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Brand X 320a alternator problems


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I recently purchased a Brand X 320a Denso alternator (internally regulated) for a 98 Toyota 4runner. I'm having an issue with output at idle. It drops to 11.9-12.1v at idle but reaches 14.8v like it should at about 1100 RPM. The alternator was advertised to put out 160a at idle and nothing was mentioned about having to raise my idle speed. It has a 1.7in pulley and I'm pretty sure a smaller pulley doesn't exist.  The sense wire is connected to the positive battery terminal (I've also tried  connecting it directly to the alternator positive stud) and I ran the ignition line into the ACC fuse using an add a fuse. The alternator came with a harness that was supposed to be plug and play, but after that didn't work I ran it myself to be sure. There is a 470 ohm 1/2 watt resistor on the ignition line which Brand X is saying it needed to not "pop" the regulator. I've replaced the belt and there is no noticeable slip (I've cranked the tension up for testing to be sure), I've tried 2 AGM batteries, 1 that I know is good and one that is brand new) I have a few Yinlong lithium banks, I just haven't installed them yet as the build is far from done). I've re-ran my power and grounds (brand new 0awg OFC, soldered terminals), all runs are less than 3ft, grounded to the chassis and I verified the connections are solid (angle grinder to bear metal). I've tested the rectifier bridge on the alternator which tested fine. My old alternator(140a) puts out 14.8v at idle with no issues. 

 

During testing, a few random times the alternator held 14.8v like it should at idle. This usually happens after holding the RPM at ~1100 for about a minute and then letting it drop back down. It will hold 14.8v indefinitely until I restart the engine. After a restart, the idle is back to ~12v. This doesn't happen every time either, I've only been able to recreate it a few times. 

 

It's been really difficult to get solid help from Brand X, they immediately blamed my install. After assuring them it isn't (I don't think they're convinced) I asked if I needed a smaller pulley. They said the correct way to fix it would be to raise my idle RPM. I told this is not a possibility. They are saying that I can send it back so they can lower the output which I guess will fix the issue?

 

Before I send it back I figured I would reach out here as I find it odd how it randomly will put out the correct voltage at idle. Is there any thing else I could test?

 

Any help would be appreciated.  

 

 

 

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