Small and light battery charging

qsiv

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I need to find the smallest, lightest aircooled engine which can drive an alternator for onboard charging.

In this search weight (or lack of it is everything) - the objective is to top up 24v batteries on a new race boat. The engine doesnt have to drive the boat, and I would rather not have a through hull fitting, for performance reasons. The exhaust must exit over board, via a long run to the stern. I cant use a nice little portable Honda genny, as portable genny's cant be used below, and all genny's have to be permanently installed. IAE, I would rather not have petrol below decks.

So far the smallest I have found is a Farymann 5 - which weighs about 37Kg, ex alternator. Can anyone do any better?

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pvb

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Robin Diesel...

Have you seen the little Robin diesels which are used on small plant hire machines such as water pumps and concrete compactors? They're air-cooled, recoil start, really compact. The smallest one they do is about 5hp, and my guess is that it would weigh in at less than the Farymann.

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qsiv

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Re: Robin Diesel...

Thanks - I've asked them for a weight - they dont give it on their web site. It **looks** very similar to the Farymann

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tgalea

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Just one comment. I'm undoubtly not into racing so please forgive my ignorance on the subject but i've had farymann for a long time now... and it's a great engine.

Runs like a dream and after 5 years of service still acts as if it was new.

Hope that helps !

Regards
Tyrone.


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qsiv

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Thanks!

The new boat will have a high electric demand - but wont have an inboard engine. As the outboard cant be run while racing, I need an alternate charging mechanism. As I'm concentrating on weight reduction elsewhere (carbon rig, PBO rigging, carbon sails), I'm not keen to add any more weight than I have to in order to recharge the batteries.

Is your Farymann an aircooled one? If so is it horrifically noisy, or just plain noisy!?

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Jools_of_Top_Cat

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on one of our family boats we had an 8hp lambordini recoil start diesel, used about 1 gal per 7hours running. Was a bitch to start, a couple of times it took the rope back around the flywheel.

From what you say I see a problem with cooling down below as even in the open cockpit with a well ventilated engine box it would get quite hot. You might have to fit some pretty hefty fans to keep air running past the fins.

Have you considered a couple a wind gens on the stern, would give plenty of power without noise and prolly much less wieght. Or some hefty solar panels?

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qsiv

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Thanks. I dont think solar will be up to the mark in N Europe. Win gens are really surprisingly heavy - and put the weight right at the end of the boat - just where a race boat doesnt want it.

I take your point about cooling - I doubt that the engine would need to run for very long at a time, but I should take acount of it. Mind you in an engine box in a lunch there isnt great airflow - and ont forget the combustion process itself sucks in a fair amount of air.

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byron

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<font color=blue>Jeeze! I seem always be mentioning this firm but I assure you I have absolutely nothing to do with them. Speak to Marlec Marine in Ramsgate, they build gennies and are real experts, they always have dozens of new & recon. engines in stock too. The dude there you need speak to is Mike Roberts.

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qsiv

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Thanks Byron. I hadnt seen you mention them before but I'll get in contac with them now. I'm only after a DC output but otherwise what I'm after would be recognisable as a really small genny!

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qsiv

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That looks just perfect - as the boat is being built in California, it's even better.

If I discard the frame we will save even more weight - which will make up for the additional weight of mountings and bearers (not that they will need to be too substantial for such a tiny device.

Brilliant find thanks a lot!

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tgalea

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mine is water-cooled but farymann make them air-cooled too. As you said,the farymann is a single cylinder engine and yes it is noisy. To be exact it sounds like a diesel water pump or a diesel agricultural machine.... but as i said it's a great engine, very simple wiring, self-priming (no-bleeding necessary) etc..

hope i've helped.
regards
Tyrone


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