doubling up an alternator pulley belt

[simon_sluggett]

I have fitted a sterling charge boost regulator to my yanmar alternator and it charges great but it now also eats up the rubber belts like crazy. Has anyone tried doubling up the pulleys and belts to overcome this? Was it successful? Where can I source some double vee pulleys
Ta Simon

 

[Talbot]

seem to recall a recommendation to change over to the v notched belts, but cant remember if that requires a new pulley shape.

 

[Birdseye]

are you using yanmar belts or are you using ones from the auto parts shop. these are a different shape, and they rapidly bottom on the pulley and start to slip. dont ask me how I know that !

you can get a correctly shaped alternative belt from fenner power transmissions.

the other possibility is that your yanmar pulley (mine was a flimsy pressed steel jobbie) is distorted / loose. check carefully.

the yanmar system is sized to drive the alternator at full output which is exactly what you are doing with the regulator. all that has changed is that you reach full output more often so the belt system should still work without probs using the correct belt and pulley.

 

[SvenglishTommy]

Are you sure you have enough tension on the belt? It could be slipping causing extra wear.

As birdseye says, the belt should be fine at full output if you are using the standard alternator, installing double belts and pullies seems a little drastic.

 

[Avocet]

If none of the above work, you might be better going to a multiple-ribbed belt ("Poly V") belt rather than trying to double the single V belts. They are never exactly the same length and therefore they never quite share the power evenly. Obviously, there are such installations about but modern cars where alternators are much bigger and hungrier tend to use the latter sort. This will, of course, involve new pulleys too so it isn't cheap but it's probably te best long term solution. Gates used to have a free belt-sizing and calculating programme you could download off their website.

 

[Ships_Cat]

A single belt should drive your alternator - problem is usually mediocre quality belts, even the originals supplied with new pleasure engines.

I would personally try a Gates notched belt of required profile first, before getting into more complicated solutions, they have a good reputation with commercial users and throw little dust, etc.

As an example, our large service battery bank alternator is well over belted with 2 belts but even so when the boat was new they threw alot of dust/rubber and the standard Volvo Penta alternator belt did the same - a change to Gates belts tidied it up immediately.

John

 

[Robin]

Unless your batteries are knackered or you routinely run them very low even a smart regulator will not call for max alternator output and therefore maximum load and there shouldn't be a problem. We run 2 alternators with Adverc smart regulators off our Yanmar 4JHE 44hp, one is the Yanmar Hitachi one but the optional 90A version and the other a Lucas also 90A, each run large capacity separate battery banks and both run without problems on single belts. We never let batteries drop below 50% charge (12.4/12.5v rested and off charge is my action point) and the alternators usually never exceed 50A each even after startup. We do routinely change both belts each winter service and keep the old ones as spares (I have loads of spare ones therefore!) but our engineer says it really isn't necessary as they are both fine, I prefer not to have to change one at sea however so annual replacement it is.