Proper jump starting

[popo_patty]

Are the portable jump boxes safe to use on the Bronco? What is the proper connections? Positive and negative terminals, or use the ground on the fender? What is the sensor on top of the negative terminal? Is that the BMS? I just dont want to fry something.

soooo, can the guy use a jump box to jump his bronco by connecting to the battery terminals? Lol.
Or does he need a electrical engineering degree first?

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[Brian_B]

soooo, can the guy use a jump box to jump his bronco by connecting to the battery terminals? Lol.
Or does he need a electrical engineering degree first?

PhD

 

[Rydfree]

soooo, can the guy use a jump box to jump his bronco by connecting to the battery terminals? Lol.
Or does he need a electrical engineering degree first?

According to B6G you also should have a degree in fluid dynamics.
My wife likes more voltage thru the shower head while I prefer more amps.

 

[popo_patty]

According to B6G you also should have a degree in fluid dynamics.
My wife likes more voltage thru the shower head while I prefer more amps.

Well then. Per my knowledge of fluid dynamics and assuming electricity is like water based on comments above. If I’m flowing X amount of electricity through a large wire. If I drop the gauge of wire down (smaller), the electricity should speed up and I get better performance!
So to jump a battery faster, I should use the smallest possible wire to flow electricity faster

 

[Rydfree]

Well then. Per my knowledge of fluid dynamics and assuming electricity is like water based on comments above. If I’m flowing X amount of electricity through a large wire. If I drop the gauge of wire down (smaller), the electricity should speed up and I get better performance!
So to jump a battery faster, I should use the smallest possible wire to flow electricity faster

You must consider what happens when you divert a large river down a small creek

 

[Severum17]

soooo, can the guy use a jump box to jump his bronco by connecting to the battery terminals? Lol.
Or does he need a electrical engineering degree first?

Well, as the original poster, I think I have that figured out, I will though be standing BELOW the shower head.

 

[broncobase1]

I know it is best to attach to the negative side outside the BMS for charging but why would that be important for jump starting?

The only reason for doing this is to prevent sparks from blowing up the battery. Charging batteries give off hydrogen. Its rare but has been known to happen.

 

[jrollo7]

I stand corrected...carry on

Always follow Ducati!

 

[Sparkie]

Well, as the original poster, I think I have that figured out, I will though be standing BELOW the shower head.

I know I'm late getting these "volt meter to battery" photos uploaded to the Forum, but it's been a busy time.

When jump starting a dead battery Bronco from a portable 'jump box" or another running vehicle, it does not matter where you connect the jumper cables. You can use to the battery post, the bolt above the BMS, or the ground bolt on the fender. However, I believe it is safest to use the ground bolt on the fender.

The photos below show my meter's voltage at all 3 locations. They are all the same because of the linear circuit laws described in previous posts. The photos show the voltage while my Bronco was not running. When the Bronco is running and the alternator is active, the voltage was 13.87 at all locations. Unfortunately I could not get a photo because the engine vibration kept moving the phone camera while I held the probe in place.

With respect to the "water analogy" used in some comments, this is "just barely true" for simple DC linear circuits like our car batteries, but I don't recommend continuing those ideas on AC circuits, complex and/or electromagnetic circuits, digital electronics, and high frequency circuits.

First is the voltage at battery negative terminal:

Second is voltage just above the BMS:

Third is voltage at the fender's negative ground bolt:

 

[crenca]

When jump starting a dead battery Bronco from a portable 'jump box" or another running vehicle, it does not matter where you connect the jumper cables. You can use to the battery post, the bolt above the BMS, or the ground bolt on the fender. However, I believe it is safest to use the ground bolt on the fender.

The photos below show my meter's voltage at all 3 locations. They are all the same because of the linear circuit laws described in previous posts. The photos show the voltage while my Bronco was not running. When the Bronco is running and the alternator is active, the voltage was 13.87 at all locations....

I do not believe anyone was disputing what you 'can' do, rather what you 'should' do given that the BMS has a job to do and bypassing it in certain circumstances (e.g. trickle/maintaining) has consequences (not allowing it to do its job, which then directly effects how the battery is managed and thus battery life, what the Bronco thinks the SOC is vs. what it really is, etc.).

Without going back through the whole thread, I think most everyone agreed that in a dead battery situation and thus jumping, bypassing the BMS did not matter, but when putting a maintaining charge into the battery you did not normally what to bypass it.

The whole water analogy was just an effort to get some folks to understand that you could indeed bypass the BMS depending upon where you clamped (some insisted it could not be bypassed because of their erroneous understanding of the nature of electricity)...

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