Battery cables gone bad

[bmnelsc]

Just reporting my experience with a failing alternator. After changing the alternator for rebuilt and getting better charging - it was still low output once the car was well warmed up. Cables tested OK (cold) for voltage drop and continuity but once run for a while the positive cable would be VERY hot. Inspection showed a slight green smutz on the cable but not so much that a probe wouldn't find good connections for testing. The insulation was tight and smooth - no indication of damage or bulging from corrosion.

Replaced the cables which Porsche only sells as a unit (positive and negative cables running through the required grommets, etc) and the necessary posts for the four extra cables the S2 has bolted to the plus connection. The extra ground wire is now integrated with the neg post rather than a bolt on affair as previously. Now it shows the same level of charge even when hot AND it cranks over noticeably faster when starting - especially on a warm engine.

 

[scam75]

A functioning alternator cooling duct will also help.

 

[bmnelsc]

A functioning alternator cooling duct will also help.

Got that...
I also notice that the new cable appears longer than the original in that the "loop" it makes when it comes out the grommet (seemed to be fixed in position - e.g. the grommet doesn't slide on the cable) and turns to run along the firewall leaves it protruding a fair ways into the engine compartment so the cable still gets hot as the exhaust manifold is below that location. I think the only solution is to drive fast to maintain air flow
Seriously tho - I would think a heat shield of some sort would help here as there are several cables that run along the firewall behind the engine - all exposed to extra heat.

 

[scam75]

Yes heat plays a big part in sucking performance from the alternator. I've recently recomissioned my cooling duct and the alternator performs better. Was utterly ridiculous to get it back on in situ. A real game of twister!

 

[Frenchy]

Sorted the ducting to my alternator whilst the wheel arch liner was out, you can still buy the ducting from Opc, not silly money either, mine just needed new jubilee clips.