Installing an external regulator on a Volvo D2-55

[James HR40]

In order to improve the charging efficiency of the alternator when using the auxiliary engine to charge the 4 Trojan T-125 wet cell service batteries on my HR40 I am in the process installing a Mastervolt Alpha Pro III smart external regulator on the original 115A alternator that came with the Volvo D2-55.

I attach a diagram of my understanding of the existing alternator wiring based on the HR40 and Volvo Penta manuals, a diagram of my proposed new wiring for the Alpha Pro, the wiring diagram for the Alpha Pro from the installation manual and a picture of the connections on the back of the existing alternator (N-type from Mitsubushi).

The installation requires the internal regulator on the alternator to be disabled, the negative (blue) field wire from the Alpha Pro to be connected to the negative brush and the positive (red) field wire from the Alpha Pro, which is also connected to the service battery bank, to be connected to the D+ terminal which connects to the positive brush. A local alternator specialist can help me with the modifications to the brushes.

As the Alpha Pro uses the Reg-on connection as the voltage sense from the service battery bank and I believe a relay using the existing Reg-on wire from the Volvo MDI which draws its power from the start battery is required to activate the new Reg-on connection. This will ensure the new Reg-on connection activates in the same set of conditions as the existing Reg-on connection and will thus protect the diodes.

I believe the existing fused yellow sense wire which currently connects the service battery bank to the S terminal on the alternator can be used for the Alpha Pro Reg-on battery connection.

Has anyone been through a similar experience and can validate my proposed wiring . . . and the need for the relay?

[lmxr]

Originally Posted by James HR40

[...]the positive (red) field wire from the Alpha Pro, which is also connected to the service battery bank, to be connected to the D+ terminal which connects to the positive brush.

I understand that the field power diode set in the alternator will be removed and that the field is instead powered from the house battery? If not, the house battery will be charged by the alternator through the field diode set, which cannot handle this current.

A local alternator specialist can help me with the modifications to the brushes.

I don't immediately see what modifications the brushes would need? The two brush terminals are also rather easily accessible from the outside, if I remember correctly. The more difficult job lies in disabling the internal regulator.

As the Alpha Pro uses the Reg-on connection as the voltage sense from the service battery bank and I believe a relay using the existing Reg-on wire from the Volvo MDI which draws its power from the start battery is required to activate the new Reg-on connection. This will ensure the new Reg-on connection activates in the same set of conditions as the existing Reg-on connection and will thus protect the diodes.

What is your reasoning behind that doing so will protect the diodes?

I believe the existing fused yellow sense wire which currently connects the service battery bank to the S terminal on the alternator can be used for the Alpha Pro Reg-on battery connection.

Has anyone been through a similar experience and can validate my proposed wiring . . . and the need for the relay?

I'm not sure whether the VP MDI will be happy seeing a relay instead of the alternator D+. In normal operation, the D+ provides a voltage of around 14 to 16 V, while a relay does not. The MDI might see this as a faulty alternator and enable an alarm. Easy to test: connect the MDI D+ to a relay coil and see whether there are any alarms. I'm also not sure whether the MDI keeps this output high or only briefly provides a pulse after startup.

[GordMay]

Greetings and welcome aboard the CF, James.


Yours is the most carefully, and fully, formulated first post, I recall seeing, on CF.

[Stu Jackson]

Originally Posted by GordMay

Greetings and welcome aboard the CF, James.


Yours is the most carefully, and fully, formulated first post, I recall seeing, on CF.

I agree, and welcome.

Don't know if you know of Maine Sail, a frequent contributor here and on other boating forums, is a quality boat electrical systems installer, who has developed a very good website of his own: www.marinehowto.com.

He has a number of articles on alternators and regulators. Most external regulators we see on boating forums relate to the Balmar versions, yours is or will be new to many of us (except those who have them). IIRC, he wrote up one of changing from internal to external - I know, the opposite of what you are doing, but it may help.

Here's a link:

Converting a Leece Neville Alternator to External Regulation by Maine Sail
http://c34.org/bbs/index.php/topic,4879.0.html

He also had an older website, pbase, and contributed on sbo.com. Here are some from those:
How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail): http://forums.sbo.sailboatowners.com...d.php?t=125392

Alternators & Voltage Sensing (by Maine Sail):http://www.pbase.com/mainecruising/r...oltage_sensing


I suggest looking around there for more info.

Maine Sail has recently had a stroke and is hopefully recovering, and so can't answer here or on his own site.

Good luck.

[dansken]

This is the best for your alternator https://nordkyndesign.com/product/no...ce-controller/

[Kiwi Dave]

https://www.youtube.com/watch?v=hMDwdKWsVgE&t=31s

Hi - for my catamaran I got the auto electrician to change a pair of Volvo (Mitsubishi) D1-30 115 amp alternators to external regulation and used 2 x Balmar External Regulators (MC-614) to supply the charging bus to the 400 AmpHour Lithium Iron Phosphate (LiFePO4) house bank, then 2 x Balmar Digital Duo (DDC-12/24) DC-DC Chargers to charge the AGM Engine batteries from the house bank.
The video shows the breaking into the MDI wiring harness to get the +12 volt signal to turn the regulators on.

[donradcliffe]

Converting your alternator to external regulation is as simple as removing or isolating the internal regulator wiring, then connecting one brush to the field supply from the external regulator, and the other to ground (P type regulator) or the battery *N type). Most external regulators are P type, while most internal regulators are N type. You can DIY with a heavy soldering iron. For some alternators you can buy a 'brush block" which replaces the old brushes and internal regulator.

[James HR40]

A very big set of thank you’s to everyone who has so far replied to my post. There is a lot of helpful information to digest and follow up on. In terms of my knowledge I feel I am now moving out of the shallow end of the swimming pool and into the to the part where my feet are no longer touching the bottom!

A few additional points of reference:

1. I selected the Mastervolt Alpha Pro as I already have a Mastervolt MassCombi Ultra inverter/charger and a Mastervolt EasyView Display at the chart table which enables me to easily monitor the system and also modify the charging parameters. The Alpha Pro is also set up for installation on an N- type alternator.
2. Along with the external regulator I will be installing a Mastervolt shunt to assist the service battery monitoring which will also be linked into the Masterbus network. This will replace the existing MICC shunt.
3. My boat, a Hallberg Rassy 40, is now laid up in southern Brittany in France for the winter and as I live in UK I will probably not return until the spring. I intend to use the coming weeks to confirm the wiring, plan the installation and modify the alternator for use with an external regulator.

[lmxr]

Originally Posted by James HR40

[...]
2. Along with the external regulator I will be installing a Mastervolt shunt to assist the service battery monitoring which will also be linked into the Masterbus network. This will replace the existing MICC shunt. [...]

I'm not 100% sure but I *think* that the Alpha can use the Mastervolt shunt as a battery voltage sensor? Then you won't require the trick with the relay?

[James HR40]

Originally Posted by lmxr

I understand that the field power diode set in the alternator will be removed and that the field is instead powered from the house battery? If not, the house battery will be charged by the alternator through the field diode set, which cannot handle this current.

I don't immediately see what modifications the brushes would need? The two brush terminals are also rather easily accessible from the outside, if I remember correctly. The more difficult job lies in disabling the internal regulator.

What is your reasoning behind that doing so will protect the diodes?


I'm not sure whether the VP MDI will be happy seeing a relay instead of the alternator D+. In normal operation, the D+ provides a voltage of around 14 to 16 V, while a relay does not. The MDI might see this as a faulty alternator and enable an alarm. Easy to test: connect the MDI D+ to a relay coil and see whether there are any alarms. I'm also not sure whether the MDI keeps this output high or only briefly provides a pulse after startup.

Thanks so much for your input. In response
1. Is the field power diode set part of the internal regulator? If not, is this another point to request the alternator specialist to deal with (in addition to removing/disabling the internal regulator and soldering the negative field wire to the negative brush)?
2. The main job for the alternator specialist is to remove/disable the internal regulator
3. My reasoning for the relay is that the conditions for the MDI switching on and switching off the supply of current to the Reg-on terminal will not change and thus there will be no danger of open circuiting the alternator and blowing the diodes
4. Re what the VP MDI expects to see for the Reg-on. Would it be helpful to ask the alternator specialist if the alternator expects a constant voltage or a pulse on start up? I am unable to check this on the boat until the spring as she is laid up for the winter in Brittany, France.

[James HR40]

Originally Posted by lmxr

I'm not 100% sure but I *think* that the Alpha can use the Mastervolt shunt as a battery voltage sensor? Then you won't require the trick with the relay?

That would certainly simplify things. There is no mention in the Alpha Pro installation manual of an option for picking up the service battery voltage from a Mastershunt but I will check with Mastervolt UK tech support.

[James HR40]

Originally Posted by Kiwi Dave

Hi - for my catamaran I got the auto electrician to change a pair of Volvo (Mitsubishi) D1-30 115 amp alternators to external regulation and used 2 x Balmar External Regulators (MC-614) to supply the charging bus to the 400 AmpHour Lithium Iron Phosphate (LiFePO4) house bank, then 2 x Balmar Digital Duo (DDC-12/24) DC-DC Chargers to charge the AGM Engine batteries from the house bank.
The video shows the breaking into the MDI wiring harness to get the +12 volt signal to turn the regulators on.

Hi Dave.
The wiring for the Alpha Pro is probably different from the Balmar. Was the red 12V ignition-on wire from the MDI the same as the R10 wire from the harness to the starter motor shown in the attached VP wiring diagram?
For the Alpha Pro the +12V supply wire is also used for the battery voltage sense.

[lmxr]

Originally Posted by James HR40

Thanks so much for your input. In response
1. Is the field power diode set part of the internal regulator? If not, is this another point to request the alternator specialist to deal with (in addition to removing/disabling the internal regulator and soldering the negative field wire to the negative brush)?

I don't expect the diodes to be part of the internal regulator. If you decide to disconnect the field diodes from the positive brush, I suggest that you keep the diodes connected to the D+ such that you can still present a D+ to the VP MDI... because the MDI might alarm when it does not see a D+.

[...] 3. My reasoning for the relay is that the conditions for the MDI switching on and switching off the supply of current to the Reg-on terminal will not change and thus there will be no danger of open circuiting the alternator and blowing the diodes

While the MDI can enable the alternator by pulling the D+ high, I don't think that it can disable it. It can turn of the supply but the alternator keeps itself powered on as long as the engine runs. I'm afraid the MDI can't do anything to protect the diodes. Perhaps I'm missing something in your reasoning.

Open circuiting a running alternator is certainly something to avoid, so good job thinking about this issue. A few companies sell surge protection devices that are said to deflect the surge to acceptable levels. The risk of open circuiting the alternator undesirably depends somewhat on the system layout. Some vessels, for example, have a switch in the battery bank negative. In others the alternator always sees a battery, even if all switches are turned off.

4. Re what the VP MDI expects to see for the Reg-on. Would it be helpful to ask the alternator specialist if the alternator expects a constant voltage or a pulse on start up? I am unable to check this on the boat until the spring as she is laid up for the winter in Brittany, France.

From an alternator point of view, a short pulse is sufficient as the alternator can self-supply once it has been started. However, I have no idea what 'smart stuff' VP put in the MDI. Maybe the MDI simply supplies battery voltage the whole time the engine runs and doesn't care whatsoever. Maybe it checks voltage and current to see whether there's indeed an alternator attached.

[James HR40]

Originally Posted by Stu Jackson

I agree, and welcome.

Don't know if you know of Maine Sail, a frequent contributor here and on other boating forums, is a quality boat electrical systems installer, who has developed a very good website of his own: www.marinehowto.com.

He has a number of articles on alternators and regulators. Most external regulators we see on boating forums relate to the Balmar versions, yours is or will be new to many of us (except those who have them). IIRC, he wrote up one of changing from internal to external - I know, the opposite of what you are doing, but it may help.

Here's a link:

Converting a Leece Neville Alternator to External Regulation by Maine Sail
http://c34.org/bbs/index.php/topic,4879.0.html

He also had an older website, pbase, and contributed on sbo.com. Here are some from those:
How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail): http://forums.sbo.sailboatowners.com...d.php?t=125392

Alternators & Voltage Sensing (by Maine Sail):http://www.pbase.com/mainecruising/r...oltage_sensing


I suggest looking around there for more info.

Maine Sail has recently had a stroke and is hopefully recovering, and so can't answer here or on his own site.

Good luck.

Thanks Stu. Looks like there is a mine of information on Maine Sail's site

[Stu Jackson]

Originally Posted by James HR40

Thanks Stu. Looks like there is a mine of information on Maine Sail's site

James, there is. In addition, MS has written quite a bit on sbo.com as a Featured Contributor.


I have saved a lot of links in this thread I created that has a ton of other material but might be helpful to you. It is a long winter after all.


Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html