Earthing kits - myths or truths? (modem size warning)

**takai** · 29-05-2006, 09:16 AM

I think that it is fairly well grounded, but needs a little bit of regulation at times.

**urantia** · 29-05-2006, 09:39 AM

stop bieng so negative you ppl.
On the positive side

i now understand why my coolant was giving me a voltage reading, i could even get a voltage reading from putting 1 of the probes on the rubber radiator hose!! *scratches head on that one*

Thanx for the explanation makes perfect sense now.

**kingmick** · 29-05-2006, 09:46 AM

must have been electrifying!

**urantia** · 29-05-2006, 11:52 AM

watt would explian me getting a voltage reading with 1 probe on the radiator rubber hose, and the other on the battery terminal?

(and yes i partly used this post to use the word "watt"

)

**kingmick** · 29-05-2006, 12:31 PM

its all newton to me. dint have your finger on the prob?

**oldcorollas** · 29-05-2006, 01:40 PM

Originally Posted by urantia

watt would explian me getting a voltage reading with 1 probe on the radiator rubber hose, and the other on the battery terminal?

(and yes i partly used this post to use the word "watt"

)

cos rubber is conductive

carbon black in the rubber allows it to conduct electricity.. if it was pure rubber (like a rubber band) it would not.

also partially why you don't get massive shocks every time you get out of the car... the rubber tyres will conduct a small amount of current to the road...

i think

try checking the resistance between two points maybe 1cm away from each other on said hose...

**urantia** · 29-05-2006, 01:42 PM

hehe!

didn't have a finger on the probe. Will do it again tonight just to make sure i'm not seeing things. CURRENTly i'm at work and unable to test.

**urantia** · 29-05-2006, 01:43 PM

I see you snuck one in there while i was replying oldcorolla's

Right well then that would explain it! I never knew that!! very interesting!~

**oldcorollas** · 29-05-2006, 01:47 PM

sorry, wasn't trying to insulate the flow of spiked humour

**Mos** · 29-05-2006, 07:00 PM

Originally Posted by oldcorollas

cos rubber is conductive

try checking the resistance between two points maybe 1cm away from each other on said hose...

Hmm I dunno

.. With a Fluke 87III the top radiator hose is open circuit, ie greater than 40Mohm.

Tomorrow, I'll check it with the insulation resistance tester (up to 400Mohm).

Apparently as they age they lose some of their insulating properties, but I don't know how long for how much...

Mos.

**oldcorollas** · 29-05-2006, 10:57 PM

i should have said.. rubber has the potential to be conductive

not always, but for you to get a reading between rubber and battery, it must be conducting

it may also depend on the voltage... i know i've zapped myself dozens of times between spark plug and radiator hose.... always lean on it to steady cos i think it will help... then... ZAP...

got a few different pipes to try?

ed · 29-05-2006, 11:00 PM

ok, does this need locking, or are the bad puns over?

**The Last Streetfighter** · 30-05-2006, 10:36 AM

Ed, you will regret your Reluctance to close it. Take your batt and ball and go ohm! That will coulomb down a bit. Reading all those damn puns nearly gave me the flux. But if I wasn't sitting in this super position, I would have missed out.

**urantia** · 30-05-2006, 11:16 AM

spose there's nothing else to be covered/discussed/bad puned

**o_man_ra23** · 31-05-2006, 01:38 PM

Yeah, i cant see a small ripple changing anything significant on the motor side of things, as stated the ECU should have its own regulated power supply. If the ripple starts getting large, you have a problem anyway and need to know about it. The noise in the amp theory is one that can be solved by buying high quality amps and head decks. The coustic amp and pioneer deck i run in the girlfriend's excel has zero engine noise. The kenwood deck in my RA40 with bodgy old engine wiring has zero engine noise. Neither system has a filter. My cheap old boss amp used to suffer terribly from engine noise till i put a filter in, but again, comes to buying quality items to put in your car.

Cheers, Owen

Originally Posted by Mos

Things like headlights, electric motors, heater elements, solenoids, etc wont care about that level of ripple.

Things like ECUs could be affected by this, if there is a threshold somewhere that gets affect by the change, but that's why if it's critical it will have its own internal power supply. An engine ECU has a reasonably good power supply with adequate filtering (but need to scope for academic reasons

).
All the engine sensors are run off 5V (VCC) and their own dedicated ground path (E2).

Injectors may be affected in that the 2V difference can change their opening time - to what practical extent? I have no idea... anyone?

One thing that could be affected is the stereo - if its power input filtering isn't up to the job it can carry through to the speakers. This particular noise is at around 30Hz and will increase in frequency with engine revs - so it will be perfectly audible.

Mos.