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

[Administrator]

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

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[HSV_MIkeJ]

Good info, still think a higher capacity battery should be in these trucks so when you do drive it for longer periods it can build up a higher reserve capacity.

Mine does have the 760 CCA battery, but have seen Spec sheets that says the Lariat and above should have an 800 CCA battery installed if it has the EcoBoost V6 or a 850 CCA for the Turbo Diesel.

 

[Doughecka]

Excellent video, I'd be curious to see how the PowerBoost handles this... can the traction battery keep the AGM topped up when the truck is off? Or can it supply enough current fast enough to offset the 12V demand during short drives?

 

[Dwag21]

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

Thank you for the information! My questions are in the video you point out to hook up accessories and battery chargers before the bms yet when u charge it looks like you are clamping it after the bms box.
Can i hook up to the post where you have it clamped for successful charging with the negative and still have the positive directly attached to positive battery post and the bms will recognize and manage my accessories?

Thank you for your time

 

[FirstFord]

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

Excellent video - well done! It answers numerous questions that I had regarding BMS, but for me, it also raises a question.... It was stated several times (as well as graphically demonstrated on the laptop) that the truck was drawing 18A just sitting there, implying 18 parasitic amps. Wow! I was shocked by that - that's a lot! It also means that a traditional so-called "smart charger" (battery maintainer) would be of little use since most are rated at 5A or less. But at the end of the video, he then goes and turns the ignition off. What? The ignition was "ON" all of that time? When the ignition is "ON", most of the systems are energized, whereas most are not when the ignition is turned "OFF". So, I have to conclude - or at least assume - that when the truck is truly SHUT DOWN, it is not drawing 18A. Now I wonder what the true parasitic loss of energy really is....

I am really interested in this because I do not drive my truck daily - I drive it when I actually need a truck. So, it may be driven daily, or it may sit for several days - or even a week or so - without being driven. For the first time, I had an experience similar to what was explained in the video. I went to the truck to get something out. None of the approach lights came on; I opened the door, and there were no interior / dome lights. I suspected right away that the BMS was doing its job and shut most everything down. Fortunately, it started just fine, but it did raise my awareness of real-life battery drain and I would like to address it - but now I'm not really sure how. Put a full-bore shop battery charger on it every other week? That's kind of a hassle.... Or am I approaching this thing with some wrong-minded thinking?

 

[My 2ND Ford]

Excellent video - well done! It answers numerous questions that I had regarding BMS, but for me, it also raises a question.... It was stated several times (as well as graphically demonstrated on the laptop) that the truck was drawing 18A just sitting there, implying 18 parasitic amps. Wow! I was shocked by that - that's a lot! It also means that a traditional so-called "smart charger" (battery maintainer) would be of little use since most are rated at 5A or less. But at the end of the video, he then goes and turns the ignition off. What? The ignition was "ON" all of that time? When the ignition is "ON", most of the systems are energized, whereas most are not when the ignition is turned "OFF". So, I have to conclude - or at least assume - that when the truck is truly SHUT DOWN, it is not drawing 18A. Now I wonder what the true parasitic loss of energy really is....

I am really interested in this because I do not drive my truck daily - I drive it when I actually need a truck. So, it may be driven daily, or it may sit for several days - or even a week or so - without being driven. For the first time, I had an experience similar to what was explained in the video. I went to the truck to get something out. None of the approach lights came on; I opened the door, and there were no interior / dome lights. I suspected right away that the BMS was doing its job and shut most everything down. Fortunately, it started just fine, but it did raise my awareness of real-life battery drain and I would like to address it - but now I'm not really sure how. Put a full-bore shop battery charger on it every other week? That's kind of a hassle.... Or am I approaching this thing with some wrong-minded thinking?

What you need is a 1.5 amp to 5 amp trickle charger/maintainer. Hook it up like it is shown in the video, plug it in , close the hood and walk away. There is plenty of info on this subject in this forum. I have a 1.5 amp battery tender, that is the brand and I have been using it since I got my truck in July of 2021. Others on this forum have used the NOCO brand. Both are excellent units. A larger unit will simply bring the battery to full charge sooner.

 

[FirstFord]

What you need is a 1.5 amp to 5 amp trickle charger/maintainer. Hook it up like it is shown in the video, plug it in , close the hood and walk away. There is plenty of info on this subject in this forum. I have a 1.5 amp battery tender, that is the brand and I have been using it since I got my truck in July of 2021. Others on this forum have used the NOCO brand. Both are excellent units. A larger unit will simply bring the battery to full charge sooner.

Thanks for your reply. I am quite aware of the NOCO battery charger products, as I own several of them - and like the other forum posters, I too think they are excellent products.

My point was that according to the BMS educational video, there is a constant 18 amp draw (although I find that figure somewhat questionable, since the ignition was "ON"), and as the author stated - and demonstrated on the laptop - a 5 amp or even 10 amp charge still leaves the battery in a negative charge state. He had to turn the charger up to a minimum of 20 amps to overcome the 18A parasitic draw, yielding a 2A charge - the equivalent of a trickle charger. In other words, it takes a 20A charger to yield a 2A positive charge.

First, I am unaware of any 20A or larger battery maintainers. Secondly, this is all based on the video saying there is an 18A drain, which I really question, and THAT may be my underlying issue. Yes, there are many posts on this topic, as you have pointed out, but the 18A draw changes the discussion, IMHO. So, I'm still kind of lost as to how to proceed.

 

[Old Bear]

Thanks for your reply. I am quite aware of the NOCO battery charger products, as I own several of them - and like the other forum posters, I too think they are excellent products.

My point was that according to the BMS educational video, there is a constant 18 amp draw (although I find that figure somewhat questionable, since the ignition was "ON"), and as the author stated - and demonstrated on the laptop - a 5 amp or even 10 amp charge still leaves the battery in a negative charge state. He had to turn the charger up to a minimum of 20 amps to overcome the 18A parasitic draw, yielding a 2A charge - the equivalent of a trickle charger. In other words, it takes a 20A charger to yield a 2A positive charge.

First, I am unaware of any 20A or larger battery maintainers. Secondly, this is all based on the video saying there is an 18A drain, which I really question, and THAT may be my underlying issue. Yes, there are many posts on this topic, as you have pointed out, but the 18A draw changes the discussion, IMHO. So, I'm still kind of lost as to how to proceed.

On other threads I have seen reports that when you first shut off the truck, the high draw continues for a short while. After a short period however (10, 15 minutes?) modules start shutting themselves off and you end up with a draw of less than an amp. No problem for a tender to overcome that.

 

[FirstFord]

On other threads I have seen reports that when you first shut off the truck, the high draw continues for a short while. After a short period however (10, 15 minutes?) modules start shutting themselves off and you end up with a draw of less than an amp. No problem for a tender to overcome that.

Okay, now we're getting somewhere! If those reports are accurate, then that would explain a lot of things, including the mysterious 18A parasitic draw of power. It would also mean that a regular 2A~5A battery maintainer would be sufficient after all, as you and others have suggested.

 

[Snakebitten]

Service Manual states that when troubleshooting a parasitic draw on a Powerboost, the tech is to shutdown the truck, lock doors, remove key Fob from area, and wait 75 minutes.

Draw should be 500ma (.5 Amp) or less.
I'm pretty sure my truck is drawing more than that on many occasions. I just haven't made the effort to troubleshoot it yet.
It's not every night, but random.

 

[RcFlyer330]

Okay, now we're getting somewhere! If those reports are accurate, then that would explain a lot of things, including the mysterious 18A parasitic draw of power. It would also mean that a regular 2A~5A battery maintainer would be sufficient after all, as you and others have suggested.

One reason for the ignition to be on in the video is because the scantool needs the ignition on to view the bms current pid. With the ignition off and all modules shut down the draw should be less than 500mA as Snakebitten said. a battery matainer 2-5A will be able recharge the battery and keep it charged.

 

[PaulGrun]

okay, I have some questions. Here's the hypothetical situation: left the truck in the driveway, undriven, for a month and a half. At the end of that period, the battery is dead (hypotehtically). Completely dead.​

First question: is that battery (in a truck that is a few months old) now an unrecoverable boat anchor, given that it's (hypthetically) down under 5 volts? (Under normal circumstances, I would say that a battery at that low of a charge has had the polarity on at least a couple of cells reversed, rendering it useless.)​

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Assuming that the battery is somehow not completely toast, shall I assume that simply jumping the vehicle and driving it around is insufficient to re-build that battery, and that the only hope of recovery (a faint hope, at best) is via an external charger?​

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And if an external charger is my only hope, will my 1.25A Battery Tender do the job, or do I need to go out and buy a beefier one?​

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Here's my complaint: I have a hard time imagining an electrical system that is so fragile that it allows the battery to commit suicide because the owner committed the grave sin of failing to drive the vehicle for a month or so.​

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It seems to me that if these vehicles *really* require the regular assistance of a battery charger, that Ford ought to include one in the purchase price (tongue in cheek, of course). Or at the very least there ought to be warnings ALL OVER the owners manual about the risks of not driving your truck for a little while. (Yes, I know that there is a short section on vehicle storage if you're leaving the truck for more than a month or so. But come one, who has EVER in the history of modern automotives worried about leaving a vehicle sitting for a month or more? Heck, last spring I left a Subaru Outback and a BMW sitting for three months with zero ill-effects.​

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And to the OP, thank you for posting this video ... it cleared up a lot of things for me, even if they are things that honestly a consumer shouldn't have to be worried about.​

 

[Snakebitten]

There are many makes and models of vehicles that are notorious for needing their batteries on some kind of maintainer if they are going to sit for any length of time. A month would certainly be a "length of time".

Visit a Porsche forum.
I have a 2005 Porsche with a tiny fraction of the electronics my 2022 Powerboost has.

I'm not actually complaining about the F150 battery needing a trickle charger if I'm going to let it sit. But I am a little concerned with the fact that it's inconsistent and struggling at times sitting just overnight, or perhaps 3 or 4 days.
There's definitely some battery management software polishing needed.

 

[Buyer2021]

Service Manual states that when troubleshooting a parasitic draw on a Powerboost, the tech is to shutdown the truck, lock doors, remove key Fob from area, and wait 75 minutes.

Draw should be 500ma (.5 Amp) or less.

That's interesting, the WSM for my non-Powerboost sets limits an order of magnitude lower (bold added by me) ....

414-01 Battery, Mounting and Cables ​

2022 F-150​

General Procedures ​

Procedure revision date: 11/16/2021​

Battery Drain Check​

​

NOTE: No factory-equipped vehicle should have more than a 25 mA (0.025 amp) – 50 mA (0.050) draw depending on the vehicle's accessories. Check for current drains on the battery in excess of 25 mA (0.025 amp) – 50 mA (0.050) with all the electrical accessories off and the vehicle at rest for at least 75 minutes (depending on region). ​

 

[Jbcaindo]

I don't drive my powerboost for many weeks at a time. No tender, no issues.

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