Question about 12V Battery

[dchan]

Anyone with a Hybrid or PHEV notice that if you don't do long drives, that the vehicle keeps going into "power save" or even "Deep Sleep" mode after a short drive.

I suspect that the short 7-9 mile drives back and forth across town are not enough to really charge the 12V battery. Especially if I'm driving real carefully and keeping the vehicle in Electric as much as possible.

There have been several times where, as soon as I park my Escape and hit the "engine off" button, it immediately goes to "power save" even after driving all the way across San Francisco.

I do get the message in Ford Pass, that my vehicle's remote functions will not work, but nothing is wrong.. That it's common for this to happen when you have not driven the car in a while.

When I did a long drive (380Mi round trip) the symptom went away for a couple weeks. Now it's back to doing it again right after I park the vehicle..

Guess I have to drive it harder so that the engine keeps running? Kind of defeats the purpose of driving it while trying to capture as much recovery energy as possible. but It is fun getting 50+ MPG driving the HEV across town!

Can I put the 12V battery on a trickle charger at night?

 

 

[dchan]

Oh. I did find this over on the Ford Escape forum

https://www.fordescape.org/threads/2020-ford-escape-hybrid-replace-12-volt-battery-with-larger-group-48-agm.117248/page-9

 

[j2sys]

18 hours ago, dchan said:

Guess I have to drive it harder so that the engine keeps running? Kind of defeats the purpose of driving it while trying to capture as much recovery energy as possible. but It is fun getting 50+ MPG driving the HEV across town!

 

The hybrid's high voltage battery (HVB/traction battery) is charged through regen braking and by siphoning off power from the engine.

 

The conventional 12V battery is not charged via a traditional alternator off the engine.  Instead, it's charged off the HVB via the DC-DC converter.  So long as the vehicle is running (even with the engine off), it will recharge the 12V battery.  In other words, there's no reason to force the engine on.

 

The problem is that the 12V battery is small and slow to charge, and various systems that keep running after the vehicle is turned off (including the FordPass modem) drain it quickly.  Every time you go out to the vehicle when it's parked to load/retrieve something, it drains the battery.  The longer you leave the infotainment system running before you turn the vehicle on or after you turn it off, the more it drains the battery.  And this battery doesn't have much margin to give.

 

In time, you notice that the infotainment system turns off much more quickly after you turn off the vehicle.  The interior/exterior lights don't stay on as long.  The passenger side intelligent access door handle does not respond when you grab it to unlock.  The interior lights don't turn on when you open the door.  All of these are signs that the BMS - Battery Management System - is kicking in its protections to keep you from draining the 12V battery where the vehicle won't start next time you need it.  These are all symptoms of the tiny battery -- plus some of them may well have defective cells and actually have even less capacity than designed.

 

As you've found, other Escape owners have ditched the factory battery for a larger 48H6 battery, switching from a conventional flooded lead acid to an AGM type.  The bigger battery has more capacity, more margin, and AGM is said to charge more quickly.  On Escape, it should be a drop-in replacement as there's plenty of room back there.

Edited July 16, 2023 by j2sys

[dchan]

Thank you for the explanation. I had not dug into the charging systems yet. That helps and explains more about why I'm seeing the behavior you mention. An AGM may be in my future. or even a LiFePO? Anyone try one of those yet?

 

[dchan]

On 7/16/2023 at 10:59 AM, j2sys said:

The conventional 12V battery is not charged via a traditional alternator off the engine.  Instead, it's charged off the HVB via the DC-DC converter.  So long as the vehicle is running (even with the engine off), it will recharge the 12V battery.  In other words, there's no reason to force the engine on.

 

 

I need to do more research on this but according the few articles I read, on some hybrids, While they use DC-DC charging for the 12V system, many require the ICE engine running to enable the DC-DC charge unit.

If this is the case along with the small slow charging battery, it may be why I don't get enough of a charge on the 7 mile drive across the city. A couple times I drove the seven miles with about 6 miles electric. (Hybrid not PHEV) Last several blocks were in a tunnel so of course the headlights are on and downhill so I'm almost always on electric this part of the drive.
As soon as I parked, the vehicle went right into deep sleep.

 

[silvrsvt]

On 7/16/2023 at 1:59 PM, j2sys said:

As you've found, other Escape owners have ditched the factory battery for a larger 48H6 battery, switching from a conventional flooded lead acid to an AGM type.  The bigger battery has more capacity, more margin, and AGM is said to charge more quickly.  On Escape, it should be a drop-in replacement as there's plenty of room back there.

 

Why are they using an AGM style battery on regular ICE engines and not the hybrids from the factory? That doesn't make much sense and indicates that there is some sort of reason why Ford is doing it. 

 

I know why its being using with ICE-its due to the stop start system, but if not being used on hybrids, that makes me wonder. 

[rperez817]

29 minutes ago, silvrsvt said:

Why are they using an AGM style battery on regular ICE engines and not the hybrids from the factory? That doesn't make much sense and indicates that there is some sort of reason why Ford is doing it. 

 

Cost. Hybrids don't rely on the 12V battery for automatic start-stop functionality for the IC engine. Why should Ford waste money on a more expensive AGM 12V battery?

[j2sys]

3 hours ago, silvrsvt said:

 

Why are they using an AGM style battery on regular ICE engines and not the hybrids from the factory? That doesn't make much sense and indicates that there is some sort of reason why Ford is doing it. 

 

I know why its being using with ICE-its due to the stop start system, but if not being used on hybrids, that makes me wonder. 

 

Cost, of course.  Same reason that the factory uses an even smaller battery than the 99RT4 specced in the manual.  Also, 2020 Escape manual listed 99RT4 for hybrid, then 2021 listed 48H6 AGM, only to see 2022+ reverted to 99RT4.  Even though, best I can tell, they never installed the larger AGM battery at the factory.  Of course, even pointing this out to the dealer won't get them to push Ford to cover the 48H6 AGM as a replacement when the factory battery inevitably shows its flaws...  Maybe if you have a 2021.

 

Do bear in mind that, as noted, the 12V battery is not a starter battery.  It powers the low voltage electronics, including closing the contactors on the HVB.  The HVB starts the ICE by spinning up the eCVT.  So Ford's excuse is that hybrids don't need much of a battery, except that neglects all the electronics that run on these modern vehicles, including long after they're turned off, continuing to drain the battery.

 

On the other hand, an Escape EcoBoost's engine start/stop feature does use the 12V battery as a starter battery and needs to be able to power the electronics with the engine off - it has no possible charge source other than to fire the ICE back up.  Even then, at least with Maverick EB, they've used both AGM and FLA batteries interchangeably for no apparent rhyme or reason except perhaps supply chain issues.

Edited July 18, 2023 by j2sys

[dchan]

Definitely sounds like a group 48 AGM is in my future. Even If I have to put it in myself. When I drove 30+ miles mostly freeway, but drove it very carefully so that I was running electric a lot of the way, it only took about 2 minutes of me listening to the radio upon arrival for my vehicle to go to "deep sleep" mode. I did get about 52MPG on the 30mi trip which was kind of cool!

I would like to be able charge my phone or other items from time to time without having to start the engine up.

 

[dchan]

So I bit the bullet..

Installed an Interstate Group 48 AGM Battery in my Hybrid. Since then I have not seen any of those deep sleep mode messages. It's been about a week now. Will continue to check in as my experience grows.

It was an easy fit although the cables are almost too short to make the connection. The battery hold down moved over to the other nut with no problems. Spare still fits over the top no problem, The only mechanical issue was that the "cover" that has the spare hold down bolt, had a small tab to keep the old 45AH battery from sliding over. It's pretty thin gauge metal so it was easy to gently bend out of the way.


 

[dchan]

Since I installed the new Group 48 AGM I have not had the deep sleep notification. Looks like that solved it.

Now if I can just figure out where to control the USB ports. The rear ones (behind the center console in the passenger area) keep going to sleep even when I'm driving.