Upgrade the alternator of a Volvo D2-55

[Ailatan]

The first and second version of the Volvo D2-55, series A and B came with a 60 A alternator, but the following versions (C, D, E and F) came with a 115 A alternator.

The difference is not only the alternator like the belt, the pulleys and the tensioner, but I don't know if the fixing point is also different.

Has anyone done this upgrade or can share a picture of his/her engine with the bigger alternator?

[IslandAlchemy]

You might be better off replacing the diode splitter with a Sterling A to B charger. Very easy to do, and will give you a better charge of the house batteries than upgrading the alternator.

I did this on my boat 10 years ago, and it's transformed the charging.

[Ailatan]

Thanks for the advice IslandAlchemy, that's interesting because changing the alternator was going to be the first step of a process where the second step was going to be changing the service battery to LiFe and installing a Sterling DC-DC charger.
Your idea was also considered but I thought it was better the DC-DC charger because it has the option to reverse charge the engine battery from the service battery

[elias]

Are there any owners that have used this alternator with an Orion DC DC 30amp charger on a lithium setup ? What is the actual charging rate of this setup (60amp alternator and Orion) ? Does it steadily gives 20-30amps ?

[Ailatan]

Definitely, swapping the alternator is not going to be straightforward.

The place where the D2-55 alternator attach to the engine has a "male" shape and is 50mm long, while the D2-55C and following models have a "female" shape and is 105mm long

[sy_Anniina]

You might also consider upgrading to a similar housing and belt pulley, but higher max amp spec alternator. This is what we did on our MD22L-B https://bavariayacht.org/forum/index.php/topic,3783

For most of the time, the real-world output will be well below 100A, allowing single high-quality V-belt to be able to manage the load. Of course this would depend on your battery charge-in capacity. We see close to 100A when domestic bank is "empty" (=50%) and bow thruster is engaged - which is only a momentary load.

BR,

Tommi - s/y Anniina

[tiger79]

My last boat, a Hallberg-Rassy 352, had a VP 2003T engine with a 50A alternator.  I changed the house bank to 660Ah, so obviously needed more charging.  The solution I finally decided on was to buy the VP extra alternator bracket and fit a second alternator.  Initially, I fitted a 130A alternator but this just ate the single V-belt, so I replaced it with a 90A alternator (which is about as much as you can reasonably drive with a single V-belt).  The system worked well for many years, and I had the added redundancy of a second alternator in the event of one of them failing.  I chose a Prestolite Leece-Neville alternator, as these have a really good output curve with lots of amps at lower revs.  I believe VP offer a second alternator bracket for the earlier D2-55 engines.

[Ailatan]

Thanks Tommy, a pity that your alternator is not available anymore because I have seen that our engines share the same alternator. So I will have to look for another supplier.
Did you experience any problems with the alarms of the Volvo panel or any issues with the belt?
Tiger79 I have just bought a couple of batteries with the same capacity as your HR, that's why my first step is to increase the Amp of the original alternator and, in a second stage, I'll fit a second one so I will have 200A in total

[tiger79]

Tiger79 I have just bought a couple of batteries with the same capacity as your HR, that's why my first step is to increase the Amp of the original alternator and, in a second stage, I'll fit a second one so I will have 200A in total

Bear in mind that the current output of an alternator is entirely dependent on the batteries' ability to accept the current.  So an alternator rated at 100A will rarely deliver 100A unless it's feeding a large battery bank which is in a state of low charge.  Also remember that max output is only achieved at max revs - this means higher revs than most boats will use at cruising speeds.  When I had a 90A alternator feeding a 660Ah battery bank, I rarely saw more than 60A actually going in to the batteries.

[Ailatan]

Thanks for the point Tiger79, just one question, you mentioned that you had a 660Ah battery bank but you didn't mention the technology: lead, AGM, LiFe.
I think that Life batteries accept a higher input current, but that's something to bear in mind

[sy_Anniina]

Hi Ailatan,

No issues so far with the belt - still running the same belt after - I guess.. - ~80 engine hours.

No issues with Volvo panel - but the MD22 is a "non-electronic tractor motor" - I see the tacho would be the only potential thing to show erronous readings, but even it works just perfectly.

No direct experience with this unit or supplier, but my 2sec ebay search found this item
https://www.ebay.com/itm/305354957066?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fyotfvv7ro6&sssrc=2047675&ssuid=loWNu-YKTIy&widget_ver=artemis&media=COPY

BR,

Tommi - s/y Anniina
 

[tiger79]

Thanks for the point Tiger79, just one question, you mentioned that you had a 660Ah battery bank but you didn't mention the technology: lead, AGM, LiFe.
I think that Life batteries accept a higher input current, but that's something to bear in mind

Lead acid.

[Ailatan]

No direct experience with this unit or supplier, but my 2sec ebay search found this item

Amazing!!!! Believe me, I have been searching for hours and I found others but I have to discard them for one reason or the other.
I think that the results that you get depend on the country where you are located. Otherwise I have no other explanation

[Ailatan]

Lead acid

The owner manual of my batteries says that the maximum charge current should be 100A.
As I have 2x320Ah, does it mean that maximum charge I should get from the alternator should be 200A?
Sorry because I was sick when the teacher explained that.

[sy_Anniina]

Lead acid

The owner manual of my batteries says that the maximum charge current should be 100A.
As I have 2x320Ah, does it mean that maximum charge I should get from the alternator should be 200A?

100A would be maximum recommended charge current per battery - so Your max recommended charge current would be 200A....but...

• there is no specific need to reach this max current, it is perfectly ok to charge at max 100A
• the battery is likely able to absorb the max current only for a short time when almost completely empty - which you want to avoid to maintain battery life
• 200A alternator and associated cabling, controllers etc would be eyewatering expensive and cumbersome to install
• your mains charger is most likely well below 100A anyway (say 20-30A)- and the batteries are happy with that as well

BR,

Tommi - s/y Anniina

[tiger79]

The owner manual of my batteries says that the maximum charge current should be 100A.
As I have 2x320Ah, does it mean that maximum charge I should get from the alternator should be 200A?

Technically, yes.  But although you haven't said so I'm guessing these are lithium batteries, which can be tricky to charge.  They have a built-in battery management system (BMS) and in certain circumstances the BMS can disconnect the battery from the terminals causing some chargers to fail to work.  If the BMS disconnects while you are charging from the alternator, your alternator could be damaged.  I'd suggest you research this before doing anything.

[Happysailor]

Also consider the wiring which is applied in your boat. Increase from 100A to 200A will increase the heat in the wiring which is designed to 100A.
Charging at higher currents may cause fire hazards!

Don’t play around with these kind of things and seek for professional advice, to avoid huge problems with just modifying the installation without looking at it as a whole.

[Ailatan]

Thanks Tiger79 and Happysailor, I am professionally advised with the installation but the "professional" doesn't know all the options in the market and I am trying to help with that part

[jeffatoms2]

We started (not completed yet) this upgrade on an MD22L-B last year (summer 2023).  The upgrade was from the stock Volvo alternator that never produced more than 15 amps to a 120 amp Balmar 621 including new serpentine belt and pullies.  The kit came with a "universal" mounting bracket that wasn't quite universal enough to fit it to our engine.  We fabricated a bracket at work and the install went remarkably smoothly, except we assumed the alignment on the serpentine belt was close enough.  It wasn't and we shredded the first belt on the exit from our harbor.  We have popped a few more belts since but the good news is that I can change them like a Formula 1 race pit crew member in about 2 minutes.

A year later we continue to mess with alignment, adding and removing shims.  Turns out this is critical
I believe we have it now and what a difference it makes, regularly producing 80-100 amps at relatively low RPMs.

We still have on the list of tasks:
1. Add battery temp sensors
2. Recalibrate tachometer
3. Add an alternator delay at engine start-up to delay the load by 30 seconds or so

I worry about side loading the crank shaft a bit too much but the next task will be to find the adjustment screw to get the tachometer in synch.

So far it has been a great upgrade

Good luck!

[Ailatan]

Thanks Jeffatoms2, that's a good input because I was thinking that Balmar was my last and expensive option if I pretend to find something bigger than 100A with only one Alternator.
I saw that you need to buy the pulley conversion kit 48-VSP-D2-A (this is for a D2-55). Is that the kit that you mentioned?
They also recommend a Tachometer Signal Stabilizer 15-TSS. Did you also buy that?
My main concern is that being such an expensive piece of equipment it's so complicated to make it works properly.

[elias]

Am I the only get stressed for 100amp constant current passing around a hot engine room? Wouldn’t be preferable to wait an extra couple of hours on engine with let’s say 50amps charging than 100?

[jeffatoms2]

Yes, we bought the alternator, the external regulator, the battery combiner, the pully kit, the smart Guage, shunt and Bluetooth sender and a universal arm. The tach seems to only need recalibration. 

Aside from having to fabricate a new, quick adjust mounting arm which added a couple of hours, it was a straight forward full weekend project to installing and the next weekend shimming.  Followed by a year of tweaking.  If I were to change anything it would be to get the Victron electronic gauge.

The key is the external regulator manages the load (the brains!).  It only produces full output when my bank needs it.  We moved the start battery to the bulkhead above the engine behind the companionway stairs so that no additional heavy gauge wire pulling was needed.

Really the toughest part was convincing everyone at Balmar and their dealers that their fit guide was wrong and that the Prima and the MD22 Turbo as listed were the same engine block as the MD22L, which wasn't listed.

I have considered changing airflow in the engine bay to blow off more heat and to have it vent away from the cockpit; I've never liked that feature. The high amperage in the engine bay itself isn't really a concern.

[jeffatoms2]

Would I do anything different?  YES.

For starters, I would have purchased an external regulator and installed it on the existing OEM alternator that was rated for 60 amps.  Remember, i was typically getting 10-15 amps prior.  I would need it regardless so why not start with that simple, relatively  low-cost upgrade to see if it boosted the output to acceptable levels.  If that didn't work, only then would I go all in knowing what I know now.

[symphony2]

Am I the only get stressed for 100amp constant current passing around a hot engine room? Wouldn’t be preferable to wait an extra couple of hours on engine with let’s say 50amps charging than 100?

You really don't need that kind of output - batteries simply cannot absorb that in normal use. The reason for going up from the old 60A alternators to the current 115A is to get the charge larger banks need at lower rpm. The old also charged at a lower voltage and as jeffatoms says the usual mod was an external regulator to boost the voltage. These are now old hat because the new alternators don't need them. Even with lithium you need a way of controlling the charging current either through an external regulator or a limited DC/DC.

In cruising boats like ours, particularly in hot sunny climates like yours where you use solar to maintain charge you should never have flat batteries as you usually operate in the 60-90%+ SOC range so the engine really contributes little unless you do long distances under motor and consume a lot while you are doing it (running 240v items through an inverter for example).

The current is not the cause of the heat, that is from the engine and the alternator running hard

[elias]

I m not saying that the heat is caused by the amps but over time , corroded earths , loose cabling etc I don’t know how they will react in a hot engine room with 100amps. I m still sceptical, cause is an idea that comes and goes in my mind , of a bigger alternator