Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (July 2001, week 1)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Thu, 5 Jul 2001 22:22:39 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      On the mirth of 130 amp alternator ratings!
Comments: To: dbeierl@attglobal.net
Content-Type: text/plain; charset="US-ASCII"

During my travels to and fro various electrical jobbers getting Alternators and Starters "rebuilt" I came to make the acquaintance of several techs doing the work. During this period I came to understand the modular nature of the Bosch alternator. For a given central segment, there were many front assemblies, still more pulleys, multiple back ends, several different regulators and basically one diode board. The difference between a 65 amp alternator and a 130 amp one was that the diode board was populated with twice as many diodes as the 65. For any given center section (defines a class of alternators) there is a maximum number of diodes that can be accommodated on the board, therefore a maximum rating. As you know, the current carrying capacity of a diode is a strong function of the temperature. In order to meet the 65 amp continuous rating, the alternator probably has to be immersed in solid CO2.

In any case, the only way to look at these ratings is that a 130 amp unit will put out twice as much current as a 65. Of course, for any given current draw (say 47 amps as in when I'm heading across Texas with the stereo cranked and Wagner on the deck) the more the diodes, the less the diode board temperature and that translates into longer times between stops at the Alternator jobber.

Alistair's tip about the Audi air baffle on the back of the alternator translated into big lifetime savings and increased output. The cost of having the tech mix and match the Porsche 944 tail with the Vanagon front and the 928 diode board was minor. The confusion at a VW show when a purist tries to figure out when VW mounted this alternator is truly priceless.

Frank Grunthaner


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.