Charging question

I was just told that my car needs to idle at least 800 rpm's before the HO alternator will charge. I have been using it for 21 months with no problems. Now when it idles, it shows that it is discharging some. This sounds fishy to me, seeing how it has a 24 month warranty. If I rev it up a little it will charge normally. Does this sound correct or are they trying to pull one over on me?  '85 Toy

That sounds normal to me.Support the12volt.com

yep normal it takes a bit of rpm to get teh alternator to charge, even your factory one will need to get some rpm, 800 isn't that high some have needed 1000

So, how do I get the car to idle up? It is an '85 Toyota Supra, and it doesn't have an adjustment on the idle speed. And why has it been working fine for 21 months, until last week, when it started doing this? '85 Toy

Seems to me that anytime I've had that happen it was a weak or worn out battery.

I'll have the battery checked. It is only 6 or 7 months old (Platinum series from Advance Auto), but I know even a new battery can be bad. It don't give any trouble cranking though. But I guess it could be weak.'85 Toy

OK, I checked with Toyota, and 650 rpm's IS normal idle for 85 Supra's once they warm up. There is no adjustment. My battery checks out fine. I had no trouble for 21 months with this alternator. To me, this points directly to the alternator giving problems. Any other ideas? I still have the factory one, so I guess I'll put it back on the car and see if this problem goes away. I have stood up for alterstart several times, on this forum, and to any body I've seen. But after the way they talked to me on the phone the other day, very rude and short, I will buy elsewhere from now on if I need another one.'85 Toy

that really does sound normal for a ho alt. what kind of system do you have or how many amps are you drawing, I would suggest going to a yellow top

It is discharging at idle with the stereo off, nothing but the headlights and heater blower on. It worked for 21 months with no problem, even playing the stereo while idle. That is the part that is frustrating me. If this is normal, why did it work for so long before it started doing this?'85 Toy

if your a battery is not getting enough to charge when you are just running minor acc's, there is a problem with the alternator for sure. It may also be the voltage regulator. Which I believe is internal in the alternator, or is also an external unit depending on the make and model of car