.

Ford has funny ideas about what a fully charged battery is. They mark 80% as 100%, and it never gets anywhere near 100% ever. That's why EFL batteries are only lasting 1 year and AGM only 2 years instead of the expected 5 to 8 years.

If you don't believe it, disconnect the battery after a long drive with the lights on and measure the battery with a known-good meter after the normal 12hr soak. Its not 13.2V or 13.4V like it should be, its only 12.1V to 12.4V.

 

[Mavster Mechanic]

Ford has funny ideas about what a fully charged battery is. They mark 80% as 100%, and it never gets anywhere near 100% ever. That's why EFL batteries are only lasting 1 year and AGM only 2 years instead of the expected 5 to 8 years.

If you don't believe it, disconnect the battery after a long drive with the lights on and measure the battery with a known-good meter after the normal 12hr soak. Its not 13.2V or 13.4V like it should be, its only 12.1V to 12.4V.

Mine, and presumably everyone's trucks will charge the 12v battery to 100% if you just have the discipline to run your headlamps or parking lamps all the time. If you want to be lazy, you can use Forscan to program the truck to do this for you.

Call it a work-around that works.

If your voltage is low, your battery is already damaged perhaps beyond repair.

 

[MakinDoForNow]

Ford has funny ideas about what a fully charged battery is. They mark 80% as 100%, and it never gets anywhere near 100% ever. That's why EFL batteries are only lasting 1 year and AGM only 2 years instead of the expected 5 to 8 years.

If you don't believe it, disconnect the battery after a long drive with the lights on and measure the battery with a known-good meter after the normal 12hr soak. Its not 13.2V or 13.4V like it should be, its only 12.1V to 12.4V.

To keep anything from affecting the battery reading after the soak either leave the hood up during the 12hr soak (preferred) or raise the hood 90 minutes for things to go quiet after opening door and raising hood. Then in EB you can use the battery posts OR with Hybrid TAKE READINGS USING THE JUMP PINS!!!". Only way I have found on hybrid to get 12.9v after rest on 3.8 year old OEM 390 CCA 12V. Do not approach the truck with a fob moving as that might be detected.

 

[HeyBales]

Ford has funny ideas about what a fully charged battery is. They mark 80% as 100%, and it never gets anywhere near 100% ever. That's why EFL batteries are only lasting 1 year and AGM only 2 years instead of the expected 5 to 8 years.

If you don't believe it, disconnect the battery after a long drive with the lights on and measure the battery with a known-good meter after the normal 12hr soak. Its not 13.2V or 13.4V like it should be, its only 12.1V to 12.4V.

85% on SLA batteries.
Seems 92% on AGM.
With no programming change required!

80% on SLA is when the float charge starts, close to 1/2 Amp.
87% on AGM I recall it being noted.

Of course - once it's lost it - throw that 80/87% out the window - the goal has changed.
Never mind full change, whatever it takes to keep it at a happy 11.8 V it seems for me!

This was 51% SOC after having 54% last night on park.
300 day battery. And it reached this low actually logging it thinks almost equal charging to discharge Ah's seen. Which I guess makes sense, if a fully charged battery sat for 300 days no connections - it might drop to 11.8 V. (come on BMS - do some Management and charge more for the self-discharge that occurs)

 

[Red Eyes - Wide Shut]

To keep anything from affecting the battery reading after the soak either leave the hood up during the 12hr soak (preferred) or raise the hood 90 minutes for things to go quiet after opening door and raising hood. Then in EB you can use the battery posts OR with Hybrid TAKE READINGS USING THE JUMP PINS!!!". Only way I have found on hybrid to get 12.9v after rest on 3.8 year old OEM 390 CCA 12V. Do not approach the truck with a fob moving as that might be detected.

Is that really a real thing. I've heard so many different methods in this forum other than fixing it.

I left the key on all night and let the air out of the tires. Then while walking to work in the morning, I kicked a can down the road to symbolize how the Blue OutofRound has dealt with this.

 

[johnDeere]

To keep anything from affecting the battery reading after the soak either leave the hood up during the 12hr soak (preferred) or raise the hood 90 minutes for things to go quiet after opening door and raising hood. Then in EB you can use the battery posts OR with Hybrid TAKE READINGS USING THE JUMP PINS!!!". Only way I have found on hybrid to get 12.9v after rest on 3.8 year old OEM 390 CCA 12V. Do not approach the truck with a fob moving as that might be detected.

That looks like way too much work, I have a easier way.
I just look through the window.
And by the way, the WonVon unit is powered from a separate battery.

 

[SafetyGuy]

That looks like way too much work, I have a easier way.
I just look through the window.
And by the way, the WonVon unit is powered from a separate battery.

Good day

Nice indicator, and it shows amps as well! I have been looking for one like that but no luck so far.

Just a note, when you can see the voltage after the truck is shut off, you aren't getting a true reading as to the battery actual charge level.

It is showing the voltage with a small load applied.

To get the true voltage reading on the battery you need to wait for the 90 minutes to pass, and all power demands are removed...and then wait a bit more for the battery to "relax".

I do the same thing as you of course (my indicator sucks...it only shows me voltage ;-), I just peek through the side window to see what the voltage reading is.

Of course, the most accurate place to read the battery is right at the battery, but if you can compare the 2 readings (boost points under the hood vs the battery itself) and remember the difference you are golden!

All this is work of course, and if you aren't having any 12 volt battery or charge issues, why would you do all this, eh?

Have a good one,

Andy

 

[El Kabong]

That looks like way too much work, I have a easier way.
I just look through the window.
And by the way, the WonVon unit is powered from a separate battery.

Would love to see details on how that was installed - it comes with it's own shut. How do you keep it's (auxiliary) battery charged? Where in the truck did you mount the display?

 

[johnDeere]

Would love to see details on how that was installed - it comes with it's own shut. How do you keep it's (auxiliary) battery charged? Where in the truck did you mount the display?

There is another battery under the seat, and a smart battery charger plugged into the 115v outlet.
The display is in front of the shifting knob.

 

[El Kabong]

There is another battery under the seat, and a smart battery charger plugged into the 115v outlet.
The display is in front of the shifting knob.

What about the shunt? Is it between the BMS sensor and ground or connected to ground after the BMS sensor?

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