Volvo Penta MD22L alarm panel function

[watercraft]

Hi I’m having charging issues and the ignition panel is not supplying a live exciter feed to the alternator.
The logic of the alarm panel (LED version) doesn’t illuminate the water temp light but also doesn’t output a +12v on the brown wire which goes to the alternator.
It all suddenly stopped charging after 2hrs use on a warm sunny day.
so I purchased a new panel - same problem so it’s either blown the new panel or I’m not understanding things correctly.
Any suggestions? Thanks

 

[VicS]

An LED warning light does not provide a high enough current for the initial alternator excitation

Later engines, with the LED panels , have an additional excitation resistor to provide the current. Item 9 in the attached diagram . I forget the exact value but about 50 ohms will be suitable but will need to be a 5 watt one .
Its fed with 12 volts when the ignition is on. but your wiring harness may not have the connection through pin 3 on the multipin connectors ????

 

[watercraft]

An LED warning light does not provide a high enough current for the initial alternator excitation

Later engines, with the LED panels , have an additional excitation resistor to provide the current. Item 9 in the attached diagram . I forget the exact value but about 50 ohms will be suitable but will need to be a 5 watt one .
Its fed with 12 volts when the ignition is on. but your wiring harness may not have the connection through pin 3 on the multipin connectors ????

View attachment 116367

Thank you this makes sense and you’re correct pin3 is missing. I’ve also got an earth or power issue to the switch as the engine shut off is now not working - I’ll have to get a decent multimeter and test out the wiring loom and the terminals.
I measured the current draw from the alternator which is 3.4 amps (connected to 12v feed) however the alternator didn’t seem to start charging when I did this.
I had a similar problem 2 years ago no engine shut down no charging I cleaned all the terminals all ok. This time it hasn’t worked.

 

[VicS]

Thank you this makes sense and you’re correct pin3 is missing. I’ve also got an earth or power issue to the switch as the engine shut off is now not working - I’ll have to get a decent multimeter and test out the wiring loom and the terminals.
I measured the current draw from the alternator which is 3.4 amps (connected to 12v feed) however the alternator didn’t seem to start charging when I did this.
I had a similar problem 2 years ago no engine shut down no charging I cleaned all the terminals all ok. This time it hasn’t worked.

A test lamp on a couple of leads is often more useful than a multimeter. The trouble with digital voltmeter meters is that they draw so little current that they will give a normal reading even through a bad connection. Sooner or later they will make a fool of you ( I have the tee shirt)

 

[watercraft]

A test lamp on a couple of leads is often more useful than a multimeter. The trouble with digital voltmeter meters is that they draw so little current that they will give a normal reading even through a bad connection. Sooner or later they will make a fool of you ( I have the tee shirt)

Thanks this is good advice.
I’ve sorted the engine shut off issue (using multimeter) a diode had an internal intermittent connection (pektron 16.24.39) which is on the engine shut off solenoid circuit. Replaced with spare happy days.
Engine temp alarm sensor/switch is faulty this was causing my temp light to not illuminate however my charging issue still exists.
going to wire in a separate 5amp feed to the alternator exciter and change the alternator power leads to the main heavy duty cable as well.
then if this doesn’t work take alternator for testing.
there is a charge diode not sure how to test this?
thanks

 

[VicS]

Thanks this is good advice.
I’ve sorted the engine shut off issue (using multimeter) a diode had an internal intermittent connection (pektron 16.24.39) which is on the engine shut off solenoid circuit. Replaced with spare happy days.
Engine temp alarm sensor/switch is faulty this was causing my temp light to not illuminate however my charging issue still exists.
going to wire in a separate 5amp feed to the alternator exciter and change the alternator power leads to the main heavy duty cable as well.
then if this doesn’t work take alternator for testing.
there is a charge diode not sure how to test this?
thanks

What do you mean by a "charge diode " A diode splitter for charging two batteries ?

Diodes can easily be tested with a digital multimeter with a diode test range........... maybe on one of the resistance ranges if no diode test range ..... or with an analogue multimeter on a resistance range

 

[watercraft]

What do you mean by a "charge diode " A diode splitter for charging two batteries ?

Diodes can easily be tested with a digital multimeter with a diode test range........... maybe on one of the resistance ranges if no diode test range ..... or with an analogue multimeter on a resistance range

Ok thanks these beasts can be tested in the same way as a small diode would? Do I need to apply a current to turn it on? .... I’m more mechanical ....thanks

 

[watercraft]

What do you mean by a "charge diode " A diode splitter for charging two batteries ?

Diodes can easily be tested with a digital multimeter with a diode test range........... maybe on one of the resistance ranges if no diode test range ..... or with an analogue multimeter on a resistance range

Diode tested ok the wires I mentioned go to a solenoid to isolate the battery feed. Thanks.