Update on my replacement lead-acid battery in my 24 hybrid

[Raymundo76]

As stated in a prior post, Ford replaced with the same type (warranty and not AGM); it appears to be marginally better. Had not driven the Mav for 2 days. Before replacement the voltage at startup would typically be 11.7. It was 12.2v this noon with the replacement battery. Assuming the replacement battery doesn't also require warranty replacement' my next battery will be an AGM. It is my understanding AGM batteries are better for hybrids because they handle frequent starts and stops better.

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[Master Blaster]

As stated in a prior post, Ford replaced with the same type (warranty and not AGM); it appears to be marginally better. Had not driven the Mav for 2 days. Before replacement the voltage at startup would typically be 11.7. It was 12.2v this noon with the replacement battery. Assuming the replacement battery doesn't also require warranty replacement' my next battery will be an AGM. It is my understanding AGM batteries are better for hybrids because they handle frequent starts and stops better.

The 12V battery does not do anything serious in relation to the start/stop cycling. It runs the vehicle electronics, including the computers and relays involved in getting the high-voltage battery to do all the heavy lifting. An AGM is not very suited to this task, which is probably why they switched to a normal lead-acid battery. For twice the price, and AGM will give you maybe 10% better reserve capacity, which is the only number that counts on the Hybrid. I agree that an AGM battery would be a better choice for the EcoBoost though.

 

[Cherokee]

An AGM came in my 2024 Ecoboost

 

[Ozarkbeard]

The 12V battery does not do anything serious in relation to the start/stop cycling...

Absolutely true on the Hybrid. The ICE in the Hybrid is started with the starter/generator motor inside the transmission. It uses the HV battery (not the 12v battery) for starting power.

 

[Matso]

Just to be clear, the 12v battery in the hybrid is absolutely necessary to start the vehicle. If the voltage drops to a particular point ( I do not know that exact threshold), you're not going anywhere. You will have to jump it with an external power source. Now whether or not the 12v just powers the electronics to initiate start by the HVB or energizes the starter motor directly seems to be a matter of debate. I say this because when asking a service advisor this very question, he said the vehicle starts using the 12v. Whatever that meant.
More to come on this subject I'm sure.

 

[Suzukiridr14]

Just to be clear, the 12v battery in the hybrid is absolutely necessary to start the vehicle. If the voltage drops to a particular point ( I do not know that exact threshold), you're not going anywhere. You will have to jump it with an external power source. Now whether or not the 12v just powers the electronics to initiate start by the HVB or energizes the starter motor directly seems to be a matter of debate. I say this because when asking a service advisor this very question, he said the vehicle starts using the 12v. Whatever that meant.
More to come on this subject I'm sure.

Everyone seems to mention starting problems with a hybrid, with the starting motor. The hybrid doesn't have a starting motor, it starts through the eCVT.

 

[svogt302]

The 12V battery does not do anything serious in relation to the start/stop cycling. It runs the vehicle electronics, including the computers and relays involved in getting the high-voltage battery to do all the heavy lifting. An AGM is not very suited to this task, which is probably why they switched to a normal lead-acid battery. For twice the price, and AGM will give you maybe 10% better reserve capacity, which is the only number that counts on the Hybrid. I agree that an AGM battery would be a better choice for the EcoBoost though.

Why is an AGM not suited for that task?
My Ranger (start/stop) came with an AGM Battery.

 

[HeyBales]

Why is an AGM not suited for that task?
My Ranger (start/stop) came with an AGM Battery.

Because all it does is provide the power for the micro-draw when not running (unlock system, alarm, TCU), and close some contacts for the HVB to come online.

Or if you use Acc mode a lot with lights on and radio playing. That drains the 12V battery like any vehicle.

Perhaps not-suited in this case means big overkill for requirements.

There is no auto-start/stop in hybrids like the Ranger.

 

[HeyBales]

Just to be clear, the 12v battery in the hybrid is absolutely necessary to start the vehicle. If the voltage drops to a particular point ( I do not know that exact threshold), you're not going anywhere. You will have to jump it with an external power source. Now whether or not the 12v just powers the electronics to initiate start by the HVB or energizes the starter motor directly seems to be a matter of debate. I say this because when asking a service advisor this very question, he said the vehicle starts using the 12v. Whatever that meant.
More to come on this subject I'm sure.

At 9.5 V or less the deep sleep mode is brought in to turn off the TCU, in the hopes that whatever amount of time until you start the truck - there will be juice to do so.

And the receiver for constantly listening for the unlock from key fob is still going also. Perhaps that eventually drops off-line too.

So less than 9.5 V must be enough, by some amount.

So it's probably wise - if you got the deep sleep alert (which could be for 3 reasons) - don't get in the truck, turn on the lights and radio, and dink around for 10 minutes before you start it. By that point using the 12V system, you may have ruined your chance.

 

[HeyBales]

As stated in a prior post, Ford replaced with the same type (warranty and not AGM); it appears to be marginally better. Had not driven the Mav for 2 days. Before replacement the voltage at startup would typically be 11.7. It was 12.2v this noon with the replacement battery. Assuming the replacement battery doesn't also require warranty replacement' my next battery will be an AGM. It is my understanding AGM batteries are better for hybrids because they handle frequent starts and stops better.

That 12V battery isn't used for any engine starting.
It's the HVB powering the generator motor if sitting and temps are low enough, it's the generator motor if you are moving powered by the traction motor.

 

[Master Blaster]

Why is an AGM not suited for that task?
My Ranger (start/stop) came with an AGM Battery.

You Ranger uses the 12V battery to start the engine. The Hybrid Maverick does not. The cranking power rating is completely irrelevant on the Hybrid. The only number that matters is the reserve capacity. Since an AGM does not have a lot more reserve capacity for its doubled price, its not the smartest move.

 

[Raymundo76]

That 12V battery isn't used for any engine starting.
It's the HVB powering the generator motor if sitting and temps are low enough, it's the generator motor if you are moving powered by the traction motor.

Never said it did. Frequent starts and stops of the gas engine maybe hard on the lead-acid battery that is not an AGM. Also the BMS appears to under charge the gas engine battery

 

[Raymundo76]

The 12V battery does not do anything serious in relation to the start/stop cycling. It runs the vehicle electronics, including the computers and relays involved in getting the high-voltage battery to do all the heavy lifting. An AGM is not very suited to this task, which is probably why they switched to a normal lead-acid battery. For twice the price, and AGM will give you maybe 10% better reserve capacity, which is the only number that counts on the Hybrid. I agree that an AGM battery would be a better choice for the EcoBoost though.

It is not that the battery does anything to the starting and stopping; rather that frequent starts and stops of the gas engine maybe hard on the battery. Some references have stated that an AGM battery might be better for that case, charges quicker, and has better reserve capacity. Also some members have stated that the 25 hybrids have AGM batteries; if true why did Ford make that change ? All I am sure of is the the original battery always had a very low voltage, and the BMS seems to starve it in favor of the hybrid batteries. It is possible that the stock battery on my 24 hybrid was just a crappy Mexican battery. Thanks for your input.

 

[Darnon]

Everyone seems to mention starting problems with a hybrid, with the starting motor. The hybrid doesn't have a starting motor, it starts through the eCVT.

You know what's in the eCVT? A motor (two of them, in fact) one of which has the duty of... starting the engine. A starting motor you might say.

 

[HeyBales]

Never said it did. Frequent starts and stops of the gas engine maybe hard on the lead-acid battery that is not an AGM. Also the BMS appears to under charge the gas engine battery

That's what I mean - there's a fundamental misunderstanding of how that works.

There is no direct connection between the two - engine and 12VB.

12VB touches a relay, and is charged from the DCDC Conv.

Engine touches a generator motor that feeds the DCDC Conv, along with the HVB and traction motor.

The ICE being started and stopped has no effect on the 12VB.

Yes the BMS is an issue.
But even the term gas engine battery is incorrect. It's not.

But the BMS isn't starving the 12VB in favor of the HVB, again a misunderstanding of how it works.

Mine's a small Spain made 12VB.

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