924Board.org

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Having cleaned and greased all my grounds as suggested by the forum,

Having had to get the haynes wiring diagram (page 306 - 1981 on) enlarged as l must be going blind, now sitting with A3 versions

I was going to run a bypass from the alternator to the battery to check the results, before getting under the vehicle. my local motor shop feels that the 10mm specified on my drawing is incorrect.

I note other diagrams on the forum show 2 x 2.5 leaving B+

They have offered 27amp cable max load 325 watts, do you think this is okay? l am happy to seek out 10mm cable if it is the recommended size.

George
Glasgow

1983 924

"A mind once stretched by a new ideal
never regains its original dimensions"

Smoothie · Posted: Sat Oct 09, 2004 5:09 am Post subject:

Yeah 10mm would be a beefy cable. I measure mine at 5mm (the '81-up single wire arrangement). "The bigger the better", but 10mm is going overboard.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

The OEM is not 10mm, I don't think. The 5mm sounds about right.

FWIW, when you are merrily motoring down the road ALL electrical power flows from the alt B+ to the loads (and NOT from the battery terminal). So, for instance you can think of everything that runs during a night time drive, add it all up, and that is how much (amperes) the cable needs to carry. The alternator rating presumably is related to the required maximum load so that number also gives a reasonable requirement.
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Cheers Smoothie,

I am going to run the bypass cable in the morning, if it clears up my non charging problem, l can then get underneath and check the cable between the alternator and the starter and then if required starter to battery..

Cheers for your input,

Ge

rge
Glasgow, Scotland
_________________
1983 - 924.......

"A mind once stretched by a new ideal will never regain its original dimensions".

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

Paul · Posted: Sat Oct 09, 2004 10:01 am Post subject:

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Morning world,

Yesterday the sun shone, this morning the car is covered in ice,

Checked alternator rating from purchase invoice history, it says 75amps,
which reading the above makes me doubt my 27 amp cables suitability, if cable is measured width ways it is 4mm.

Especially considering the cables l am bypassing between the alternator, starter (10 red) starter and battery (16 black) are the suspect cables.
go off.

My faintly glowing red light alt, has over the 14 days moved to glowing bright, l have had the battery out once and disconnected the black 16 positive lead which is on my suspect list anyway, didnt notice any crinkling, however wasnt looking for it.

Battery checked by autoshop yesterday not receiving a charge.

Onwards and upwards.

Ge

rge
Glasgow
Scotland
_________________
1983 - 924.......

"A mind once stretched by a new ideal will never regain its original dimensions".

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Morning World 2,

Connected my cable from B+ alternator to battery + , climbed inside car and the alternator/battery light was on ???

I never expected that....

Any thoughts on this .........?

George
Glasgow
Scotland
_________________
1983 - 924.......

"A mind once stretched by a new ideal will never regain its original dimensions".

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

B+ goes to the starter 30

Smoothie · Posted: Sun Oct 10, 2004 12:35 am Post subject: Re: Alternator B+

Joes924Racer · Posted: Sun Oct 10, 2004 12:39 am Post subject:

So it seems maybe a bad alt or maybe a connection to the alt.
Seems maybe you said battery not recieving a charge.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

I had the same problem until I wired the whole deal back from the plastic 3 wire hookup in front of the battery.I was 2 fried wires that were touching inside the firesleeve that I could not see.
_________________
1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Hi guys

just got back in,

Re attached cable to alt B+ and ran direct to battery +, alternator light in car comes on with no key in ignition??

Will recheck output on alternator at B+ it was good last time l checked.

And recheck other cable, ?

George
Glasgow
Scotland
_________________
1983 - 924.......

"A mind once stretched by a new ideal will never regain its original dimensions".

changeworks · Joined: 25 Mar 2004 Posts: 22 Location: Scotland

Just a thought,

I had connected the bypass cable on top of the exisiting B+ to starter, l dont know if that would be the culprit?

I am going to recheck the situation..

George
Glasgow
Scotland
_________________
1983 - 924.......

"A mind once stretched by a new ideal will never regain its original dimensions".

Smoothie · Posted: Sun Oct 10, 2004 2:09 am Post subject:

Yeah, if my brain's working right here.. Try disconnecting the existing wires that are on B+ and run your test cable from B+ to Batt+. If I'm not mistakin', that'll narrow it down to either a cable or alternator problem. (If you still get the light with it hooked up this way, something's fried inside the alt., otherwise it's a cable problem.)

Then if you find it's an alternator problem, still verify with an ohmmeter that the cable's good. (Check for shorts between wires - especially any that run trough the same sheathing.) Bad cables might wreck a good alternator.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox