Machspeed Posted May 27, 2021 Share Posted May 27, 2021 I've got an issue here that I need some advice on. I did the 3G alternator mod a few months back, also had my ammeter converted to a voltmeter. Not sure that meter was calibrated correctly, as it read something like 18 volts at the gauge. Measured at the battery it was 14.6 charging. Aside from the gauge reading, all else seemed fine. I've been doing a lot of work on the truck since the alternator mod and I've kept the negative battery cable off. The other day after changing out the power steering pump, I fired it up to note that the volt meter was reading very low. At the battery it was measuring 12.06 volts charging. Frustrated and thinking my relatively new DB alternator had crapped out on me, I just shut the hood and walked away. I did not not, however, remove the negative cable. Yesterday, I went out to look at it and the battery was dead. Battery was measuring 6 volts. Took the 6 year old battery in for charging and it took the charge and checked out as good. Did a parasitic draw test tonight and got the below numbers. That is huge! No key in the ignition, no lights on, nothing! What would cause that kind of amp draw? Thanks! Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 28, 2021 Share Posted May 28, 2021 Yup, .6A is huge. I'm guessing that you may have blown diodes in the rectifier bridge in the alternator. Or maybe a bad regulator. So I'd pull the charge cable off the alternator and test for parasitic draws again. I'll bet it goes to .01A or so - assuming you have the door closed and the underhood light turned off. Yes? Link to comment Share on other sites More sharing options...
grumpin Posted May 28, 2021 Share Posted May 28, 2021 Yup, .6A is huge. I'm guessing that you may have blown diodes in the rectifier bridge in the alternator. Or maybe a bad regulator. So I'd pull the charge cable off the alternator and test for parasitic draws again. I'll bet it goes to .01A or so - assuming you have the door closed and the underhood light turned off. Yes? I just found a pretty big draw on my Xterra. Found it was the stereo. Pulled it today to make sure it was wired correctly, it was. Something in there is wacky. Going to put another stereo in it. Just in case it isn’t related to your recent conversion. Link to comment Share on other sites More sharing options...
Machspeed Posted May 28, 2021 Author Share Posted May 28, 2021 Yup, .6A is huge. I'm guessing that you may have blown diodes in the rectifier bridge in the alternator. Or maybe a bad regulator. So I'd pull the charge cable off the alternator and test for parasitic draws again. I'll bet it goes to .01A or so - assuming you have the door closed and the underhood light turned off. Yes? Thanks Gary, I remember you telling me that and thought about it while I was taking the amperage readings, though I did not pull the charge cable. I may do that this evening. Regardless, I ordered up a new alternator from AZ last night with a lifetime warranty. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted May 28, 2021 Share Posted May 28, 2021 I've never seen a start battery fully recover from a 6 volt reading. 💀 Your meter has a diode test function. Why don't you use it before condemning the rectifier? Disconnect the charge lead from the alternator end and see if the draw goes away. Was the ltG/R wire hot in start and run? What kind of reading did you get when you grounded the field screw? Link to comment Share on other sites More sharing options...
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