Alternator not Charging?

[chadco]

Have read MANY forums already about this issue and have narrowed it down to the alternator light. The reading across the battery is a no show on the alternator until I jump the connection on the bulb housing and then the light goes out and the system starts charging correctly with the voltage across the battery reading a steady 13.8 volts. The alternator light is on when I turn on the key and it stays on while the car is running. I jump the connection and wallaa the light goes out and the system kicks in and charges perfectly. Any Ideas??

[porwolf]

That looks like the battery in your case actually is charged through your indicator light short instead from the regulator. Maybe something wrong with the regulator or the connection from the regulator to the battery.

[wwest]

Car year?

The below assumes a momentary "jump"....

The bulb filament resistance provides a "jump start" for/to the alternator each time you start the engine. Some cars use a resistor in parallel with the bulb in order to "UP" that initial jump current flow.

You may have the wrong bulb, filament resistance to high (LED?) in that position.

Since everything seems to operate properly once you (momentarily?) jump the bulb the only thing to suspect other than that would the VR "sinking" to much of the normal jump current.

[wwest]

"spring plates" = 1979 SC.. which came with the external VR, inexpensive purchase and easy DIY install/swap.

Late to the party/question, but if your A/C cools satisfactorily at a consistent roadspeed, north of 2500 RPM, as mine does/did, you can get additional cooling capability at idle by lifting the heat lever just ever so slightly. The cabin heater blower comes on, with virtually no cabin heating, and the engine IDLING airflow through the rear lid condenser increases substantively.

There are also a couple of DIY methods through which you can improve the level of additional airflow provided by the cabin heat blower, even automatically with a little extra effort and coin.

Trinary pressure switch to engage the cabin blower automatic or if you don't wish to open the A/C system "this":

Senasys -

[Discseven]

Originally Posted by wwest

"spring plates" = 1979 SC.. which came with the external VR, inexpensive purchase and easy DIY install/swap.

Late to the party/question, but if your A/C cools satisfactorily at a consistent roadspeed, north of 2500 RPM, as mine does/did, you can get additional cooling capability at idle by lifting the heat lever just ever so slightly. The cabin heater blower comes on, with virtually no cabin heating, and the engine IDLING airflow through the rear lid condenser increases substantively.

There are also a couple of DIY methods through which you can improve the level of additional airflow provided by the cabin heat blower, even automatically with a little extra effort and coin.

Trinary pressure switch to engage the cabin blower automatic or if you don't wish to open the A/C system "this":

Senasys -

Will... you must be doing bad drugs again.

[wwest]

WHY, thread hard to follow?

[rick-l]

Can you find a link to the tech bulletin for 73-83 911/T? I can't. It is about installing a new alternator with an internal regulator. It says you need to install a 91 ohm 5 watt resistor in parallel with the 2 Watt bulb. Does this apply in your case?

[wwest]

Wouldn't hurt to install the resistor regardless.

[Ronnie's.930]

Originally Posted by Discseven

Will... you must be doing bad drugs again.

"Again", Karl? With Mr. West and bad drugs, it's always!

[wwest]

Hey, there are no BAD drugs, just Tequila.

[chadco]

Thanks for all the replies guys! Yes it is a 1979 and I am going to try the resistor thing first. Yes it is just a momentary jump of the bulb that starts it up charging. I had an LED bulb in at first and thought that to be the problem. Switched it out to a factory bulb for that year and it would not light at all? So I am going to order a new bulb socket ( if possible) and the resistor as well and see what I can come up with. OH, yeah and my car is a euro spec car from across the pond and has a back dated heating system, so that A/C thing sounds COOL but won't work for me. I have a new Retro Air system I am dropping in, in a few weeks. I have been restoring the car every day for the last year and a half. Still have about 6 months to go. Found out doing the rebuild of the motor that it is a Max Morritz car from Germany. Pretty Cool:-)

[wwest]

LED bulb would definitely be a problem, not enough current flow to "kick start" the alternator.

DIY install of the LED bulb? In that case someone may have used an "off-the-shelf" LED which would have required an external resistor to limit LED current flow. If so, look for a thermo-fit "lump" in the wiring.

[JFairman]

Maybe not the same exact topic but this 160 amp alternator is GREAT!

Porsche 911 Alternator 1984 1989 High Amp 160 Amp High Output Generator | eBay

I got one last spring. It's totally rebuilt and it looks like a new Valeo with more internal wire windings and bigger guts in general. I don't feel it bogging down the motor or anything like that.

My 90 amp Valeo was only a few years old and working as good as it could but this thing charges a lot better. I sold the Valeo after installing this.

With my after market stereo with a big high power amp in the trunk and extra speakers along with a sub woofer playing loud with lots of Bass and the AC on full blast with two 10" fans, one on the 930 tail condenser and one on a Zims left rear fender condenser running, my VDO voltmeter gauge shows 13.5 volts charging at idle.
I'm convinced this is the best alternator you can put in a 911 or 930 if you need more than the stock one. It has a new high output voltage regulator on it.

[wwest]

13.5 volts is to close to the battery "float" voltage to say with definity that the battery is being charged.. Might simply indicate that the battery already has a full charge. You need to be carefull that the HP alternator doesn't overheat given the limited level of cooling airflow available.

If you want see if the new alternator is actually productive at idle turn off all possible loads, check the battery post voltage, now do the same with ALL loads on.

[chadco]

Yeah it was me that put the LED bulb in before I knew it mattered, but the original bulb doesn't light up at all and it still has to be temporarily jumped to start up the charging of the system. I have about 5 bulbs of the stock style for my year of car and none of them even light up. That is why I am going to order a new socket first and make sure its not just a bad connection within the socket itself.

[wwest]

Since you can jump the bulb and kick start the alternator it must be the socket.

Aftermarket 12v LED with built in resistor or home brew?

[chadco]

bought the LED bulbs from website, said they were for Porsche 911 sc. Figured they were the right ones. Have ordered the new sockets from porsche and also a 5 watt .91 ohm resistor just in case. Thanks for all your help.

[304065]

Chadco. . .search here for "zero-ampere RPM."

[GH85Carrera]

Originally Posted by wwest

"spring plates" = 1979 SC.. which came with the external VR, inexpensive purchase and easy DIY install/swap.

Late to the party/question, but if your A/C cools satisfactorily at a consistent roadspeed, north of 2500 RPM, as mine does/did, you can get additional cooling capability at idle by lifting the heat lever just ever so slightly. The cabin heater blower comes on, with virtually no cabin heating, and the engine IDLING airflow through the rear lid condenser increases substantively.

There are also a couple of DIY methods through which you can improve the level of additional airflow provided by the cabin heat blower, even automatically with a little extra effort and coin.

Trinary pressure switch to engage the cabin blower automatic or if you don't wish to open the A/C system "this":

Senasys -

That is likely the strangest reply to an alternator problem I have ever seen. So he needs to turn on his heater to get the A/C system to blow so that is alternator will charge? That is beyond WTF. It would be funny if it were not sad. Please put down the bong and sober up before posting stoned.

[chadco]

New sockets came in and placed the LED bulb in and still same problem...no Charging. Placed resistor in parallel and still no alt excitement. Put factory bulb back in the new socket and everything works perfectly. So I guess I will leave it well enough alone and go with the factory bulb on that circuit anyway. Thanks for all the help guys :-)