3GM30 High Power Alternator

[jfkal]

Anyone with experience in using a high power alternator on the Yanmar 3GM30 engine. Max Power for a replacement of the original alternator and how to fit an additional alternator and its max rating. All help and advise appreciated.

 

[salamicollie]

Trying talking too the guys at BM Adverc - they are usually very helpful in these matters

 

[jimboaw]

I had a 3hm35 with a twin alternator setup The second 120 amp alt was mounted with a steel plate affixed to the front of the engine. Problems were constant!!
First of all the mount could not be made stiff enough to maintain belt (twin) allignment when the alt kicked in and out . Second the thing drained so much power from the engine. Perhaps you have power to spare but I only had 35hp in a heavy 40 footer. I would just replace the factory (55amp?) with a larger one IMO. Good luck

 

[sjohn_gibson]

I can not advise on your specific case but you may wish to note my experiences. I fitted a 130 amp alternator to my Mercedes 636 2 years ago. I am still struggling to find a satisfactory solution to driving the alternator.

The orginal 'V' belt (B) layout is one crank pulley drives engine water pump and alternator; second crank pulley drives salt water pump.

Initally, the belt slipped so I increased the alternator pulley diameter (sacrificing alternator output) but still had some belt slip - belt dust every where. Fitted idler pulley to increase belt contact on alternator pulley. Worked perfectly for 7 hours - the belt fatigued because the reverse bending over the idler pulley was to severe. Tried notched 'V' belts - lasted longer but still suffered from fatigue cracking.

I am now considering a major re-engineering exercise to lengthen the engine water pump shaft so that the pumps are driven by one pulley and the alternator via the other pulley.

I am open to advice if anyone has been down this road already.

I just love hanging upside down in the engine bay with its limited clearance.

 

[pvb]

Single V-belt drive?

If you can only use a single V-belt to drive the alternator, I'd suggest you don't go above a 90amp unit. Anything much bigger will suffer from constant belt-slip problems and will fill the engine compartment with black rubber dust. Additionally, you need to keep to a small-case alternator format to minimise mounting difficulties.

I'd also recommend that you talk to the guys at Adverc; they offer a good range of higher power alternators. I bought a 90amp Leece Neville unit from them, and it works brilliantly (hooked up through an Adverc regulator of course). Prior to that, I had a 130amp large-case alternator which suffered from belt slip and repeatedly broke its bracket.

 

[42_South]

We upgraded our 18hp to the 27hp Yanmar when we bought the boat 18 months ago, as it was somewhat underpowered.

The old engine was already fitted with the standard Yanmar alternator, plus an additional one (115amp) that serviced the house bank. In the event of failure, either alternator will charge either battery bank if both banks are selected.

The new engine readily accepted the same installation and I have had no problems whatsoever, not even any wear of the belts.

It is important that if fitting a second alternator that you have seperate belts, as this adds to the redundancy and this will require an additional pulley on the crankshaft. Also the type of belt and amount of surface contact is important as discussed in previous posts.

 

[jfkal]

Great News. Do you have pictures and/or drawings you could send me?
joerg.kalisch@dexteritas.com. What is the make and model of your 115 Amp alternator?