Alternator belt Slippage

[charliehows]

Dont know if removing a batt. will reduce loading but what i do know is this; the first symptom of a worn out fanbelt is screeching; second is it breaks. My alt. drive belt started making noise awhile ago, tried tightening it, no good, replaced it (bought 2 new belts, always keep a spare, possibly the dumbest, cheapest reason to be stuck in the middle of nowhere without an engine); noise stopped, no further problem.

[Jim Cate]

A possible cure that will offend the purists: use some spray on "belt grip" compound. This stuff is a tacky, sticky spray, applied to the running belt, that will significantly increase the power transmission capability of a v belt. It solved a perennial squealing and slipping problem we had in our previous boat where we were driving a Lestec 150 amp alternator with a tiny diameter pulley and a single half inch v belt (Gates greenie).

Not very sophisticated, but quite inexpensive and... it worked for me!

Jim

[CassidyNZ]

Make sure the belt is not bottoming out in any one of the pulleys. No need to assume it’s the alternator that is squealing, if one of the other pulleys are allowing the belt to reach the land at the bottom of the V, it will squeal.

Also as someone else noted, the belt in your pic is too long or worn out. No way you can get tension on a belt when at the end of the travel on the adjustment arm. And the belt doesn’t need to be bar-tight either.

There is no way that a fit belt correctly adjusted will squeal turning a 100A alternator. I have a standard A section belt driving 180A when the house bank is down - no squeal.

[Richard Kollmann]

If either pulley crankshaft or alternator does not have belt contact of 120 degrees or more belt will slip. This is sometimes the case on Yanmar engines where water pumps and alternator are driven off the same belt. Solution if belt contact is not enough is to lower the bulk charge voltage.

[john61ct]

Bulk (CC) stage it's the battery that controls voltage anyway, it's the Absorb setpoint that gets held by the VR possibly for hours once the CV setpoint is reached.

OP does not even know if VR is adjustable, nor if it drops output to a lower Float voltage.

Voltage setpoint needs to match the needs of the battery anyway, if there's no DCDC charger in between.

[kenbo]

I think we're over thinking this a bit. The alternator in the photo appears to be a lower amperage Hitachi based on the size of the stator stack visible between the DE case and SRE case. It's not squealing because it's being overdriven, the squeal is because the belt is too long/wrong size/glazed or all of the above.

[CassidyNZ]

Originally Posted by kenbo

I think we're over thinking this a bit. The alternator in the photo appears to be a lower amperage Hitachi based on the size of the stator stack visible between the DE case and SRE case. It's not squealing because it's being overdriven, the squeal is because the belt is too long/wrong size/glazed or all of the above.

I agree. Renew the belt, adjust correctly, come back to this thread if that doesn’t work

[wsmurdoch]

Originally Posted by Jim Cate

A possible cure that will offend the purists: use some spray on "belt grip" compound. This stuff is a tacky, sticky spray, applied to the running belt, that will significantly increase the power transmission capability of a v belt. It solved a perennial squealing and slipping problem we had in our previous boat where we were driving a Lestec 150 amp alternator with a tiny diameter pulley and a single half inch v belt (Gates greenie).

Not very sophisticated, but quite inexpensive and... it worked for me!

Jim

...and if you spray the belt and the noise does not go away, it may not be the belt that is squealing. ...something else?

Like starting fluid (ether), belt dressing is useful for diagnosing problems.

[Stu Jackson]

Originally Posted by Fiftybucks

Yes I have external regulator.. not sure it is adjustable yet.
my question is mostly
IF I disconnect batteries does it change the Alternator Load? maybe just battery switch from 1 or 2 instead of Both.

If this sentence "...IF I disconnect batteries does it change the Alternator Load?" is taken literally, do NOT disconnect the alternator output from the batteries IF the alternator is (still??? - in your case, perhaps) connected to a regulator. You will blow the diodes because the regulator is telling the alternator to produce and there's nowhere for that power to go.


Is that germane to your situation?


Disconnect from the regulator and you won't have to remove the AO from the batteries.

[rgleason]

Jim,

My father, an inventor, had a gooey stick which he called "belt dressing" which he used for years on many different kinds of belts. It works. - Perhaps I should try it.

Originally Posted by Jim Cate

A possible cure that will offend the purists: use some spray on "belt grip" compound. This stuff is a tacky, sticky spray, applied to the running belt, that will significantly increase the power transmission capability of a v belt. It solved a perennial squealing and slipping problem we had in our previous boat where we were driving a Lestec 150 amp alternator with a tiny diameter pulley and a single half inch v belt (Gates greenie).

Not very sophisticated, but quite inexpensive and... it worked for me!

Jim

[lateral]

I am running a 115A Alt with single green stripe on 464 Ahr bank.
Doesn't squeal at >100A, which sometimes take 5min-ish at constant voltage
diminishing current. Larger pulley on alt, carefully chosen to match correct belt
position. Forced air in middle of summer needed tho to stop smartcharger from ramping down. Custom tensioner of my own fabrication. 3GM30F. 3min change over.
Belts only last 50-100hrs tho as they are overloaded.

[john61ct]

Yes, conservative rule of thumb, go to multi-vee after 75-90A actual loads @12V nominal

100+ is a stretch

[wingssail]

Originally Posted by Fiftybucks

So jubilee. I can adjust the regulator down so the altternator request lower output?

Balmar regulators have, for many years, a "belt" adjustment which reduces the load so the belt can handle it. Operation Manuals | Balmar

BTW, we use a single belt with our Balmar 110amp alternator, have for many years, no problem. Make sure the belt is size correctly, the pulleys are aligned, and tension is correct.

[Stu Jackson]

Originally Posted by john61ct

Yes, conservative rule of thumb, go to multi-vee after 75-90A actual loads @12V nominal

100+ is a stretch

Just call me Stretch then.


100A Balmar MC-612 400 ah house bank see 50A output on 50% SOC bank, 3/8" belt single, properly tensioned.


In fact a larger alternator is preferable as long as you know what the output will be based on your battery bank's acceptance at a reasonable level of discharge, say 50%. Bigger alternator for the same load works less hard. Of course, within limits. But these are reasonable, tested in the real world equipment combinations, all done without serpentine belts, and they work.



And with an external regulator you can both dial it down with amp manager or SEM (small engine mode).


This is the reality of simply employing appropriate hardware. Many do.

[wingssail]

Originally Posted by Stu Jackson

100A Balmar MC-612 400 ah house bank see 50A output on 50% SOC bank, 3/8" belt single, properly tensioned.

Ooh! I like that answer.

In our case:
110A Balmar ARS-5 450 ah house bank see 100A output on 50% SOC bank, 3/8" belt single, properly tensioned, no squeal.

OP, your belt is too loose, in my opinion.