FYI...Battery Health

[Slimjimmn]

Glad I saw this thread. I am having the same issues. Battery charging 14.2v when running and 12.5v when the car is off.
I have noticed a smell in my garage for a month or so as well. Low and behold last night while swapping out my 004 for my stock DV and then today while finishing up my n249 delete and blockoff plate install, I noticed the smell again. Pretty ronchy. Well yea, its my f-en battery. Leaking acid like a mofo. Cheap ass Napa gold battery from the PO of the car.
symptoms:
rough cold starts for a min or so
high rpm misfires
sometimes boggy off idle

guess its time for a Quality interstate battery.

[gdoggmoney]

I cleaned up my alternator. Removed the voltage regulator, put ox guard on the copper to aluminum junctions, polished all the corrosion off surfaces and brushed the corrosion off the voltage regulator heat sinks. The alternator wire is still suspect and likely getting replaced tonight as it's original and there is enough corrosion at the battery end and I just don't like the factory ends. Much less in the way of lights dimming if you cruise and roll a couple windows down.

The jetta melted a fuse for the fan module a while ago, and now that you guys mention that I am going to pull that aprt tonight and go to town on it.

This is temporary, once the car gets an optima it is going in the trunk.

[groggory]

I cleaned up my alternator. Removed the voltage regulator, put ox guard on the copper to aluminum junctions, polished all the corrosion off surfaces and brushed the corrosion off the voltage regulator heat sinks. The alternator wire is still suspect and likely getting replaced tonight as it's original and there is enough corrosion at the battery end and I just don't like the factory ends. Much less in the way of lights dimming if you cruise and roll a couple windows down.

The jetta melted a fuse for the fan module a while ago, and now that you guys mention that I am going to pull that aprt tonight and go to town on it.

This is temporary, once the car gets an optima it is going in the trunk.

Could you post a link to the oxidation guard you're using?

[gdoggmoney]

Could you post a link to the oxidation guard you're using?

2k copper anti seize on heavy spots, and ox-guard brand zinc paste on aluminum. Ox guard specifically says it is for dissimilar metals and aluminum junctions.


Your voltage regulator has a nice copper u shaped connector that goes to aluminum with no corrosion guard, and another copper to aluminum junction. You'll see it all when you take it apart, bosch and dissimilar metals being used in key places, like peanut butter and jelly. Expect nothing less.


White fuzz/corrosion and black tarnish/corrosion. Break out the dremel, wire wheel attachment and 400 grit sandpaper.





This stuff is basically all colloidial copper.

[Slimjimmn]

why dont you use dielectric grease... I would never put copper paste on a metal to metal electrical connection.

[BassNotes]

Dielectric grease will fill the gaps between the contact surfaces and prevent oxidation, but its main virtue is that it's a high-voltage insulator (great for spark plug boots, for example). The stuff that gdoggmoney suggests should actually help make better conductivity between the conductor surfaces in addition to the protective qualities, but you would generally want to keep it off of non-conductive surfaces.

[gdoggmoney]

Dielectric grease will fill the gaps between the contact surfaces and prevent oxidation, but its main virtue is that it's a high-voltage insulator (great for spark plug boots, for example). The stuff that gdoggmoney suggests should actually help make better conductivity between the conductor surfaces in addition to the protective qualities, but you would generally want to keep it off of non-conductive surfaces.

Thanks. You said what I would have.


Your moving 100+amps through that cable, and through these dissimilar metals. increasing the surface area by using zinc impregnated grease or colloidial copper anti seize will actually do just that -- increase the surface area and promote a cooler connection.

Heat = resistance = voltage drop etc. etc. etc.

[Slimjimmn]

never had an issue with dielectric grease.
I put it on battery terminals, starter terminals, and alternator terminals when I disconnect them. Only thing is it heats up and evaporates so you have to re-apply it every year or so.

and if you are running 100+ amps through a starter b+ wire or alternator wire then you have some other problems!

Most alternators put out 20-40a with loads on.

[babarber]

vr6 alt is rated at 120 amps with a 150 amp fuse
1.8t alt is 90 amps with a 120 amp fuse

your going to see way more then 40 amps

if you have aftermarket radio and your driving with lights on etc im going to say you would see 60+ amps at times and even higher possible loads

[BassNotes]

Most 1.8T alternators I've seen are 120A (including mine).

Most of the time, of course, after the initial re-charging of the battery after a start, the current demand will be under 30 to 40A even with the headlights, fog lights, and a lot of accessories turned on.

I wouldn't waste dielectric grease on battery posts, alternator connections, etc. Sure, it will work, but for preventing oxidation and keeping moisture out between surfaces so will lithium grease at a fraction of the cost. I like gdoggmoney's suggestions for high-current connections, especially those whose quality can be problematic, but I've also used lithium grease in those situations to good protective effect, even if it doesn't enhance the conduction.

[Minho78]

vr6 alt is rated at 120 amps with a 150 amp fuse
1.8t alt is 90 amps with a 120 amp fuse

your going to see way more then 40 amps

if you have aftermarket radio and your driving with lights on etc im going to say you would see 60+ amps at times and even higher possible loads

2002 1.8t alternators are 120AMP.

[babarber]

my theory is they changed to 120 amp alternators at the same time they switched to wideband 02 sensors because my 01 wolfsburg has the 120amp but my dads 01 1.8t had 90amp orignally

i said 120 amp is the vr6 alternator is because alot of people know it that way and when you go to a parts store and ask for the vr6 alternator they know its the 120 amp

[Slimjimmn]

dude, if any of your alternators are pumping out 120A with loads on driving that thing would be smoking like a mofo in a couple minutes if it didnt start on fire or melt the cable.

Put an amp clamp on your alternator b+ wire when the car is idling with headlights , radio, and defrost on and I bet it will be 20-30 maybe 40amps. Maybe a little more if you have a big system, possible 60-70a (its why they have upgraded alternators 180a and require 6g or better wires).

Yea the alternator is rated at 120a but thats Full Fielding the alternator.
Put 30A through a battery charger and the cable ends get hot to the touch after 10min.

[groggory]

The ox guard appears to be non conductive.





However, I believe in its merits as an oxidation inhibitor.

I don't believe it will improve on the conductivity of bare metal to bare metal

I do believe it will NOT reduce conductivity

I do believe it will improve long term conductivity

[Slimjimmn]

another update on this.
I installed a new battery (interstate mt47) with new B+ cable to starter and also new neg terminal.

Holy smokes did it make a difference.
1-car starts better, duh
2-car does not run rough on cold starts
3-car actually has boost in first gear now (never had this really since I bought the car!!)
4-runs smoother at higher RPM for sure!
5-holds boost better now
6-dont get that random misfire ever once in a while when boosting hard in 3-4 gear. it was like a random misfire here or there like power dropped out.

My car is actually fun to drive again. I never would have thought a battery would make that much of a difference. I mean yea, it was 5yrs old, but it tested out good and never gave issues being dead. I even left a door open overnight last fall and it didnt kill the battery.

[babarber]

people take for granted how much a good clean and stable voltage matters to their car