Upgrading Grounding Cables...

[Jaak]

maybe we should make sure that the + terminal under the hood is as secure as possible to keep that type of short from happening. it's just as likely to happen in regular cars where the battery is up front though. any time you have a decent system installed, those power cables up front get upgraded, eliminating the 'fusible link' effect.

Actually I'm talking about the impact from an accident doing this, not the wire falling off. It's unlikely to happen and one could even speculate that if it did happen, the car would be a write off at that stage anyway.

Sorry I'm late to this thread. The HyperGround How-to in the knowledgebase describes this also. For electrical flow its also better to use large gauge (0-2 gauge) power audio cable with fine strand wire since volts flow over the surface of wire not through it like amps. Here's the link:

Hyperground - How-to

LOL, that's true at RF frequencies, not for power in your car. There's a few companies that take truths, twist them in to marketing and they're no longer truths, but it sells product. You don't need very fine stranded power cable, especially in an environment where the cable will be installed and not moved constantly.

[richierevs]

Actually I'm talking about the impact from an accident doing this, not the wire falling off. It's unlikely to happen and one could even speculate that if it did happen, the car would be a write off at that stage anyway.



LOL, that's true at RF frequencies, not for power in your car. There's a few companies that take truths, twist them in to marketing and they're no longer truths, but it sells product. You don't need very fine stranded power cable, especially in an environment where the cable will be installed and not moved constantly.

Ok, I'll agree to disagree and leave it at that.

[gooeytek]

Actually I'm talking about the impact from an accident doing this, not the wire falling off. It's unlikely to happen and one could even speculate that if it did happen, the car would be a write off at that stage anyway.

By "secure" i meant that there should be a means in place where that + terminal won't be able to contact the sheetmetal in the case of an impact, as in the sheetmetal getting distorted to the point of contact. Granted, the right amount of force & the right point of impact will always be the exception, but that holds true with everything. Maybe an impact sensor/g-threshold meter that trips a breaker right at the battery.

[Jaak]

Ok, I'll agree to disagree and leave it at that.

That's cool, and I understand where you're coming from. Examples of my employers you can find at www.agilent.com and www.tektronix.com I know how this stuff works and how to actually measure it in detail.

Skin effect does have an impact at RF frequencies but for this application it is not a contributing factor to losses in the wiring.

Google RF Skin Effect to learn more. Here's one example for you:

http://www.answers.com/topic/skin-effect

For a DC supply with low frequency fluctuations, the skin effect penetrates the entire copper wiring of our cars and a higher conductor count has zero benefit. In fact, in an ideal situation a solid bus bar would be more desirable for this application, except routing and insulation is a PITA. Even frequency transient response of the system for our use is not an issue. The biggest problem is I2R losses and that's a combination of wire gauge and distance. Which is why the long +ve wire is heavier than the short grounds.

[Jaak]

By "secure" i meant that there should be a means in place where that + terminal won't be able to contact the sheetmetal in the case of an impact, as in the sheetmetal getting distorted to the point of contact. Granted, the right amount of force & the right point of impact will always be the exception, but that holds true with everything. Maybe an impact sensor/g-threshold meter that trips a breaker right at the battery.

Ah, gotcha...

Statistically, I wouldn't worry about it.

The chances that it'll be an issue.... Eh, not so high!

[richierevs]

That's cool, and I understand where you're coming from. Examples of my employers you can find at www.agilent.com and www.tektronix.com I know how this stuff works and how to actually measure it in detail.

Skin effect does have an impact at RF frequencies but for this application it is not a contributing factor to losses in the wiring.

Google RF Skin Effect to learn more. Here's one example for you:

http://www.answers.com/topic/skin-effect

For a DC supply with low frequency fluctuations, the skin effect penetrates the entire copper wiring of our cars and a higher conductor count has zero benefit. In fact, in an ideal situation a solid bus bar would be more desirable for this application, except routing and insulation is a PITA. Even frequency transient response of the system for our use is not an issue. The biggest problem is I2R losses and that's a combination of wire gauge and distance. Which is why the long +ve wire is heavier than the short grounds.

^^^Good detail. I use the thin stranded cable to ground the engine heads to improve the consistency of the spark and low-end throttle response. Empirically, it has made a difference although I've not spent the time/effort/$$$$ proving it on a dyno. I noticed it especially when I had my last tune adjusted so the throttle position sensor (TPS) output and the peddle position sensor (PPS) output were set to a 1:1 ratio to simulate a an old school throttle cable. At least, this has been my experience.

[ginuwine]

does this stop dimming when sub hits? my dash lights dim like crazy when bass hits any idea had cap mad no difference with or with out it put a 4Ga ground on batter in trunk now any other ideas?