Ford BMS Battery Monitoring System: How it Works and How to Properly Charge Your Battery!

[p3zz]

Found this video explains the BMS system.

Rick et all, I see folks talking here and in the Youtube video description mentioning Forscan; I have the latest version but I can't find the screen shown here -- any idea how to enable it? Thanks!

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[AzScorpion]

Rick et all, I see folks talking here and in the Youtube video description mentioning Forscan; I have the latest version but I can't find the screen shown here -- any idea how to enable it? Thanks!

Sorry I don't use Forscan. You could link this page and post it over in the Forscan thread. There's many there who will most likely know where to find it.

These are the 2 most popular ones:

https://www.ranger5g.com/forum/threads/forscan-crowdsourced-wiki.2008/

https://www.ranger5g.com/forum/threads/forscan-modifications.1844/page-73#post-494106

 

[got3fords]

Not sure what options are available for the Ranger, but when my last motorcycle battery died, I replaced it with a Lithium Ion one. It's about a third the weight and half the size. It was pretty expensive though. Since my bike sits a lot I figured it would be worth it. It has a built-in feature that if it dies, you press a button on top to get several more cranks out it. Came in really handy once.

 

[SemperVee]

Started a thread like this years ago and now have same issue with my seldom driven 22 F150 V8 voltage.
I have always questioned the validity of the BMS and keeping the battery voltage to 12.2 or lower!!

 

[Dr3wDrop]

Good video Dave. I didn’t realize that Forscan had this feature. My Ctek charger is with remote hookup is on the frame and positive terminal. Might change the ground location on the negative side as shown here. Just make for a more efficient system.

As a note to others on here. Our factory settings in the BCM have the charge capacity set to 70% of total capacity from factory. Probably done to give longevity to the battery. The negative side of that is at full charge less than 75% of capacity is available. I changed mine to 90% not long after I got the truck almost 2 years ago. Doesn’t seem to of had a negative effect on the battery doing that.

thanks for your aid in figuring out how to increase the battery charge capacity. Mine out the gate was set at 75% and I upped it to 90%

 

[Michel Jeanneau]

So glad I deleted my ASS with FORSCAN, probably why despite 3 years of short commutes (3 miles one way), I've had zero issues with my battery or its state of charge

 

[P-38Ranger]

This is a good thread, but it kind of mixes the battery management system knowledge with just not driving enough.
I had an 1997 F350 that I wanted to keep for my 15-year-old son for a year and I went and bought a cheap harbor freight charger and kept it on that and there was no problem.

When my mother moved into an apartment and then six months later, we realize she shouldn't be driving anymore but her husband still needed access to the van. I put a battery disconnect on the 2005 Honda odyssey because it would drain the battery in two weeks and no AC power was available.

If you don't drive any vehicle regularly, you have a choice, disconnect or a trickle charger.

Pretty simple.

This is even more true for EV's. They are not 5k miles a year vehicles!

 

[Dr3wDrop]

This is a good thread, but it kind of mixes the battery management system knowledge with just not driving enough.
I had an 1997 F350 that I wanted to keep for my 15-year-old son for a year and I went and bought a cheap harbor freight charger and kept it on that and there was no problem.

When my mother moved into an apartment and then six months later, we realize she shouldn't be driving anymore but her husband still needed access to the van. I put a battery disconnect on the 2005 Honda odyssey because it would drain the battery in two weeks and no AC power was available.

If you don't drive any vehicle regularly, you have a choice, disconnect or a trickle charger.

Pretty simple.

This is even more true for EV's. They are not 5k miles a year vehicles!

I whole heartedly agree with you. However, if I get low charged battery electrical gremlins for not driving for 3 days there is a problem.

 

[Bsthroop]

I whole heartedly agree with you. However, if I get low charged battery electrical gremlins for not driving for 3 days there is a problem.

Yes agreed, not driving a lot is made much worse by having the system only charge the battery to just barely above sleep mode voltage. Even if it is driven a hundred miles a day, the battery life will be shortened due to chronic under charge.

 

[SemperVee]

SO disconnect the BMS is the anwer? Disconnecting it will let it charge "naturally" as it has the past 100 years on the alternator or has the ECM capped that also? What does "ASS" mean in connecting to Forscan? I am a mac guy so I may have to get a cheapy windoze machine to use forscan..

 

[Wings06j]

Found this video explains the BMS system. It shows how you should jump start and charge it too. So many have never had this system (myself included) and there's always questions about what to do with these. Overall a good helpful video but the guy does get a little repetitive towards the end.

Yes, this probably qualifies for the longest thread title on here. ?

Is there a way to see charging / discharging in Forscan like what the video shows? Actually see Amps in/out, % charged and voltage? I just started using it and am curious how my little 2A charger is doing and where my battery is sitting after a week or two of my ultra-short distance driving.

 

[AzScorpion]

Is there a way to see charging / discharging in Forscan like what the video shows? Actually see Amps in/out, % charged and voltage? I just started using it and am curious how my little 2A charger is doing and where my battery is sitting after a week or two of my ultra-short distance driving.

Sorry I don't know as I don't use Forscan. Maybe Rick @Trigganometry knows and will chime in once he sees this. I use this maintainer here and at first it took a good 24hrs to fully charge. Now I use it regularly (2-3 days a week) and it'll charge within a few hours.

 

[Bsthroop]

Is there a way to see charging / discharging in Forscan like what the video shows? Actually see Amps in/out, % charged and voltage? I just started using it and am curious how my little 2A charger is doing and where my battery is sitting after a week or two of my ultra-short distance driving.

I don't believe that screen is available in Forscan but I could be wrong. I installed a volt meter so I can monitor voltage and see what works. You have to be quick because as soon as you get near the Ranger every light and system come alive and the voltage starts dropping. Before upping the SOC to 90% and using a trickle charger the voltage would be below 12v regularly. Now it stays in the high 12 range, all with a new battery.

 

[Trigganometry]

I have never come across that feature in Forscan. There are other app solutions for getting that type of data from your OBD connection. Dash commander comes to mind but there are others. Just load the PID codes and you get that data through your phone or a separate tablet.

 

[SemperVee]

I have watched this video several times and visited the dealer for a battery health check which tested very good. Thus I am using this charger and considering diconnecting the bms if problematic going forward. https://www.amazon.com/Automotive-M...x=6+amp+battery+charger,automotive,138&sr=1-4

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