Ron Pope Motorsports                California Custom Roadsters               

Electric fan

I think what PG was suggesting, was that sometimes using a connection to the frame for a ground can be less than totally reliable, and that rathe
ORF...wassa home run ground?


When you run a dedicated wire back to the negative battery terminal for the ground.

Some sensitive electronics, like some computer / fuel injection systems, can be glitch without a homerun ground
 
A picture is worth...two in the bush? I forget, but it's something important.
UlLX9SSAlMaqlpN7Cji1CGOO4UMr6n9v7mYlkNtXZUJGUfB4C7sb72VLzHFxurQGtHRpTOg_74Uy13FY2ja1ujGU1lZ0XPMWdi2bgvaKNLpTAUsYMiMnzK1NVE-PA87oLa6OdG9i-54ypHpEW-futr1wpRd6Dvsrvm_epLpQn5qJfywjLIBBb9UQ2gDYzj3IzcHpIanFTnGh1mQXSI1z_OUIzEs_wth8mij29UJk5oEExjjJNUPzjb1XifRW4fJiBMfPJuR5CHDU1k4nf_iAGTy5cV1PfpF2LpwaHolyKxhAO9FproO6RQi-TWuen6aBRTFhG9VZ1BDESkB_MN0bgZaPkRdk2B5Xn4F-daWiATEp02Y8Y5dUv-U6B0EuFacDD0MCLkyImh7C-TqT5-4ZwoZu3_I2Bg5Y356qWQQuLQ3bx5yl0WXRfIGzvGLEPM_3B5BQxgKXgoDNeq4ncUETi2KSt6A0r11qfF6iv4THmp_XyB4r9VVg3b2Xa-FE3xEyVUhPfyR8hHTDFor5zsJ1Hpk3UrkH8tUoD3QejpiG3z4FO6GJBEHMOH4hYQ5MNP43RLaly-TgF4YYCEfBL38XJ9GiFpf1EV6OMMOKlATI1FabIrvTrMvq-DWNZrjFdaBpeGLAA9GBdNNcJzpaeGJdVKJyNQjdLW3yWkzF0aBtudJyU7WmoMp6HCxoSm4fwa8Z6rp2FCZgR8OFvr5-L-omgKCh=w529-h352-no

Note how, in this typical grounding scheme, the circuitous path from the battery to any load, such as lights, fans, etc. Multiple cables and possible failure points (loose, corroded, resistive); lots of places for trouble. And, as IG notes, snooty modern electronics like EFI, fan controllers, remote controls (I have them all) don't even like to share grounds with others. I run a dedicated ground wire from every load back to a ground bus connected to the battery. Guarantees full and clean voltage to each load. It's saved my sanity many times.
 
Hey PotvinGuy,

I've heard of Ground Loops causing problems. Does that in anyway relate to our subject??? Can you explain?
 
Ground loops can be a problem in computer and audio systems. It's when two or more units that are supposed to be at same ground...aren't. If there are multiple paths for grounding, which can have different resistances and multiple signals traveling on them, currents can form or "loop." These currents can be just an annoyance, like hum in my old audio systems with lots of boxes and long cables, or they can cause errors in digital comm, or in worst case can damage equipment or burn down the house.
Fortunately, we shouldn't have such problems in our buckets. Our grounds are short and the typical loads (lights, fans, etc) aren't picky. Possible exceptions are electronics (EFI, fancy ignitions, anything digital), which should be grounded only at one point, preferably at a ground bus tied to the battery.
Check here for some light reading: Ground loop (electricity) - Wikipedia
 
If you have just one piece of sensitive equipment, can you run a ground back to the
battery for that one piece and be good.

Thanks for the explanation!
 
I have a GPS speedometer, maybe I should go back and fix the ground on it.

What I was thinking about when I asked the question above was for my data acquisition
device, the AQ-1 from AEM.
 
If you have just one piece of sensitive equipment, can you run a ground back to the
battery for that one piece and be good.

Thanks for the explanation!
Yes, that should be OK. SEMA folks haven't quite got the hang of modern electronics yet. It's odd, they are selling EFI and other sensitive products, but don't always plan for the noisy electrical environment of a car. A fan coming on will generate a big spike of RF noise. My EFI would reset when that happened until I got a soft-start fan controller.
There are tricks to minimize ground and power problems. I think I'll do a white paper on the topic and put it in the technical article forum.
 
Cool, thanks again ! :geek:
 

     Ron Pope Motorsports                Advertise with Us!     
Back
Top