Hello All, I have a 2002 Silv D/A SB 4x4 with 130 amp alternator. My voltage output is 14.8 and wondering if anyone has checked theirs. Please share your info as I feel that this is a bit high. I further understand GM has set their internal regulators on the alternators to put out that much. Most reading I've done tells me that 14.2 to 14.5 is the ideal voltage output. :)

try this


http://dieselplace.com/forum/showthread.php?t=19040&highlight=voltage+high

Thanks peekok, I visited that site and it seems most are running high as well. I measured mine at the battery with a digital voltage meter and it is consistent at 14.85-14.88. No one at the link had any real answers though. If you have more info, please let me know as I'm concerned about battery life. I just replaced two of them this Oct, and noticed one had boiled out a bit. I cleaned it up with baking soda and am keeping a very close eye on it now. Thanks again, Jim

let me do some searching tommorrow and ill get back to ya. :)

Mine reads 14.7 with a good digital meter that was lab checked about 6-7 months ago.

jimjmk:

ok sorry i coudnt get back to you sooner, anyway ive dug up some facts out of some of my old basic electronics books. my truck came with 2 batteries connected in parallel. each battery being 12 volt. each battery containing 6 cells. each cell being lead acid, or gelled lead acid(maintenance free, no water needed) by the way there are many types of batteries but for cost andhigh current output lead acid is better. a charged lead acid cell voltage is 2.2 volt (gelled lead acid 2.1 volt) to charge a 12 volt lead acid battery (6 cells X 2.2 volt =13.2 volt ) the charging voltage must be more than the battery emf. approximately 2.5 volt per cell (15 volt) enough to overcome the cell emf so that the charging voltage can produce current opposite to the direction of discharge current. in a nutshell when your truck is running it would be normal to see voltage to 15 volts dc on a digital voltmeter. hope this helps.:bow:

also it looks like gm wan ts to see 16 volt before they think there is a problem.:ro)



Charging System

GENERATOR
The AD-230 and AD-244 generators are non-repairable. They are electrically similar to earlier models. The generators feature the following major components:


The delta stator
The rectifier bridge
The rotor with slip rings and brushes
A conventional pulley
Dual internal fans
A voltage regulator
The pulley and the fan cool the slip ring and the frame.

The AD stands for Air-cooled Dual internal fan; the 2 is an electrical design designator; the 30/44 denotes the outside diameter of the stator laminations in millimeters, over 100 millimeters . The generators is rated at 102 and 130 amperes respectively.

The generator features permanently lubricated bearings. Service should only include the tightening of mounting components. Otherwise, the generator is replaced as a complete unit.

REGULATOR
The voltage regulator controls the field current of the rotor in order to limit system voltage. The regulator switches the current on and off at a rate of 400 cycles per second in order to perform the following functions:


Radio noise control
Obtain the correct average current needed for proper system voltage control
At high speeds, the on-time may be 10 percent with the off-time at 90 percent . At low speeds, the on-time may be 90 percent and the off-time 10 percent .

CHARGING SYSTEM INDICATOR
The IPC illuminates the charge indicator in the message center when the following occurs:


The PCM detects that the generator output is less than 11 volts or greater than 16 volts . The IPC receives a class 2 message from the PCM requesting illumination.
The IPC determines that the system voltage is less than 11 volts or greater than 16 volts . The IPC receives a class 2 message from the body control module (BCM) indicating the system voltage.
The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds .
The ignition is on, with the engine off.

:) it also looks like the delco battery uses lead/calcium grids which can take higher charging voltage, ie- 14.8 volts;)

Thanks guys, now that's what I call thorogh and excellent info. To get you up to speed on my situation, I bought the truck with 57K in May 04. When it started getting colder, I started to realize the cranking speed was slow (didn't feel much reserve would be there either). If -5F would be questionable starting, certainly -25 and ' would be impossible. So I went to Sams and bought two new nascar 770 CCA (exide) batteries. When the boil out occured, I became suspicious of problems. I talked to a friend of mine with a 2000 Dodge cummins, and we check out mine 14.85-14.88. We then checked his and it was 14.6. He also felt it was a bit hot. So I bought a DVT and started looking into the situation further. I even called excide and told them the situation. They said no problem, that battery could handle that voltage output. So I said further, what would cause it to boil over. He said overcharge, heat, or bad plates. He also said sometimes the people operating the fork lifts drop the ballets and then you have problems. We'll see if I have any more problems.