Good grief, it never ends. Alternator upgrade needed.

[bcboomer]

I don't know what mounting system you have or how much space you have.
If you have the space and mounting option then a truck/ambulance/bus alternator will give you lots of juice and last almost forever.

I don't have the space or mount so I bought a brushless 200 amp alternator from All-Tek Industrial for $320 CAD. It came with a serpentine pulley and a local machine shop fabricated a couple of pulleys for my crankshaft and water pump for about 1/3 of the price of a kit. They also modified my mount and the alternator case to fit. Slightly bigger than the old Motorola but fits.

I'm charging 4 Firefly G31s and expect to be able to use the full 200 amps for long enough to be worthwhile.

Now I just need to decide what regulator to add, and rewire, and pull out the outdated stuff, etc, etc.

[Mike Banks]

If you were happy with your alternator up unto the time it went on strike--you probably need to replace the regulator or the slip ring brushes, but one of the diodes has died as like as not.

While you have it stripped, clean it thoroughly and replace the slip ring brushes and bearings. It should not cost more than a hundred dollars or so. While it is stripped, you might also consider and external regulator--mounted high in the engine compartment. Some are adjustable, most pre-set. They are easier to replace that way. wiring diagram comes with most regulators--I had a BOSCH one with its own little aluminium heat-sink housing nicely clear-varnished.

[thereefgeek]

We recently upgraded our old 110a Leece-Neville on our 4-108 after it took a dump trying to charge our 500 Ah LiFePo house bank. Our batteries will take as much charge as you can throw at it, and the internally regulated alternator simply overheated and fried itself to death. We went with a 150 Balmar, MC-614 charge controller and serp pulley kit from Balmar (wish we'd gotten the pulleys from TAD instead). The Balmar kit had some fit-up issues and was not a plug-&-play install, but got the issues resolved and had to weld up a new alt bracket to get the pulleys to line up correctly as well as a little machine work on the lower pulley to make it fit the crankshaft. I heard from another Perkins 4-108 owner after the fact that his pulley kit from TAD fit perfectly.

You may not need a high output alternator now with your small FLA battery bank, but consider that if you ever plan to upgrade or expand your storage capacity, you'll be glad you did.

We made a multi-part video series on the install and upgrade process here:

https://www.youtube.com/watch?v=TFA37Hrz9is&t=54s

https://www.youtube.com/watch?v=o6tEVsAcNBM

https://www.youtube.com/watch?v=AgBpghTwDmo

[morgan38]

I have had good performance with a similar battery bank using a Leese - Neville 8MR 105A marine alternator. I also have a Perkins 4-108. An adaptor is available for the 2 in. mount. Has an integral single stage regulator. Which has been sufficient for my needs. (I have adequate solar.) They make alternators for Balmar, but are a fraction of the price. I paid $215 for with the adapter, pulley, shipping' and tax a while back. I don't think the price has gone up a lot.

See the Compass Marine article on converting to an exterior regulator, and discussion on the alternator. https://pbase.com/mainecruising/alternator_conversion

[sailandbail]

Wow, really great info. This is the direction that I'd really like to go, but dang, it starts getting pricey! Thanks for documenting all of this.

[Singularity]

Originally Posted by thereefgeek

.... We went with a 150 Balmar, MC-614 charge controller and serp pulley kit from Balmar (wish we'd gotten the pulleys from TAD instead)...I heard from another Perkins 4-108 owner after the fact that his pulley kit from TAD fit perfectly...

Great post/videos...I need to do similar soon. Would point on that maybe TAD isn't the cheapest.

FWIW there was a thread on "who makes TAD/SW pulleys":
http://www.cruisersforum.com/forums/...ys-162564.html

Partial quote from EVM1024 in the linked thread:
"I bought the pulleys from SW Diesel for a good price. The kit from TAD has the same pulleys but costs more by a bit. However, the TAD kit comes with the alternator spacer that is required to move the alternator 3/4" forward.

Being a DIY kind of guy (as are so many sailors) I decided to make one myself. TAD would want $90 for the spacer if they had any to sell."

[Singularity]

Originally Posted by thereefgeek

a little machine work on the lower pulley to make it fit the crankshaft.

After watching the video attaching the pulleys I was wondering...is there any chance that the new crankshaft pulley was intended to be a shrink fit? Where you are to heat up the pulley (hot oil, oven, torch, etc) to open the hole before slapping it on?

Sometimes this actually makes a bit of a difference from an engineering standpoint, but not sure if it's important here.

[lewisa]

I have used a 100 Amp Balmar (912-100) on my 4-108 charging pairs of 6V Trojan T-105's (225 AH per bank) for 15 years without any problem I have the Balmar ARS-4 regulator). My single belt pulley works well. Although expensive, I like the fact that everything connects easily and unambiguously, including temp sensors. I am not a heavy energy user, so 100 amps is more than enough; initial charge rates are more commonly in the 50 amp range.

The serpentine belt conversion is attractive and I may go that route if I have several hundred dollars burning a hole in my pocket.

[john61ct]

Originally Posted by sailandbail

Wow, really great info. This is the direction that I'd really like to go, but dang, it starts getting pricey! Thanks for documenting all of this.

You'll be happy absorbing, as stated several times by many, all this higher-amp upgrade talk is irrelevant to your use case.

When you decide to upgrade your **battery bank** to a chemistry that can accept a high current rate, revisit the topic.

It is possible to put in a bank that will burn out even a 200A alternator; the key then becomes a VR or DCDC charger that helps limit the current demanded of the alt.

But your current bank can't even accept what your current alt puts out, so you can save a lot of money just troubleshooting within your current amps output range.

[Bill O]

Originally Posted by john61ct

You'll be happy absorbing, as stated several times by many, all this higher-amp upgrade talk is irrelevant to your use case.

When you decide to upgrade your **battery bank** to a chemistry that can accept a high current rate, revisit the topic.

It is possible to put in a bank that will burn out even a 200A alternator; the key then becomes a VR or DCDC charger that helps limit the current demanded of the alt.

But your current bank can't even accept what your current alt puts out, so you can save a lot of money just troubleshooting within your current amps output range.

John,
As usual, excellent advice. I agree its been said many time, but I'm thinking the OP wants to spend a good chunk of change rather than fix what they have. In this case, bigger is not better (alternator) for the current battery set up.


Bill O.

[Matt Johnson]

Originally Posted by sailandbail

I currently have four 115ah 6 volt "golf cart" batteries.

Are you sure about this? I'm not expert on golf carts, but I don't think I've seen 6 volts with that low Ah. 230Ah is a pretty common golf cart battery capacity.... You're not dividing the 230Ah rating for 6 volt are you? When put in series to make 12v, you are doubling voltage, but capacity stays the same. Your bank may be 460Ah at 12v.

Matt

[GrowleyMonster]

Originally Posted by sailandbail

The alternator on my Perkins 4108 stopped producing a charge a couple days ago, about 2 weeks after I installed a new battery bank. It's the original alternator on the engine of my 1979 Cooper Sea Bird and had done an adequate job until now. I knew that the day would come that I'd need to take this plunge because power demands are higher than they were 40 years ago, so I'm ok with it (though it's not super exciting spending a bunch of $).

I just got off the phone with the folks at TAdiesel.com, specifically the Balmar specialist, who was incredibly helpful and friendly. They are the only ones I've spoken to so far because I've just started to do my research. They sell a kit that includes a 70 amp alternator, a regulator, temperature sensors, and a harness for $950. He mentioned that I could get an alternator with higher output if I planned on adding to my system down the line, but I'd need a serpentine pulley kit for a larger alternator which is another $675.

I'm a novice with this stuff and couldn't be more grateful that I've stumbled upon this site because it's already been an amazing, friendly resource in the couple weeks I've been here.


I currently have four 115ah 6 volt "golf cart" batteries.

My questions are:

-Would you go with Balmar?

-Is 70 amps sufficient if I added a couple more batteries in the future, or would I be completely limiting myself?

-Is an alternator something that is smart to buy new?


Thank you in advance for your input, I appreciate it so much. Luckily the joy of cruising still outweighs all of the work, time, and investment involved in keeping this vessel afloat.

Evan

You don't mean "215ah"? I have never seen a 115ah GC battery. That's a good economical setup. I don't think you will ever NEED to upgrade from 70a unless you run a good sized inverter for 110v appliances, but a serpentine belt is a sensible upgrade anyway. An alternator is something that it is good to have a spare of, BTW. Get a new one, and a rebuild for a spare, is what I would do. Get a spare regulator, too. Obviously a spare belt as well. Balmar is a good brand. The quote sounds just a little bit high. Well, ALL quotes sound just a little bit high, to me LOL! IMHO original alternators on these engines are inadequate for the use we put them through these days.


Have you considered adding a couple of solar panels, for topping and float charging? Running your main engine is fine for bulk charging, maybe absorption stage as well, but not for topping. Very inefficient. Where the diesel shines is the bulk charging phase. Unless you motor a lot, anyway.



I have a 4-107, BTW, and a serp belt and bigger alt is one of the upgrades I am planning, FWIW.

[thereefgeek]

Originally Posted by Singularity

Great post/videos...I need to do similar soon. Would point on that maybe TAD isn't the cheapest.

Yep, TAD WASN'T the cheapest. However, the time I spent d!ck!ng around welding my own custom alternator bracket to account for that 3/4" offset you mentioned above, as well as having to custom machine the lower pulley to a slightly larger diameter (0.003") to fit the crank shaft would've been money well spent in the long run by getting the kit from TAD rather than Balmar. And just to clarify, I have no monetary association with either of the aforementioned companies. I threw my money at Balmar and they choked the monkey (in my opinion).

Not to toss anyone under the bus, but another Youtube sailing couple contacted me regarding this exact same fit issue on their Westerbeke 30. Over the phone and through emails, he ended up doing the exact same thing I did to make his kit fit (Balmar kit, NOT TAD).

In the end, everything works great. Good belt alignment, excellent charging capacity, and a new 4-108 water pump with a pre-installed serpentine pulley. In my opinion, not a project for the less-than-diy-inclined. If your handy and can figure out minor discrepancies that play a big role in mechanical systems, then go for it.

[thereefgeek]

Originally Posted by Singularity

After watching the video attaching the pulleys I was wondering...is there any chance that the new crankshaft pulley was intended to be a shrink fit? Where you are to heat up the pulley (hot oil, oven, torch, etc) to open the hole before slapping it on?

Sometimes this actually makes a bit of a difference from an engineering standpoint, but not sure if it's important here.

No, no shrink fit. If you bothered to watch the video, you can see that once I cracked the 150 ft/lb torque crankshaft bolt, the factory pulley slid off like butter. It's a machining tolerance issue that I had with the Balmar kit on the lower serpentine pulley (that others have had as well). Once I machined the pulley i.d. to match the shaft o.d. it all came together perfectly...

...except that I STILL had to weld some metal onto, and severely modify my Perkins factory alternator bracket to make it work.

[bcboomer]

If you have a small machine shop close by you can have pulleys machined that won't require any shimming for a lot less money.