In a video posted by a manufacturer

[jean genibrel]

In a video posted by a manufacturer of automotive aftermarket electronics, the presenter claims that the EFI unit should be run directly off the battery, not from a common power source. His logic is that if the other electronics and electrical accessories like fans, solenoids, etc draw too much current the EFi will not function properly. That's obvious, but would running the EFI system like the presenter in the video directly from the battery solve this problem?
He also says that if the EFI is in the trunk to run the negative wire back to the front of the car to the battery (if the battery is still in the front of the car. This would double the resistance and reduce the voltage accordingly.
See:

https://www.youtube.com/watch?v=uomAK8FIPuQ

Starting about 7:00

 

[3DDave]

Contacting the presenter is the first step.

How do you think the current is returned to the battery and what resistance does it have?
Where did the video get posted?
What is the company name?
Maybe it is a problem for that EFI unit and not any other unit, so what is the model of the unit?

 

[jean genibrel]

Contacting the presenter is the first step.
He is not available.

How do you think the current is returned to the battery and what resistance does it have?
I don't know. You mean the resistance in the cable?

Where did the video get posted?

https://www.youtube.com/watch?v=uomAK8FIPuQ

See at about 7:00 minute

What is the company name?
Maybe it is a problem for that EFI unit and not any other unit, so what is the model of the unit?
Holley. It is not a problem. He is simply showing do's and dont's.

 

[TugboatEng]

They tell you this so they can void your warranty more easily if you don't do the install correctly. If your wiring is sized correctly, you can make the connection wherever you want. When I install auxiliary engine packages on my boats I hook up the main power to the alternator output as it has a direct shot to the main battery lead and is sufficiently sized to handle all loads. It really cleans up the install vs. running a bunch of cables back and forth to the battery where they're exposed to corrosion and mechanical damage from regular battery replacement.

 

[3DDave]

Right in the comments - who to contact with questions.

Don S
3 years ago (edited)
First of all, FANTASTIC video. This is very well delivered with great info, exactly what I was chasing. Question. At 16:11 for example, how do you know what governs needing a dedicated battery feed (like the ECU as mentioned) or jumping power from the distribution stud? Because when you think about a modified car, I'd bet nearly every accessory demands its own battery feed. Cooling fans, fuel pumps, MSD ignition module etc. Along with ECU, starter, alternator.
Where's the cut-off point for what can go to the stud, and what HAS to go to the battery? Seems pointless having a stud in that case.


JEGS Performance
3 years ago
Don, great questions. For the answer, would you please call us at 1-800-345-4545 and speak to a tech or ask a tech at

http://www.jegs.com/AskATech

? Otherwise, you can call Holley direct at 270-781-9741

Still in business.

 

[TugboatEng]

Exactly correct, stacking more than two ring terminals on a single stud becomes problematic as the crimp portions will start to interfere with each other. A bus bar or distribution panel is the best choice.

 

[3DDave]

That video makes me sad. Instead of a distribution point, which they say is bad, they use the battery terminals as the distribution point, which is still a distribution point. Instead of a dry-erase picture they could have hooked an oscilloscope to the various points to show the difference. I expect there aren't any, but the Holley rep can certainly make a note to do a video about it.

Holley should know how to provide filtering on the electrical power inputs - it's a solved problem.

For example - this company makes such protection devices and mentions that AT THE BATTERY the voltage can reach 120V.

https://www.analog.com/media/en/tec...hnical-articles/P385_EN-Surge_Suppression.pdf

 

[jean genibrel]

So I think we all three agree that whether you connect the ECU or EFI directly to the battery, or you connect the accessories to the same battery, or you connect the accessories and the ECU/EFI to the battery, or the connection block the battery will be called upon to deliver the same amount of current. (If you use the correct gauge wire).

 

[jean genibrel]

PS: Do you believe that insufficient voltage can cause an ECU, EFI, or fuel pump to fail?

For example - this company makes such protection devices and mentions that AT THE BATTERY the voltage can reach 120V.

https://www.analog.com/media/en/technical-document...

Thanks for that document. The voltage spike reminded me of the old days with point ignition when an engine was hard to start we would turn the headlights on and off rapidly. I knew what that did but I did not think that the voltage could reach 120.