Alternator D+ / 61 Terminal

[PaulRainbow]

Update.
Connected wire with in line 10 watt 39 ohm resistor between starter battery and the D+ terminal on the alternator. Voltage on the D+ terminal was 4.88V.

Started engine, left at idle, and alternator working fine.
So can safely say that this set up allows my alternator to work.

This was just a temporary solution. A planned permanent solution is to use a normally open relay to connect battery voltage to D+ via the resistor. Relay will be energised by the 12V to the starter motor solenoid.

That's pointless, just add more points of failure. Also means the wire is live anytime the isolator switch is on.

About 4 hours after removing the temporary wire and resistor I restarted the engine, and again the alternator kicked in and was working OK.

That'll just be residual magnetism.

At the moment, I'm still using the borrowed new style alarm/light module (with the LED bulbs).
I'll check again next week on next visit to the boat. If the alternator kicks in we'll call it case closed. If not, will fit the relay as shown in the diagram.

Just connect the wire with the resistor to d+ and the same terminal on the key switch as the warning lamp. That way it's only live when the key is on. Job done.

 

[nigel1]

That'll just be residual magnetism.

Or maybe not.
Back on the boat today to fit a BMV 712 battery monitor, and started engine. Alternator kicked in immediately.
So it seems that the new style alarm module was the fix.
It is possible that the "used but tested and working" module I bought may have not been working quite as well as advertised. It will be returned to seller.

Cheers
Nigel

 

[VicS]

Or maybe not.
Back on the boat today to fit a BMV 712 battery monitor, and started engine. Alternator kicked in immediately.
So it seems that the new style alarm module was the fix.
It is possible that the "used but tested and working" module I bought may have not been working quite as well as advertised. It will be returned to seller.

Cheers
Nigel

So ....You are using a new style alarm module,

• Do you have your excitation resistance in circuit or not?
• Have you fitted the replacement Sterling regulator ? If so does it make much difference to the charging rate ?
• Which alternator are you using? 60amp or 100amp.
• Have you measured the voltage at D+/61 with the ignition on but engine not running ? If so what is it now.?

 

[nigel1]

• Do you have your excitation resistance in circuit or not?
• Have you fitted the replacement Sterling regulator ? If so does it make much difference to the charging rate ?
• Which alternator are you using? 60amp or 100amp.
• Have you measured the voltage at D+/61 with the ignition on but engine not running ? If so what is it now.?

Hi Vic
1. No, additional resistor was removed.
2. No, Sterling Regulator not connected, project for next week
3. Using the new 100 amp alternator
4. Voltage 4.9V

Engine is coming out next month, needs tarting up a bit, plus replace the 25 year old insulation in the engine compartment. While the engine is out, will see if I can access that additional ignition feed (red/blue) wire at the connection/relay/fuse box on the engine. If its there, will extend it out towards the alternator and have it as a standby just in case the issue occurs again in the future.

Cheers
Nigel

 

[PaulRainbow]

Hi Vic
1. No, additional resistor was removed.
2. No, Sterling Regulator not connected, project for next week
3. Using the new 100 amp alternator
4. Voltage 4.9V

Engine is coming out next month, needs tarting up a bit, plus replace the 25 year old insulation in the engine compartment. While the engine is out, will see if I can access that additional ignition feed (red/blue) wire at the connection/relay/fuse box on the engine. If its there, will extend it out towards the alternator and have it as a standby just in case the issue occurs again in the future.

Cheers
Nigel

If you have a brand new 100A alternator, what external regulator are you fitting and why ?

 

[nigel1]

If you have a brand new 100A alternator, what external regulator are you fitting and why ?

Hi Paul

Its a Sterling regulator, reason for fitting is to get closer to the recommended charging profile for Trojan batteries.
Cheers
Nigel

 

[nigel1]

Vic,

You asked about the charging rate of the Sterling External regulator.
Fitted today. I have the external regulator sense connected to the house bank terminal on the split charge diode, and the internal regulator sense connected to the input terminal of on the split charge diode.

On starting engine, voltage at the battery terminal slowly increases to 14.8/14.9 volts (has temperature sensors connected).

Its not really a smart charger, it stays in bulk for an hour, then the external regulator in theory drops to 13.6V, but it can't do this, cannot reduce voltage below that of the internal regulator (14.4/14.5V). As the sense wire is on the input side of the splitter, the voltage at the battery terminal when in float is 13.8V.

I'm happy with the result.
Cheers
Nigel