How many alternators?

[UseleSS Enterprise]

I just went to see a boat for sale which has three alternators driven by the engine. One charges a starter battery one charges a domestic bank of batteries and the third seemed to power an internal AC generator but I didn't understand that. Is this unusual or could the same power be provided more economically. Oh yes, and the three were driven by two belts (one drove one alternator and the other drove two of them) one of which was protesting with a screech when the engine was run. Apparently it just needed tightening but there didn't seem to be any play in the belts. I won't be going back.

[Robbo]

Sounds like the third is a Travel Power, a 240v generator ran from the engine.

 

It's not unusual and it's recommend to use multiple alternators for multiple battery banks, but high amp alternators do put more strain on the belts so it's better to have these upgraded. The screech is most likely a worn belt.

Edited August 11, 2016 by Robbo

[WotEver]

What you describe is quite common. A small alternator (maybe 50 or 70A) will charge the starter battery, which really doesn't require much in the way of charging. A much bigger alternator (maybe 150A) will charge the leisure bank which requires much more charging. The two alternators can be paralleled in order to get the initial charge into the leisure bank a little faster. The third alternator is what is known as a Travelpower and is a great way of generating high power 240V straight from the engine - think running the washing machine whilst cruising.

 

The screeching belt may well have been because the battery bank was very low and the demand on the large alternator was at maximum. It could be that the batteries are shot, or it could be that the belt is loose and/or worn. It could also be a badly configured belt arrangement.

 

Tony

As it stands, nothing you describe would put me off the boat - quite the opposite in fact.

[Guest]

I just went to see a boat for sale which has three alternators driven by the engine. One charges a starter battery one charges a domestic bank of batteries and the third seemed to power an internal AC generator but I didn't understand that. Is this unusual or could the same power be provided more economically. Oh yes, and the three were driven by two belts (one drove one alternator and the other drove two of them) one of which was protesting with a screech when the engine was run. Apparently it just needed tightening but there didn't seem to be any play in the belts. I won't be going back.

Fairly standard setup in these power hungry days. At one time the "small" alternator that charges the start battery would have been massive, and to die for, but things move on.

At the danger of becoming a Monty Python sketch, my first NB had a single 45A alternator, and after being used to outboard motors, this was pure luxury

[WotEver]

At the danger of becoming a Monty Python sketch, my first NB had a single 45A alternator, and after being used to outboard motors, this was pure luxury

 

Luxury? You don't know the meaning of the word...

[Guest]

 

Luxury? You don't know the meaning of the word...

[Stedman II]

Our share boat used to have this arrangement on a Beta 43 - until one day all the pulleys fell off the drive shaft whilst ascending Meaford locks!

[nicknorman]

Three alternators is a good thing in principle. As mentioned, one for the engine battery, one for the domestic battery and one high voltage one for a Travelpower (source of mains power). However I would want a closer look if there were only 2 belts since to run a large alternator and a Travelpower off 1 belt will be a huge load and with not much belt wrap, bound to be prone to slipping. I think some Barrus engines have this configuration?

 

Ours has 3 alternators but 3 belts which seems a much better system (Beta 43) although as mentioned there have been some problems with pulleys coming adrift. Not on ours fortunately. Yet!

Edited August 11, 2016 by nicknorman

[UseleSS Enterprise]

Great replies. Thankyou. I have learnt a lot.

In this particular case I think from what you say, that it may be down to the batteries being poor and there were other electrical problems through the boat.

[WotEver]

In this particular case I think from what you say, that it may be down to the batteries being poor and there were other electrical problems through the boat.

 

What other problems? New batteries are a good negotiating point for getting the price down, so that's no worry. What were the other problems?

 

Tony

[Eeyore]

I just went to see a boat for sale which has three alternators driven by the engine. One charges a starter battery one charges a domestic bank of batteries and the third seemed to power an internal AC generator but I didn't understand that. Is this unusual or could the same power be provided more economically. Oh yes, and the three were driven by two belts (one drove one alternator and the other drove two of them) one of which was protesting with a screech when the engine was run. Apparently it just needed tightening but there didn't seem to be any play in the belts. I won't be going back.

Nicknorman is probably right about it being a Barrus Shire engine. The two 12 volt alternators share one "V" belt and the Travel Power alternator is driven by a polyvee (flat) belt.

Check the pulleys on the 12 volt alternators for burn marks caused by slipping belts, they are are silver/bronze in colour when new, and a dark blue when overheated by a slipping belt. Experience with this "V" belt arrangement varies a lot, for some its an annual belt change "just in case" and for others its an endless battle. There was a conversion for engines fitted with twin 12 volt alternators to a twin belt system, but I don't think this was an option with the Travel Power alternator fitted.

Check for modifications to the 12 volt domestic alternator installation and its wiring, the original was an 80 amp Hitachi which proved to be somewhat unreliable. Lots of "home-brewed" remedies out there.

Steve (Eeyore)

Edited August 11, 2016 by Eeyore

[Phil.]

(Beta 43) although as mentioned there have been some problems with pulleys coming adrift. Not on ours fortunately. Yet!

There is a retro fit part available to prevent this. Costs about 50 quid and took me 15 mins to fit.

[nicknorman]

There is a retro fit part available to prevent this. Costs about 50 quid and took me 15 mins to fit.

Yes I keep meaning to look into it. Note to self: GET ON WITH IT!

[WotEver]

There was a conversion for engines fitted with twin 12 volt alternators to a twin belt system, but I don't think this was an option with the Travel Power alternator fitted.

 

Nick stated that his setup has three belts.

[Sea Dog]

There is a retro fit part available to prevent this. Costs about 50 quid and took me 15 mins to fit.

Is there? I don't have the travelpower, but I understand the failures haven't necessarily been just those engines which do. Please tell me more!

[Phil.]

Is there? I don't have the travelpower, but I understand the failures haven't necessarily been just those engines which do. Please tell me more!

The best way I can describe it is as a circular disc of plate metal which has smaller grooved hole section protruding from it. This is slide onto the end of the exposed shaft until the circular plate section meets the face of the pulley and is bolted to the existing pulley using slightly longer bolts.

[OldGoat]

Stedman II, on 11 Aug 2016 - 1:15 PM, said:

Our share boat used to have this arrangement on a Beta 43 - until one day all the pulleys fell off the drive shaft whilst ascending Meaford locks!

 

Snap! - but not at Meaford...

UseleSS Enterprise, on 11 Aug 2016 - 3:14 PM, said:

Great replies. Thankyou. I have learnt a lot.

In this particular case I think from what you say, that it may be down to the batteries being poor and there were other electrical problems through the boat.

 

If you have any plain v belts - then fit the 'toothed' or 'cogged' variety. Last a lot longer and handle small pulleys better.

Wit a high powered alternator setup - the belt invariably squeal if you run at tickover - just increase the speed a tad and it'll go away.

 

Phil., on 11 Aug 2016 - 5:19 PM, said:

There is a retro fit part available to prevent this. Costs about 50 quid and took me 15 mins to fit.

The kit only works on engines where Beta didn't chop off the extension shaft (that was only in very early engines).

The plate fits over the splines and takes the load rather than the rather-small-key that was only designed for the domestics. As Phil says it's easy peasy (if you can get at things.....)

[Arthur Brown]

I'm sure there will be an electricity free boat somewhere on the system, but most current boaters use some or LOTS of electricity. According to your needs I'd suggest that three well chosen, well fitted alternators would give you all that you want in terms of power and voltage, also you'd always have the possibility to survive a first alternator failure without issues.

 

I'd consider it a good point.

[magnetman]

Seems quite a lot of power to take off the crankshaft at the front of the engine if all the alternators were at full load

 

I guess this will have been taken into account by the designer .

[Sea Dog]

The best way I can describe it is as a circular disc of plate metal which has smaller grooved hole section protruding from it. This is slide onto the end of the exposed shaft until the circular plate section meets the face of the pulley and is bolted to the existing pulley using slightly longer bolts.

 

[quote name="OldGoat" post="1864680" timestamp="1470935862"

 

 

The kit only works on engines where Beta didn't chop off the extension shaft (that was only in very early engines).

The plate fits over the splines and takes the load rather than the rather-small-key that was only designed for the domestics. As Phil says it's easy peasy (if you can get at things.....)

 

Thanks for the info fellas, appreciated.

 

Is the modification Beta's own and do they supply it?

 

OG, do you mean it was only the early engines they chopped the shaft off, or t'other way round?

 

Mine's a 2008 with 2 alternators but no travel power - does it need the modification and will it fit?

[Phil.]

Thanks for the info fellas, appreciated.

Is the modification Beta's own and do they supply it?

OG, do you mean it was only the early engines they chopped the shaft off, or t'other way round?

Mine's a 2008 with 2 alternators but no travel power - does it need the modification and will it fit?

It is designed by beta and seeing their engines at crick it appears it is a standard fit to new engines. If you phone beta and give them your engine woc number they will know the build from their records and advise accordingly.

[Sea Dog]

It is designed by beta and seeing their engines at crick it appears it is a standard fit to new engines. If you phone beta and give them your engine woc number they will know the build from their records and advise accordingly.

Thanks Phil, advice appreciated.

[cuthound]

When I had DQ surveyed, the surveyor told me that early Beta's used a keyway to drive the alternator pulleys, which often failed, but later ones from around 2006 had splines in an elongated output shaft, which allows the pulleys to be driven from several points, not one as with a keyway. He said he had not seen any pulley failures with the splined shaft.

 

I would check to see which type of pulley drive shaft this boat has.