Alternator drive

[Sabre27Admin]

Peter OD
United Kingdom
50 Posts

Posted - 28/09/2009 : 15:44:48
Hi there Sabre sailors
I've just fitted a new alternator to my Volvo MD2B and would like to make larger(wider) or double up the pulley on the flywheel - does anyone have an idea how this is possible? I am trying to drive a 110 amp alternator and I need more ooomph in the belt really.
Regards to all.
Peter
joeschofield
19 Posts

Posted - 12/10/2009 : 19:58:41
Peter. Do you really need that much output or did you fit it because one "turned up"? I dunno what others are using but 110A is more than 55% greater output than I am using, and I have NEVER once been short of amps. I'd take a lot of convincing that I needed that much power, and as you have found it's not ideal to drive one that big with just one belt. If your MD2 alternator is driven off the flywheel you have a pretty impossible task.

sabre27
178 Posts

Posted - 12/10/2009 : 22:55:31
Hi Peter,

What capacity batteries have you on Sanda Isle? Unless you have 3 or 4 hundred amp hrs and are driving a washing machine every day, you won't use this capability anyway, so a good quality single belt kept at the right tension would probably be OK.

We have a 45amp alternator with a tight belt, charging 140 amp hrs of domestic batteries on Corsair, which run our 'Compressor driven' fridge all the time we are on board, all the lights just like at home, an Eberspacher from now on until Christmas and all the other goodies! We control the charging regime with an 'Adverc' for the last 25yrs or more, no problem.

The single drive belt on our Yanmar 2GM20 is now fifteen years old! The engine runs approx 150 hours a year. We are 8 miles to the open sea from our mooring.

Paul Howard. S27OA Technical Officer.

Peter OD
United Kingdom
50 Posts

Posted - 13/10/2009 : 09:04:18
Hi there

Thanks for your replies. The (automotive) alternator that was on Sanda Isle when I bought her had two lugs rather than one and was installed rather badly. The inevitable happened and a lug broke off; I was already considering the Adverc charge controller and decided to take their advice. I bought alternator and system from Adverc (for whom I have nothing but praise) and at the last minute a 110amp device was substituted for the 90amp one ordered (at no extra charge, but rather because they were out of stock).

I have installed everything and it is running just fine - I am more than pleased. However the pedantic perfectionist in me desires to have a drive belt and two pulleys that actually match, and clearly a 13 mill belt will be better than a 10 mill one.

The answer, I have concluded since my original post, is to remove the pulley which is bolted to the flywheel take it to an engineer (of whom there is no shortage locally) and let him sort it out for me! The original is surely only fabricated steel anyway. I'll let you know if it all ends in tears!

Happy laying up days

Peter

sabre27
178 Posts

Posted - 13/10/2009 : 22:37:55
Hi Peter
You are going down the right road with the engineer and the Adverc. We did that with our original Yanmar PMX 8 which had a dynastart. Made a new bolt on drive pully for the flywheel and ran a Lucas 35 amp alternator off it using a TWC regulator (the forerunner of Trevor Scarrat's Adverc). No more battery problems since! Changed to the Adverc when the TWC went down. Finally bought a new 2GM20 and kept the Adverc, both still running after 20+ years!


Paul Howard. S27OA Technical Officer.