I have a similar problem in my 14-volt system. BNC told me to put a resistor in parallel with the LED warning light, as the leakage through the circuit was enough to cause the LED to glow. That helped, but when the system is cold the light still glows. It goes out when either the ambient or circuit temperature goes up - I'm not sure which. Since I have a voltage indication with an independent warning, I ignore the light during runup. After a few minutes of flight the light goes
out. I've just lived with it.
Gary Casey
ES, IO-540, complete BNC electrical system (battery, alternator, regulator)
<html> <head> <style> <!-- p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue;text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {color:purple;text-decoration:underline;} span.EmailStyle17 {font-family:Arial;color:windowtext;} _filtered {margin:1.0in 1.25in 1.0in 1.25in;} div.Section1 {} --> </style> </head> <body lang="EN-US" link="blue" vlink="purple"> <div class="Section1"> <p class="MsoNormal"><font size="2" face="Arial"><span style='font-size:10.0pt;font-family:Arial;'>Dear subscribers,</span></font></p> <p class="MsoNormal"><font size="2" face="Arial"><span style='font-size:10.0pt;font-family:Arial;'>
</span></font></p> <p class="MsoNormal"><font size="2" face="Arial"><span style='font-size:10.0pt;font-family:Arial;'>I am using a bnc regulator on a TSIO550 with a teledyne alternator on my 4P.