VWDiesel.net The IDI, TDI, and mTDI source.

General Information => Troubleshooting => Topic started by: motomike33y on April 07, 2010, 09:48:33 am

Title: alternator/charging battery question
Post by: motomike33y on April 07, 2010, 09:48:33 am
replaced volt reg on alternator, charging at 14v per my new gauge.  yesterday suddenly dropped to 10v. replaced connector that was poor, but still only 10v-also checked w/voltmeter.  alternator has other issues so I'm replacing it..but in the meantime, will 10v charge battery somewhat, or am I running completely off battery?  I'm charging it at night, but wonder how long before I get stranded and have to use my jumpers.  thanks
Title: Re: alternator/charging battery question
Post by: truckinwagen on April 07, 2010, 10:04:02 am
anything less than 14.4 will not charge a battery very well, and 10 is doing nothing.


-Owen
Title: Re: alternator/charging battery question
Post by: motomike33y on April 07, 2010, 10:52:05 am
that was my fear-will start and drive as little as I can before new alternator arrives(hopefully by weekend)-good thing it doesn't take lots of spins to start it
Title: Re: alternator/charging battery question
Post by: Rabbit on Roids on April 07, 2010, 10:55:16 am
that was my fear-will start and drive as little as I can before new alternator arrives(hopefully by weekend)-good thing it doesn't take lots of spins to start it

if you dont use the headlights, or heater, or anything that has a pretty good current draw, you will be able to drive around for at least a whole day on a fully charged battery. if nothing else is on, the fuel stop solenoid should be the only thing drawing power. and it takes almost none. when you start running your head lights and heater fan, then the battery will start to lose power quick.
Title: Re: alternator/charging battery question
Post by: motomike33y on April 07, 2010, 11:07:54 am
heater fan runs at low level whenever the key is on, so I'll be careful otherwise.  glow plug is big big draw I assume.
Title: Re: alternator/charging battery question
Post by: bajacalal on April 07, 2010, 11:28:35 am
I drove across the state of Oregon with no working alternator and with the headlights and windshield wipers on! With a diesel you should be able to go a long way.

Make sure your blue exciter wire is good and connected and delivering ~ 12 volts. Also check the wiring coming from the alternator.

Title: Re: alternator/charging battery question
Post by: motomike33y on April 07, 2010, 11:47:26 am
I checked the voltage at the alternator w/voltmeter and it also is 10, like on my inside gauge.  If yours was 12, then maybe it was charging some.  I'm not worried since once it starts, it will run forever almost-I'm worried about the glow plug cycle, starter draw, which is a substantial drain, and if 10v doesn't replace any, then potential problems when I next try to start.
Title: Re: alternator/charging battery question
Post by: bajacalal on April 07, 2010, 12:09:33 pm
I meant check the blue wire when the key is in the ON position, engine off, it should have battery voltage as the alternator has to be "primed" so to speak... Without that it will not reliably start producing voltage.

I think you should get a few good starts off a battery, I measured it once, iirc the battery output dropped something like 1/2 volt each time I attempted to crank it for about 3 seconds and cycled the glow plugs.

If you are not making a lot of stops, not driving at night/during rain and you should be fine, especially since you are charging the battery at night which should put you back to a completely charged battery each time.
Title: Re: alternator/charging battery question
Post by: motomike33y on April 08, 2010, 05:17:30 am
I got 4 starts, unfortunately the 5th was leaving work.  Fortunately, I only had to walk a block to carry the battery to my charger-we'll see how many I get today.  New alternator is supposed to arrive tomorrow pm.
Title: Re: alternator/charging battery question
Post by: motomike33y on April 12, 2010, 12:14:27 pm
New alternator installed friday nite and took care of problem, now charging at 15 volts.
Title: Re: alternator/charging battery question
Post by: somolovitch3 on April 13, 2010, 07:06:52 pm
13.8 anyone?
Title: Re: alternator/charging battery question
Post by: motomike33y on April 14, 2010, 11:28:54 am
I didn't check w/my volt meter,but my in-car gauge shows 15, and showed 10 when it wasn't working right.  That matched with 10 at voltmeter, and prior alternator matched at 14 when running.
Title: Re: alternator/charging battery question
Post by: 8v-of-fury on April 15, 2010, 08:34:57 am
15 when running will charge a battery up real good. ;)