Proper jump starting

[crenca]

I didn’t say that….BMS tab is on battery post side then to the sensor then outgoing wires. If tab was on wire side coming out of BMS then yes it would make sense. I’m not trying to argue with anybody on here I’m just not seeing BMS between tab and battery post. Post and tab are both on same side of BMS

Well now I’m not exactly sure what you’re looking at. It’s battery post (granted a little extension), BMS (black plastic box) sitting on top of said little extension, and then on top of BMS the tab and the rest of the Bronco.

For the BMS to measure current has to flow through it…

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[Ducati1098]

BMS tab is on battery post side

 

[MadMan4BamaNATL]

That is NOCO anti-corrosion coating, as previously stated - basically a fluid film version of dielectric grease that gives better coverage as it seeps into cracks where dielectric grease would miss. If I clean that off then they will be more susceptible to corrosion. I have battery terminal brushes lol. I periodically use them to clean my battery posts and terminals and then re-coat with battery terminal protectant.

Ahh, missed that comment you made about it. Thought it looked like some strange corrosion.

Was thinking like, "how in the world did it battery get so dirty?" Think I"ll look into some of it myself, then folks can think my battery is dirty too! Under my hood is just very dusty. It's a Winter chore that I'll wipe it all down under there; my twin compressor especially.

 

[Nibroc99]

Ahh, missed that comment you made about it. Thought it looked like some strange corrosion.

Was thinking like, "how in the world did it battery get so dirty?" Think I"ll look into some of it myself, then folks can think my battery is dirty too! Under my hood is just very dusty. It's a Winter chore that I'll wipe it all down under there; my twin compressor especially.

Yeah cleaning it off and reapplying occasionally is absolutely good practice because of all the dust and debris that sticks to it! I also spray other bolts and connections with it that could be prone to rust or corrosion, and it works a charm. Looking forward to being able to undercoat my vehicle soon with some fluid film that's similar to this stuff. Sure it's a mess to work on, but I am always the one doing the work and know what I'm getting into. Usually I'll use a degreaser to take oil off of the parts I'll be working on and then reapply when I'm done. It's a fun process. I digress

 

[crenca]

Sure it's a mess to work on, but I am always the one doing the work and know what I'm getting into. Usually I'll use a degreaser to take oil off of the parts I'll be working on and then reapply when I'm done. It's a fun process…

I live in the dry southwest where fluid film is unnecessary, but I wondered about this, would it dissuade me from oil changes and what not… I guess it just adds an extra step.

 

[Nibroc99]

I live in the dry southwest where fluid film is unnecessary, but I wondered about this, would it dissuade me from oil changes and what not… I guess it just adds an extra step.

The oil pan is plastic, so there shouldn't be any of that stuff on your oil change parts anyway - at least speaking about the 2.7L.

 

[crenca]

The oil pan is plastic, so there shouldn't be any of that stuff on your oil change parts anyway - at least speaking about the 2.7L.

2.3 here, so it’s at least genuine tin

 

[Sparkie]

Yes, while I agree the tab is NOT physically on the battery post side, I don't believe it matters for the negative ground connection -- unless someone at Ford poorly designed the BMS circuitry, but then these parts would be failing within hours of leaving the assembly line.

If there is an electrician or electrical engineer (I am a chemical engineer), please post some clarification so this thread can go to bed.

 

[crenca]

Yes, while I agree the tab is NOT physically on the battery post side, I don't believe it matters for the negative ground connection

Your correct, you get a negative ground connection whether you connect directly to the battery post, to the tab itself, or to a grounded metal part beyond the tab (i.e. the rest of the Bronco).

It matters however if/when you want the BMS to "see" (i.e. measure by having the current pass through it) the charging. By connecting to the battery post itself, the BMS can not "see" the current because it is not passing through it for it to measure.

For proper battery life and the use of the BMS as it was designed, you want the the BMS to "see" the current in almost every case - the exception perhaps being when you are jumping an essentially dead battery, but you certainly want the BMS to see the current when you are trickle/maintain charging...

 

[Nibroc99]

Yes, while I agree the tab is NOT physically on the battery post side, I don't believe it matters for the negative ground connection -- unless someone at Ford poorly designed the BMS circuitry, but then these parts would be failing within hours of leaving the assembly line.

If there is an electrician or electrical engineer (I am a chemical engineer), please post some clarification so this thread can go to bed.

It's common knowledge in electronics that in order to measure amperage, the circuit must be interrupted by the measuring device. However, specifically why it has to be measured this way is not common knowledge. Here's a snippet from an article on the electricity forum exploaining it.

So, since the BMS is essentially a voltimeter and ammeter that automatically sends info to the Bronco's computers, it must be connected in series between the load and the power source (in this case between the negative power terminal and the load) in order to tell the computers how much load there is on the charging system.
I'm no scientist either though so this is largely speculative, but that is the general idea of why it's important for the load to be in series after the BMS.

 

[Sparkie]

Your correct, you get a negative ground connection whether you connect directly to the battery post, to the tab itself, or to a grounded metal part beyond the tab (i.e. the rest of the Bronco).

It matters however if/when you want the BMS to "see" (i.e. measure by having the current pass through it) the charging. By connecting to the battery post itself, the BMS can not "see" the current because it is not passing through it for it to measure.

For proper battery life and the use of the BMS as it was designed, you want the the BMS to "see" the current in almost every case - the exception perhaps being when you are jumping an essentially dead battery, but you certainly want the BMS to see the current when you are trickle/maintain charging...

As I said earlier, I'm not an electrician.
From a physical cable connection, I almost always connect to "ground" away from the battery, and it does start the car I'm jumping.

However, if the "-" cable is connected to the battery post, wouldn't the circuit still "complete" through out the Bronco?
I would like an electrician to briefly explain why the BMS is by-passed with a "different" ground connection.

 

[crenca]

However, if the "-" cable is connected to the battery post, wouldn't the circuit still "complete" through out the Bronco?

Nope. Electricity flows through the shortest, least resistent path, avoiding longer/harder ones (like water). The entire Bronco is a long, more resistant path. Thus the (well, vast majority) of the current only passes through the battery itself since you have connected directly to the posts.

That's why the BMS does not "see" the current.

 

[Sparkie]

It's common knowledge in electronics that in order to measure amperage, the circuit must be
.......
I'm no scientist either though so this is largely speculative, but that is the general idea of why it's important for the load to be in series after the BMS.

Yes, I have used amp meters - the old Radio Shack analog meters with a mirrored needle display and the new digital ones.
My point is the meter is between the "hot positive" and the "negative ground" so I don't think the physical "-" cable location matters.

 

[Sparkie]

Nope. Electricity flows through the shortest, least resistent path, avoiding longer/harder ones (like water). The entire Bronco is a long, more resistant path. Thus the (well, vast majority) of the current only passes through the battery itself since you have connected directly to the posts.

That's why the BMS does not "see" the current.

How is NOT possible to "see" current when the BMS shares the same common negative ground with the rest of the Bronco?
Please let me know.

 

[crenca]

How is NOT possible to "see" current when the BMS shares the same common negative ground with the rest of the Bronco?
Please let me know.

Gosh, physics...Maxwell's equations, classical electromagnetism, etc. might be a place for you to start.

Think of it like water (at least water in a gravity field). If electricity is a river, amps is the measure of the width/depth of the river, its volume. Volts is the measure of its speed, pressure. Resistance is the path it takes and the things that direct it, block it, and route it.

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