Charging Lamp

[stretch33]

Got back into Pyfleet last nite and noticed charging lamp / aux lamp glowing, engine had been running for 15 minutes on battery 2. Changed to battery 1 and no lamps glowing. Started engine this morning on starter battery (1) then changed to battery 2 to run back upto the mooring, no lamps glowing. Got back onto the mooring left engine on tickover and the lamps were glowing again. This only seems to happen on battery 2. Any idea's ? Is it possible that the domestic batts are shot !
Phil

 

[halcyon]

Could be warn brushes in the alternator, or field diode failing intermitant.

The warning light is earthed via the rotor in the alternator, this is what starts the alternator charging. Once it starts charging two sets of diodes rectify it for charging, a third set provide a volt to keep the rotor excited, this also provides a back voltage to turn the charge light off. If for some reason the field diode voltage drops to below the battery voltage, the light will start glowing as it can earth at the alternator.

Check alternator output volts.

Brian

 

[oldharry]

Also check for dodgy connections on battery 2, particularly the negative line back to the engine or alternator chassis. Any faulty connection could effectively be cutting off the charging supply, causing the warning light to come on. This condition will rapidly destroy the alternator rectifier diodes demanding a replacement alternator, and a replacement alternator, and a replacement alternator, until rectified. (er..... sorry!)

 

[jfkal]

Guess oen battery is at the end of its live.