Ford BMS Battery Monitoring System: How it Works, How to Properly Charge, How to Power Accessories

[sajohnson]

Have always had my trickle charge hooked up to the terminals as detailed when I installed it:
https://www.broncosportforum.com/forum/threads/project-obronco.2688/post-47293

No issues. I charge with the vehicle off anyhow. I don't know why the video is charging koeo other than to demonstrate that the sensor operates. When you restart the car, it's going to recalculate the battery charge. Video admits the car recalculates state of charge every few hours regardless. If there was any other effect, there would be some complicated procedure to calibrate after a battery replacement. I think the point about not grabbing loads directly off the battery is the most important part.

You may be aware of this but just in case -- from the manual:

Battery Sensor Reset:

"When you install a new battery, reset the battery sensor by doing the following: 1. Switch the ignition on, and leave the engine off. Note: Complete Steps 2 and 3 within 10 seconds. 2. Flash the high beam headlamps five times, ending with the high beams off. 3. Press and release the brake pedal three times. The battery warning lamp flashes three times to confirm that the reset is successful."

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[sajohnson]

Battery Sensor Reset (Battery Management System (BMS) Reset):
When you install a new battery, reset the battery sensor by doing the following:
1. Switch ignition on, and leave the engine off.
Note: Complete Steps 2 & 3 within 10 seconds.
2. Flash the high beam headlamps five times, ending with the high beams off.
3. Press and release the brake pedal 3 times.
The battery warning lamp flashes 3 times to confirm that the reset is successful.

I just saw this after posting (#31). Great minds!

 

[Jrl]

Glad you stuck to your guns. We pay a lot of money for the warranty that Ford provides for these vehicles. If you allow someone to talk you out of using it then you are giving away something you paid for.

For the record, both AGM and gel-type batteries are types of valve-regulated lead-acid (VRLA) batteries. These are often referred to as "maintenance free" or "sealed" because unlike conventional flooded cell batteries, they normally do not require the addition of chemical electrolyte over their lifetimes. The reason they are called "valve-regulated" batteries has to do with a safety feature (a valve) that allows venting of gases should pressure in the battery exceed safe levels. This can happen in the event of overcharging, or an internal failure that results in overcharging of one or more of the battery's cells.

This is one of the reasons you should always first connect the positive clamp to the battery's positive terminal, then the ground clamp to the chassis ground when using a battery charger or when jump starting a discharged battery. The last clamp connected might generate a spark, and gases coming from a battery's emergency vent valve are combustible.

So if I go away for a couple months can I leave it on a trickle charger for the time I will be gone ? Thanks

 

[Mark S.]

So if I go away for a couple months can I leave it on a trickle charger for the time I will be gone ? Thanks

Should your battery charger malfunction and send more than 14 volts to your battery there is a chance it could overcharge. Chargers with a maintenance function should have built-in circuitry to safeguard against such malfunctions. If your charger does not have a maintenance function then you should probably not use it unsupervised.

You might consider using your charger as a test before leaving it for extended times. There are fairly obvious signs you can look for to check if your batter is overcharging:

https://www.toc.edu.my/automotiveandmotorsports-hub/2023/how-do-you-know-if-your-car-battery-is-overcharged

 

[Jrl]

Should your battery charger malfunction and send more than 14 volts to your battery there is a chance it could overcharge. Chargers with a maintenance function should have built-in circuitry to safeguard against such malfunctions. If your charger does not have a maintenance function then you should probably not use it unsupervised.

You might consider using your charger as a test before leaving it for extended times. There are fairly obvious signs you can look for to check if your batter is overcharging:

https://www.toc.edu.my/automotiveandmotorsports-hub/2023/how-do-you-know-if-your-car-battery-is-overcharged

Sorry Mark i neglected to say I had bought a trickle charger . So then i will be ok ? And also thanks for the above tech very informative.

 

[Mark S.]

Sorry Mark i neglected to say I had bought a trickle charger . So then i will be ok ?

Should be good to go, but you might run a test for a few days and look for signs of overcharging to be sure.

 

[sajohnson]

Sorry Mark i neglected to say I had bought a trickle charger . So then i will be ok ? And also thanks for the above tech very informative.

What is the make and model?

The reason I ask is that some 'trickle chargers' have a fixed output, and even though it may be relatively low it can evaporate the electrolyte/acid over time.

The "Battery Tender" brand is established and safe. So is "Battery Minder". They cost more, but they are 'smart' chargers that protect the battery from being overcharged.

I'm sure there are others. Those are 2 I'm familiar with. I have several different BT models.

EDIT: We leave a BT on both our RV and Suzuki DRZ 24/7. The OE Sprinter battery lasted 10 years (and was still OK) and the OE Suzuki battery lasted 6 years.

 

[Jrl]

What is the make and model?

The reason I ask is that some 'trickle chargers' have a fixed output, and even though it may be relatively low it can evaporate the electrolyte/acid over time.

The "Battery Tender" brand is established and safe. So is "Battery Minder". They cost more, but they are 'smart' chargers that protect the battery from being overcharged.

I'm sure there are others. Those are 2 I'm familiar with. I have several different BT models.

EDIT: We leave a BT on both our RV and Suzuki DRZ 24/7. The OE Sprinter battery lasted 10 years (and was still OK) and the OE Suzuki battery lasted 6 years.

What I bought is a cen-tech model 59000 at harbor freight it is called a 12 volt automatic battery charger and maintainer . Thanks again

 

[Jrl]

Should be good to go, but you might run a test for a few days and look for signs of overcharging to be sure.

This is what i bought. Thanks

 

[Jrl]

Should be good to go, but you might run a test for a few days and look for signs of overcharging to be sure.

This is were I connected the negative cable clamp on the flat part I have indicated. Thanks

 

[sajohnson]

What I bought is a cen-tech model 59000 at harbor freight it is called a 12 volt automatic battery charger and maintainer . Thanks again

Looks OK (if we can believe the mfr claims).

I've purchased a couple things from HF over the years. They are alright for certain items, but they sell some very low quality products as well.

If you haven't done so, you might consider checking reviews of the 59000. Here's one forum thread:
https://www.garagejournal.com/forum/threads/battery-maintainer.487434/#post-9256232

Nothing earthshaking and a different model HF maintainer, just an example. Like other forums, GJ can be helpful but you have to 'separate the wheat from the chaff.'

The model 59000 may be fine, but without more info, I'd personally be inclined to go with "Battery Tender" or "Battery Minder". They do cost more though. Money is always a consideration, but as I've gotten older I'm more inclined to spend more for name brand products and (usually) OEM auto parts.

That said, if the HF maintainer is good, then you're money ahead.

 

[ZQ8]

For owners that have had to change their battery, does the air filter housing have to be removed to do it ?

 

[coopny]

For owners that have had to change their battery, does the air filter housing have to be removed to do it ?

Yes. Confirmed via youtube for 1.5L:


2.0L when on Advance Auto Parts says they won't install the battery and lists removal of the engine air filter housing as the reason.

It doesn't look terrible if you have the tools, but it does require some amount of effort.

 

[Jenma]

chassis grounded battery maintainer and antenna

I spent an hour + looking for that clamp. Could you tell me where to find one?

 

[Major Kong]

I spent an hour + looking for that clamp. Could you tell me where to find one?

this is the lug used in the grounding application
battery maintainer and antenna utilize the lug
additional note: the frame mounted ground post has a raised lip (see pic)
this lip puts the lug at a slightly less than perfect fit

a small amount work with the dremel tool removed enough lug material
at the lip meets lug contact point

also added to the anchor screw
one hex nut to act as a lock down nut to secure no-worry ground

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