Charging System Issues
 

Replaced alternator several months ago after fully discharged battery/highway breakdown. Every since, I've continued to have battery failures and charging issues. I trickle charge using Battery Tender nightly but the problem persists.

After another discharged battery no-start episode (4 or 5 total occurrences now since replacing the battery with a new 850 amp Interstate) took car to local wrench to have battery checked thinking battery/ cell was bad. System diagnostic indicated that the battery was "good" but there are problems with the charging system. Specifically, charging voltage under "no load" was 12.43V (tech states normal reading should be 13.5V min) and 0.00V under "load" with "no charging diode detected" noted.

Assuming my reman alternator installed 2 mod ago is bad, I have contacted Pelican to send a replacement unit as it is covered under warranty. If for some reason I have the same condition after replacing the alternator again any troubleshooting recommendations for "no charging diode detected" situation?

Thanks!

I'm going to ask the stupid question first, so please don't think I'm being a smartass: does your alternator light on your dash illuminate when you first turn on your ignition?

Interesting. What tool did he use to diagnose the no charging diode? Not in my tool set, that's for sure.

He is right as to the 13.5 plus. I have seen high 13's on the few I have replaced tired V regs on.

I bet the alternator was just not re-manufactured properly as even the reman unit I purchased from Advanced Auto last year is cranking out voltage ok.

FWIW - Wish I had the coin to drop on one of the new high output alternators PP sells.

Good point. It was not mentioned. Shouldn't it?

Yes, alt light comes on on start up and then goes off normally after start up. Light has never come on indicating discharge or charging problem thereafter - even as battery dies.

Diagnostic tool is a Midtronics 500. Costs $599, see here

Midtronics Battery Tester - Micro 500

Performs (1) "Battery Test", (2) "Starter Test" and (3)"Charging Test"

My results were (1) 12.6V Good Battery (2) Cranking voltage normal at 11.33V and (3) Charging System Problem - No Charging Voltage - load off 12.43V load on 0.00V - Diode Ripple Not Detected.

Reman alternator was a Bosch Reman Unit from Pelican took 3 shipments as first was defective (bad spot weld on exciter diode) and second was damaged in shipping. Major PITA.

From what I understand, the high output alternators requires replacing the alt housing with a Vertex unit making the upgrade pretty pricey.

Thanks for the info. Hmmm on the parts problems.

The throw it on the ground video is great.

I offer:

Whole Foods Parking Lot - Music Video [HD] - YouTube

alternators
 

i had problems with fitment, quality and longevity with remanufactured alternators.
i took my original one to an alternator shop in pittsburgh, Stellar, no affiliation.

the guy rebuilds any make of starter and alternator, he showed me that the porsche diodes are pressed into the alternator and are well made whereas the remanufactured use externally mounted diodes that are soldered to posts. i had him redo mine and he used the better diodes, that was about 2 years ago, i have not had any problems since.

i bought another alternator on ebay or here i forget and had it rebuilt by him so when one fails i can swap and be on the way again.

Poor ground somewhere? More likely than you think...trust me. Check the usual transmission ground strap and also the negative battery post to chassis--this is where mine was.

above ^^^

check grounds/connections first.
if you pull the alt back out, you may take it down and have it tested out of the car, just to make sure before you send it back.