Alternator belt Slippage

[rgleason]

I think any alternator shroud for our Yanmar will have to be made of metal because the manifold is barely 3/4" away.

[pau-hana]

Hard to tell the sizes from your pics. My 32 hp Universal had a 3/8" belt to spin the water pump and alternator. Upgraded to Balmar 110A alternator and 3 step regulator and the belts would last for 4 months before stretching/squealing/glazing. I replaced it with a 1/2" belt. (of course a Gates green) The belt sits flush in the alt sheave and rides a bit proud on the crank and water pump sheave. I havent touched it in 5 seasons now. Never slips/squeals or glazes so far. I had to go up in length a bit since it sits Higher in the engine sheaves. A good shop will have the measuring thingy to load the old belt in and see that the length matches the wider belt.

You shouldnt have to worry about limiting output or taking a battery out of the loop. That's defeating the purpose of faster charging....

[lateral]

Originally Posted by akopac

When I made ours I didn’t have access to Ebay. But what the heck

https://www.ebay.com/sch/i.html?_fro...round&_sacat=0

Yep, thats the way I went, being on a budget and finding that buying so called "marine stuff" didn't necessarily equate to value for money.
Bonus is, that alternator is super easy to convert to externally regulated
and force feed external air into back of it.
Its a no brainer to bolt straight up. (A coupla mm off a boss and some shims.
So cost effective i have a drop in back up if necessary. 5yrs on the first.
Goal is to run two, and convert to FF's. Spend money where it gets value.
Good bye to PSOC.

I looked at water cooled as in ex Audi, but turns out they are not as reliable as brushed.

[belizesailor]

Another contributing factor to alignment and thus belt wear/slippage is the alignment of the alternator shaft itself. Worn bearings can cause the shaft to be misaligned...if everything else seems right, check the alternator shaft/bearings.

Derating the alternator wont fix this issue, though it may reduce it. So, if you derate by adjusting the external regulator or modifying the alternator (adding resistors) and you've still got a problem then check this.


And, never pay for a "marine" alternator, they are just a rip off. In most cases you can find exactly the same alternator at an autoparts store for a fraction of the cost...exactly the same.

[admiral 31]

After looking at the alternator shrouds, https://www.ebay.com/sch/i.html?_fro...roud&_osacat=0

It would suggest that the metal 'fan' fitted behind the belt pulley at the front of the alternator would suck or pull air through the alternator via the shroud

As opposed to blowing air through the alternator from behind,

which would be in direct opposition to a road vehicle type alternator set up which normally faces forward with the fan in front, which sort of says push!

I must confess I am totally confused as to which way the alternator fan actually pulls/pushes air?

I would not like to build an electric fan cooling system for the alternator which worked against the inbuilt fan.

Can anyone help please?

[rgleason]

Most alternators pull air in with the fan.

The SI28 Delco has a rear fan that also pulls air in, both front and back fans have outlets in the body

It is best to find the alt's documentation.

[wsmurdoch]

Older style automobile alternators had an external fan behind the drive pulley that sucked air in from the back and discharged it at the front. The entering air passed over the diodes and voltage regulator then over the stator and rotor. This style alternator had a case without holes in the middle part of the case. To improve cooling and reduce noise, the general design evolved in the 90s to a dual internal fan design. One fan sucked air in from the front discharging it in the middle cooling the stator and rotor. A second fan sucked air in from the back also discharging it in the middle cooling the diodes and regulator as well as the stator and rotor. Alternators of this design have holes throughout the case and no external fan.

[rgleason]

Has anyone tried getting or making better fans than the pressed square bent fans that come standard with many alts?

How much improvement in airflow is possible?

Is there a good improved replacement fan for the Delco SI28?

[coopec43]

I have often read from multiple sources that 90/100A is the maximum you can go with a single groove pulley.


I went to a 24V 60A x2 groove pulley but that wasn't easy. If I did it again I would use a serpentine belt as they have here. "Not your fathers Perkins"

https://www.enginebuildermag.com/201...-4-108-engine/

[wingssail]

Originally Posted by coopec43

I have often read from multiple sources that 90/100A is the maximum you can go with a single groove pulley.


I went to a 24V 60A x2 groove pulley but that wasn't easy. If I did it again I would use a serpentine belt as they have here. "Not your fathers Perkins"

https://www.enginebuildermag.com/201...-4-108-engine/

Nice Paint job, too bad it doesn't like a real boat. My alternator outputs 130 amps at 12v on a single belt. Since I reduced the alt pully so the rpm is higher, and got excellent alignment of all the pulleys and the belt, I have had no problem with belt wear.

Don't believe everything you read about what you "have to" have.

[Sternwake]

I'm a bit of an electric fan enthusiast, and am impressed with the impeller and case designs of Noctua, Delta, Nidec and SanyoDeki computer fans, and how much those blade designs vary, depending on intended application.

Looking at alternator fans, I am not impressed with stamped steel or cast aluminum designs, with 90 degree bent blades, no thickness flow/foil and seemingly little thought into maximizing airflow without a noise generated being a significant limiting factor.

Alternator fans are a brute force centrifugal fan exhausting air in a 360 degree outflow, as opposed to pushing it through a restriction directly in front of fan blades.

Every axial fan I have experimented with, does far better pushing air through a restriction rather than trying to pull it through one yet all alternator fans all seem to be pullers with radial outflow that do not have the same ability to take potential degree of advantage of the Coanda effect

Still, I believe there has to be tremendous room for improvement regarding alternator fans, whether dual internal or single external, even if it is not production friendly and adds some danger or fragility with sharper trailing and leading edges.

Seems with alternators being 50 to 60% efficient, and with their efficiency dropping with more heat generated, there would seem to be significant room for improvement.

But perhaps that level of improvement is just not profitable, and the mindset of it having worked 'just fine for 50 years' .... Why upset the applecart.

I'd very much enjoy having the tools and skills to design manufacture and test alternator fan designs.
Seems this would already have been done.

Perhaps it has been, and has been found to be lacking in enough benefit found to go further.

I recently contacted Leece Neville about a fan designed for CCW rotation instead of CW. They said the cooling difference between bidirectional and CW directional fan is 'minimal ' and no CCW fans for the specific alternator exist. There are belt limitations which will force regulator to keep the alternator well away from its max rating(320 amps), but I'd be happier with a CCW designed fan rather than a Bidirectional one.

If there were not belt limitations, I'd certainly be ducting cool air to its backside, and a powerful fan would be force feeding it.

If it were my boat it would get one regardless, as there is plenty of room for it, and presumably I'd have enough money to satisfy my airflow urges

[coopec43]

Originally Posted by wingssail

Nice Paint job, too bad it doesn't like a real boat. My alternator outputs 130 amps at 12v on a single belt. Since I reduced the alt pully so the rpm is higher, and got excellent alignment of all the pulleys and the belt, I have had no problem with belt wear.

Don't believe everything you read about what you "have to" have.

Your post leaves me a bit confused

"Nice Paint job,too bad it doesn't like a real boat."

Sorry! Can you explain?


"Don't believe everything you read about what you "have to" have".

Of course not but when it is a reputable source I don't have a problem.

(There's a lot of dubious comments from people who think they know on these forums too )


https://www.tadiesels.com/serpentine_4108.html

[coopec43]

Originally Posted by wingssail

My alternator outputs 130 amps at 12v on a single belt.

Don't believe everything you read about what you "have to" have.

Has your alternator actually charged at 130A?

Do you have solar panels?

[s/v Jedi]

I had 3 alternators on my Yanmar 4LH-HTE engine: the standard Hitachi plus two big frame 225A each Lestec Brute alternators. These beasts had a single V-belt each and I regularly charged batteries at 375A so more than 180A each.

Dashew got that working by increasing pulley diameter and having 180 degree engagement between pulleys and belt. I still had belt dust but good belts lasted for many years.

Getting rid of all of that now. Solar will be the main source and these three alternators will be replaced with a single Balmar 170A plus serpentine pulley kit. It just received all the new gear from Rod Collins, MarineHowto.com

BTW, the new alternator is 12V, with Balmar 712 regulator and connected to two Odyssey PC2150 AGM batteries (engine/genset starting plus general 12V use) plus two DC-DC converters that charge the Lithium house bank. This prevents blowing up diodes when BMS switches lithium banks offline.

[coopec43]

Well here is a 150A alternator with single groove. (See thumbnail)

I guess if you can get enough wrap you'd get away with it but with the standard Perkins set-up (see above) they told me it wouldn't work. What would the wrap be? Not much more than 90°? (I couldn't have increased the size of the alternator pulley anyway)

Just looked at this thread and they confirm what I have always come to accept.
https://forums.lr4x4.com/topic/58347...-v-alternator/