Puzzled by battery light on engine control panel

[Gerry]

We have a Perkins M50 which does not seem to be charging very aggressively (normally 3 to 5 amps) and when running still shows a dim red light on the control panel with the picture of a battery on it. This warning light is, of course, much brighter when we have just turned the ignition on and have yet to press the start button.

Does anybody have any ideas on what the possible problems could be?

 

[little_roundtop]

Your alternator is almost certainly not charging. Put a digital voltmeter across the batteries with the engine running, it should read well over 13 volts (and probably over 14v depending on the state of charge of your batteries) if it doesn't then your alternator is certainly not charging. The most likely cause is excessive brush wear, these are easily replaced, though it means taking the alternator off and breaking it down to get at the brushes. Any competent auto-electician could do this for you too.

 

[Gerry]

Thanks, we'll try changing the alternator, we carry a spare!

 

[sailorman]

Your alternator is almost certainly not charging. Put a digital voltmeter across the batteries with the engine running, it should read well over 13 volts (and probably over 14v depending on the state of charge of your batteries) if it doesn't then your alternator is certainly not charging. The most likely cause is excessive brush wear, these are easily replaced, though it means taking the alternator off and breaking it down to get at the brushes. Any competent auto-electician could do this for you too.

or a bad connection from the ing. switch to the bulb