Grandchildren, fraying v-belts... MC-614 to the rescue?

[john61ct]

No, normal X-groove belt, GIYF

"micro-V" is what Gates calls them

[passthetuna]

Coming from someone who took aircraft alternator troubleshooting calls for 20 plus years. If it's aligned and nothing is moving under load, belts last a long time. Low rpm and heavy loads really tax that 3/8" belt. If the pulley grooves are mis-sized, or worn that belt may be riding to low in the groove. The sidewalls of the V-Belt and sidewalls of the pulleys are meant to carry the load. Not the base of the V, or bottom of the pulley. Belt dust over the short term - hours - means something ain't right.
1. carry an extra belt- their cheap
2. shed loads
3. check your mounting brackets for play
4. check your pulleys for size/wear
5. make sure the alternator doesn't have a bearing shelling out
6. make sure the wiring to and from the alternator are all good.

A poor ground , or lose output wire will play havoc with an otherwise good system.

[a64pilot]

Originally Posted by john61ct

If you are actually producing anywhere like 100A for any period of time a single vee belt simply won't cut it, no matter if Gates, nor however well tensioned and aligned.

It's just not designed for that level of torque.

Serpentine, 6-8 groove is better than just doubling up on the vee style.

No, he is right, aircraft or not really much else except maybe an RV will pull 100 amps continuously like a boat can.
My stock 80 amp alternator ate belts and dust was everywhere, the dust of course goes right through the gravel catcher air filter Yanmar fits and I didn't like my engine eating rubber dust.
Now I have a 125 amp with belt manager set to zero and a serpentine kit, run the belt a little loose to be kind to bearings and it doesn't slip, not even a little bit.

[john61ct]

The problem can show up very dramatically when replacing a stock FLA bank with higher CAR chemistries like quality AGM, or even more so LFP.

Standard VRs can just keep pumping full field current until the Alt blows up.

In that sense weak belts could be considered a safety feature 8-)

[Kerry1]

Originally Posted by Cheechako

Yes.. too good a regulator on a single belt 100 amp can be problematic. I had a 100 amp on a Yanmar, I had two regulators available. The Next Step regulator would eat belts super fast.. too fast to use. The Balmar mk4 wouldn't so I had to use it, but it didn't fill the batteries near as fast. Have at least one backup belt. Green Stripe or Dayco Cog are good.

Interesting discussion. When we were fairly new to our current boat, we became mindful of giving our auxilary engine a good work out every now and then (diesels are supposed to thrive on work) So on leaving our anchorage one lovely calm morning we opened her up to near max operating revs. Bad move. Because our batteries were down, (not to mention also a more than a little sick) our Next Step regulator rose to the occasion and demanded all the amps it could from our alternator. Within minutes our engine room filled with smoke and an acrid smell issued forth from our now dead alternator. (Luckily for us it didn't curtail our trip as we still had the standard issue alternator on another belt.) I also notice that there is a lot of belt wear on the alternator regulated by our Next Step, which fits in nicely with what you are saying. Belt tension is always an issue with that set up, so am interested in the serpentine set up.

As for the other guy concerned about not getting his serpentine set up before the added loads on his charging system. Perhaps a simple solution will suffice. Just don't operate your engine at high revs until the charging system has more gradually recovered battery amps. The alternator can't be made to work hard by the regulator if the speed of the engine is not there to match requirements. Sure it takes longer to charge, more engine hours necessary, more deisel, more annoying noise, but is much gentler on all systems, regulator, alternator, belt, (battery?) and also You.

If we are out for more than a weekend I am now always mindful of the speed of our engine versus the depth of discharge on our batteries and regularly check the charging amps before amping up the engine revs. Sometimes the turtle does win the race.

[john61ct]

Or just use a VR like MC-614 that derates field current as needed.

I tend to prefer "systemic" solutions rather than relying on my presence of mind.

[GordMay]

Greetings and welcome aboard the CF, passthetuna.

[oleman]

Originally Posted by john61ct

If you are actually producing anywhere like 100A for any period of time a single vee belt simply won't cut it, no matter if Gates, nor however well tensioned and aligned.

It's just not designed for that level of torque.

Serpentine, 6-8 groove is better than just doubling up on the vee style.

Another issue is a pully with a too small diameter. The larger the diameter the engine and alternator pullies are the less belt wear you will have.
So two good quality belts and larger diameters are a real fix and far less of a problem the the flat-belt spring loaded and static idlers.
Our old 2 stroke detroit diesel has a very large dual belt drive for the front alternator. We run an industrial alternator, no belt issues the rear alternator is directly driven from the balance shaft with a speed-up gear box.
No place for this engine in a smaller vessel but it is really the way to go.

[john61ct]

Actually the relative pulley diameters determines the relationship between alt rpm and engine rpm.

I had a conversion van where I wanted my alt to produce higher amps at high idle, but that meant going down in size, and definitely needed a pro to ensure I wasn't pushing the alt too fast at highway cruising. Petrol engines have a greater rpm range of course.

Ended up getting a custom-built high output alt on that build as well.

For what it's worth, main point it's not usually an option to change one pulley without the other, just to reduce belt wear.

[a64pilot]

However, I am of the opinion that to a huge extent Alternator output once you solve the belt problem is driven by cooling, spinning one faster will allow for more power with less field current and will of course spin the fans faster, meaning more cooling air.
I am of the opinion that our marine alternators are underdriven, same pulley ratios used for 6000 RPM cars etc., and it would be beneficial to turn them faster.

[four winds]

Fairly sure oleman wasn't referring to a change in relative pulley diameters.

Rather that if both pulleys are a larger diameter, same ratio, they will have a longer contact area with the belt. Spreading the load and reducing wear.

[a64pilot]

I'd bet he meant increase the pulley on the alternator.
Be tough I think to find a bigger pulley for the engine side without making one, and that is tough too.
On my 4JHE, I don't think there is much room on the engine to make a whole lot of difference

[hellosailor]

Belt manager will reduce the loading on the belt as promised. But that's still really a kludge. If the pulleys are aligned properly (and yes, it can be torture trying to get a proper straight-edge in there to check) and the belt profile is correct (because there are different "V" profiles, and the kids getting minimum wage in the auto shop have no idea about that) and the belt TENSION is correct (yes, you can still buy tension gauges, much easier than all the measuring deflection routines, and proper tension ensures longer bearing life) then the only question would be how old the belt is.
All the folks who make premium belts (I'd only buy Gates, Goodyear, or similar US brand names in the US) say that after five years, the rubber deteriorates and needs to be replaced anyhow. So if you've got an older belt...that could be the problem. Get a spare and replace it. Or have that serpentine/ribbed kit shipped out via express.

100A alternator on a v-belt is marginal, btw. The ribbed belt will be the better long term solution.

[four winds]

Originally Posted by a64pilot

I'd bet he meant increase the pulley on the alternator.
Be tough I think to find a bigger pulley for the engine side without making one, and that is tough too.
On my 4JHE, I don't think there is much room on the engine to make a whole lot of difference

Except he said, " the larger the engine and alternator pulleys are the less wear there will be." To me, possibly meaning by design from the factory. A reference to his old two strokes maybe.

Agree about sourcing a crank pulley after the fact.

Also using off the self auto alt designs by small auxillary diesel builders limits possibilities.

[Frankly]

Over 20 years and two sailboats I have used a 70 amp small case Balmar (feeding 4 GC batteries) and a 100 amp Balmar feeding 6 GC batteries. Both set ups have 1/2" belts and Balmar 612 regulators. When those batteries were down I got dusting and was tightening almost every other day. I aligned belts until I was blue in the face (belt selection does make a difference Top Cog Gold and Vextran worked best for me). Finally added a toggle switch to short out the alt input temperature and normally run on half output. Everybody is happy (engine, alternator, belt, and captain). If I start getting behind the power curve (too much sailing or sitting) I flip the switch to full power and we load her up but the alt is hot, the belt is wearing, and the Yanmar starts running a little warmer. Stressing everything a little harder, but all in all worked out OK. Adding some solar this Winter just for the He** of it.