---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 03/28/11: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:20 AM - Re: apparent alternator issue (racerjerry) 2. 06:21 AM - Re: apparent alternator issue (racerjerry) 3. 07:10 AM - Re: apparent alternator issue (Robert L. Nuckolls, III) 4. 03:31 PM - Re: apparent alternator issue (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:20:59 AM PST US Subject: AeroElectric-List: Re: apparent alternator issue From: "racerjerry" A loose / dirty / corroded wire between alternator and regulator can easily fool the regulator into thinking that the battery is fully charged. Dont forget the ground straps and make sure that the alternator is solidly grounded. Easiest first step is to pull and clean all battery connections. When done, a little petrolatum on the heavy terminals will keep things shiny for a long while. Look carefully for a loose or broken connection at the small wire terminals on the alternator. Because of vibration, alternator connections often open up. Wires rarely fail in the middle unless rubbing or another form of abuse takes place. Any wire problem generally appears at the termination. You could check for excess resistance using a digital voltmeter. Intermittent problems can be tough to locate, but wiggle any suspect connection and watch for a change in resistance. It is possible that a diode within the alternator went bad, which would cut the alternator output by one third, but I doubt it because diode failure is rarely intermittent. If your wiring checks do not reveal anything, you might consider removing the alternator and taking it down to the good folks at AutoZone. With their test machine, they can do a quick free diagnosis. They didnt even ask me what car it was from. Good luck. -------- Jerry King Read this topic online here: http://forums.matronics.com/viewtopic.php?p=335246#335246 ________________________________ Message 2 _____________________________________ Time: 06:21:14 AM PST US Subject: AeroElectric-List: Re: apparent alternator issue From: "racerjerry" A loose / dirty / corroded wire between alternator and regulator can easily fool the regulator into thinking that the battery is fully charged. Dont forget the ground straps and make sure that the alternator is solidly grounded. Easiest first step is to pull and clean all battery connections. When done, a little petrolatum on the heavy terminals will keep things shiny for a long while. Look carefully for a loose or broken connection at the small wire terminals on the alternator. Because of vibration, alternator connections often open up. Wires rarely fail in the middle unless rubbing or another form of abuse takes place. Any wire problem generally appears at the termination. You could check for excess resistance using a digital voltmeter. Intermittent problems can be tough to locate, but wiggle any suspect connection and watch for a change in resistance. It is possible that a diode within the alternator went bad, which would cut the alternator output by one third, but I doubt it because diode failure is rarely intermittent. If your wiring checks do not reveal anything, you might consider removing the alternator and taking it down to the good folks at AutoZone. With their test machine, they can do a quick free diagnosis. They didnt even ask me what car it was from. Good luck. -------- Jerry King Read this topic online here: http://forums.matronics.com/viewtopic.php?p=335247#335247 ________________________________ Message 3 _____________________________________ Time: 07:10:30 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: apparent alternator issue At 08:57 PM 3/27/2011, you wrote: > >I have a vp100 and single alternator, single battery, 2 EFIS chelton >system similar to Z11 type wiring diagram I have the 60 amp alternator recommended by VAN's, but rarely use more than 30-35 continuous. Even so, I frequently get battery drain warning below 12.5 volts, and I have to conserve. But it is very inconsistent and for some unknown reason it will bounce back up above 13.5 and charge along just fine. Your normal bus voltage should be on the order of 14.2 to 14.6 volts. I don't think it is the battery, because I'm not finding any problems on the starting side. But the problem does seem to be getting worse. Voltage issues while in flight are never a battery issue. If your alternator has a built in regulator, then it's a very high probability of being bad. The fact that your 'normal' bus voltage is so low suggests that it may have had some kind of problem right out of the box. Bob . . . ________________________________ Message 4 _____________________________________ Time: 03:31:27 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: apparent alternator issue At 08:57 PM 3/27/2011, you wrote: > >I have a vp100 and single alternator, single battery, 2 EFIS chelton >system similar to Z11 type wiring diagram. > >I'm having trouble with my alternator charging. Although I have a >50 amp load analysis (if I have everything turned on and max) I have >the 60 amp alternator recommended by VAN's, but rarely use more than >30-35 continuous. When you say "alternator recommended by Van's" is this the 60A PlanePower product? When working with alternators having built-in regulators, there's not much you can do to troubleshoot a voltage variation except to monitor the b-lead terminal with a test voltmeter to see if readings at the b-lead agree with readings on the panel displays. If you have two panel displays and they agree to within .5 volts of the b-lead terminal, then your alternator is probably in need of attention. If the b-lead says where it belongs, 14.2 or a little better, then there's a wiring problem. A wiring problem that drops 2 volts at 30+ amps is going to dissipate some heat. If something 'loose' is your root cause, then it's likely to have a somewhat cooked appearance. 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