Hybrid battery drain issue / ACCM update (as of 11/8/25) -- Latest info from a tech's perspective

[HeyBales]

ryobi charger, I will leave on all night tonight, see what it does in morning. thank you

I see only a 2A charger from them.
So if it's similar to my Noco 2A charger - it says it'll charge up to a 40 Ah battery.
But even the smaller hybrid version was a 45 Ah - so it'll take longer to eventually get there.

You'll still have to turn truck on for a bit to register higher voltage, and disable the battery saver functions.
And then the next night - if you can leave it locked for 10 hrs to do a BMS Relearn - important too.

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[Prickly Pear]

Ford just sent me my "happy one year anniversary" survey. I gave them one star - I would never recommend Ford, and let my feelings about the battery be known.
It probably won't matter and I've been bragging up the truck anyway

 

[ice445]

Has anyone tried pulling fuse 11 and seeing if that helps? I doubt it does but I cant help but be curious lol

 

[BLUEOVALRACER]

I don't know for sure. But typically Ford eventually issues a "recall" which in essence is an extension of the warranty. They may say that it's covered until x miles and y time. But they'll also say that if the vehicle has excee

It literally takes about 10 minutes. I spent more time getting the parts, and pulling it inside the shop and writing it up after it was done than the actual repair. If you get your oil changed at the dealership, that's a convenient time to have it done.

Thanks I was thinking about having the Recall done when I get the Oil Changed.

 

[HeyBales]

Has anyone tried pulling fuse 11 and seeing if that helps? I doubt it does but I cant help but be curious lol

It has helped many.

 

[Msradke]

System needs to know full voltage after charge. You need to to do battery reset. in owners manual

 

[Deb from MN]

thank you everyone, all greek to me I'm learning!

 

[wax87]

This is really good to hear. I will say this. I can drive my truck non-stop from Orange County CA to Lake Havasu and back home, running the AC, and I will most likely get the "Sleep Mode" message the next morning. Thats just under 9 hours round trip driving.

If I drive the truck for weeks at a time, doing stop and go driving and I don't run the AC, ......no messages. The AC system has to have something to do with the drain.

So if you turned off the AC when you turn off the Maverick, would that stop the drain?

 

[CurtisB]

So if you turned off the AC when you turn off the Maverick, would that stop the drain?

I always manually shut off the AC. The difference that I have observed is that driving stop and go with no AC means no "sleep messages." Driving for 9 hours with the AC on, guarantees a "sleep" message the next morning. I hope this answers your question?

 

[HeyBales]

System needs to know full voltage after charge. You need to to do battery reset. in owners manual

Actually no - that's after a new battery.
All that does is reset a bunch of tracking figures back to 0. One being battery age in days.

If Ford tries to do the charging algorithm like others - and they probably attempt to - a newer battery requires less current than an older battery, less resistance inside.

So another negative to doing the BMS Reset described in manual after you put in a new battery - when you don't actually put in a new battery - is likely less current because BMS has been told you have a new battery.

Just do the BMS Relearn - which is how it figures out SOC%.
Voltage it knows on every start, that doesn't take anything special.

 

[bighap]

So if you turned off the AC when you turn off the Maverick, would that stop the drain?

I live in a very mild climate and have ceramic tint on every window, including the windshield so I rarely use the AC. It made no difference for me. Get the AC software update and an AGM battery and call it a day.

 

[Msradke]

Actually no - that's after a new battery.
All that does is reset a bunch of tracking figures back to 0. One being battery age in days.

If Ford tries to do the charging algorithm like others - and they probably attempt to - a newer battery requires less current than an older battery, less resistance inside.

So another negative to doing the BMS Reset described in manual after you put in a new battery - when you don't actually put in a new battery - is likely less current because BMS has been told you have a new battery.

Just do the BMS Relearn - which is how it figures out SOC%.
Voltage it knows on every start, that doesn't take anything special.

After 50 years of repairing vehicles and noting that some things still not working after charging a battery to full charge. You should do a BMS reset for systems to know full voltage has been restored. I have charge my battery and still had concerns which were corrected after a BMS reset. I have also discussed it with several other techs I know.

 

[Darryl]

After 50 years of repairing vehicles and noting that some things still not working after charging a battery to full charge. You should do a BMS reset for systems to know full voltage has been restored. I have charge my battery and still had concerns which were corrected after a BMS reset. I have also discussed it with several other techs I know.

I've had vehicles come in where the system went into sleep mode too quickly, or the "system switching off to preserve battery " message came on after only a minute or so when sitting listening to the radio. And the only thing that would fix it was a BMS reset. It has become one of my first go to's when I have a vehicle with strange electrical issues. Yes. I know the official recommendations of only resetting it when the battery is replaced. But I also know what actually happens. Doing a reset on an old battery has never had any negative effects as far as I've noticed. But it has solved a few issues. As a tech, that's what matters. With the Maverick hybrid charging system, changing the charging strategy to charge faster or more fully would only be a cover up anyway since the problem is that the battery drains more deeply than it should due to the excess draw. The battery would still semi deep cycle. That's what wears the battery out prematurely. In the meantime, i recommended that the owner of a Maverick with an excess draw problem have the AC module update performed since that fixes many of them. Install an AGM battery if it's out of warranty since they're more tolerant of discharge cycles. Do a BMS reset from time to time if it seems to help. And periodically check with the dealership to see if Ford has released any new fixes. If still under warranty, bring it in at least twice to have a record of repeated repair attempts, and start the truck daily and let it run at least 20 minutes even if you don't need to use it. I believe Ford will EVENTUALLY fix this.

 

[2seater]

I find that my hybrid which sleeps for the winter, connected to a battery maintainer, will not turn the dome lights on after a few days of inactivity. No battery saver mode indicated on the Ford app. Green light indicating full charge on the maintainer but no dome or dash lights. I didn't check other functions. It just seems to me to be a very complex issue that is somehow baked in and it really lets an otherwise fine product get a black eye. It did the same thing last year.

 

[Probity]

And the only thing that would fix it was a BMS reset. It has become one of my first go to's when I have a vehicle with strange electrical issues.

In the meantime, i recommended that the owner of a Maverick with an excess draw problem have the AC module update performed since that fixes many of them. Install an AGM battery if it's out of warranty since they're more tolerant of discharge cycles. Do a BMS reset from time to time if it seems to help. And periodically check with the dealership to see if Ford has released any new fixes.

If still under warranty, bring it in at least twice to have a record of repeated repair attempts, and start the truck daily and let it run at least 20 minutes even if you don't need to use it. I believe Ford will EVENTUALLY fix this.

An interesting thread. Not a Mav hybrid owner yet but still thinking I will be in not too distant future. The whole Ford BMS (and inter-related electrical components) mess must be absolute hell on Ford service techs, the amount of trouble-shooting and frustration involved is astounding as evidenced by your posts. Owners are PO'd, take it to dealerships hoping for a 'fix', Darryl & his compatriots can't always resolve it, customers vent their spleens at Darryl/dealerships, rinse and repeat. I don't envy the position you're in.

To state the obvious - Ford's not alone in BMS-related woes. Check out Hyundai, Toyota forms sometimes, much of the same. For some strange reason I don't see a lot of BMS dirty laundry aired on GM truck forums I belong to, don't know why other than maybe a radically different BMS software/logic system in them, IDK.

All I can do is thank you for speaking up on your experiences and findings, people like you are the ones that can ultimately make Ford a success, appreciate your efforts and keep up the good work.

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