240volts on board

[rigpigpaul]

I have been looking at ways of producing 240volts while at anchor. I only want it a occasionally, power tools, microwave and only for short periods. I have seen the honda 2000i for 1000 pounds or an alternative could be a 3.5 Kw alternator(ac generator) from machine mart for 211 pounds or a 6 Kw alternator for 400 pounds. This could be driven from a 2:1 ratio pulley off the engine and the belt could be left off when not in use. I know I would have to keep an eye on the engine revs. and output voltage and I know it is a very crude system.But it seems a waste of money to have a nice piece of kit sat in the locker when I can buy an alternator with twice the output (plus two pulleys and drive belt) for half the price.
Does it sound like a daft idea?
regards Paul.


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[Talbot]

I know somebody who has gone down this route + invertor and large battery bank to make his boat fully lectric. Their reason was that where they are going supplies of gas are difficult. Personnally the drive belt wear would worry me, but not half as much as the thought of 230v at sea. I have a small generator for power tools and emergency use. They can be purchased for less then £100,

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[ashley]

would it be right to think that 240 volts is more dangerous than 12volts?
your 240 source would be protected by an RCD. It would trip out if the system got wet or you had a short and would be cut off in milliseconds.
12volts batteries are capable of almost 1000 amps and with some parts of your system having only a slow blow fuse in the circuit, and usually none across most starters, you surely would be at greater risks with this sort of current flowing in wet eletrics.

current kils, not voltage, is that not right?

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by ashley on 15/08/2004 04:44 (server time).</FONT></P>

 

[Xpat]

Where can I get a small generator for less than 100 pounds? Do you mean second hand. I have been considering the honda but it's 10 times that price. Still a lot cheaper than a deisel generator though.

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[Talbot]

be interested to see your 12v battery that is capable of 1000 amps! Deep cycle batteries have difficulty producing large currents, whereas engine start batteries are designed for it. despite this, my engine start is only capable of 400cca (cold cranking amps) Most 12v cable is totally unable to carry much more than abt 20 amps without damage to the cable. High ampage is provided to the switch panel (probably around 50 amps) and the biggest ampage circuits will be to the windlass or bow thruster circuits (abt 100-200 amps). If you think it is safe with your RCD, have a word with the gentleman who was electrocuted during a storm onboard his boat (covered in PBO) - myself, I would rather run with 12v - you can actually run 12v motor underwater for some time, but I wouldnt try that with a 240 unless you wish to feature in the darwin awards. /forums/images/icons/smile.gif

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[Talbot]

Frequently available on <A target="_blank" HREF=http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=46412&item=4318853297&rd=1>ebay</A>

Also from D-I-Y stores in UK at abt same price. The honda is a lot quieter, the honda 1000 is cheaper and will do most jobs that you require, it slighter and cheaper than the 2000

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[redhot]

Take a look at Makro.
They are doing a 850W (I think) generator for £59.99 + VAT.

Thanks
Mike

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[ChrisE]

Notwithstanding Talbot's dire warnings about the use of 240v at sea, if your needs are light, say less than 700w then an inverter would do the trick at less cost than the generators. We had one fitted yonks ago and wouldn't be without it. Mrs Enstone even vacuum cleans the boat now as we sail along!

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[Tomsk]

Places like B & Q are curently selling generators at around £100 for approx 1kva I think...

<hr width=100% size=1>Tomsk -

Can I leave the planet please.. this one is broken!

 

[MainlySteam]

I am with Chris on this one.

Wooed much by the small petrol generators I have wondered about this alot. However, after considering their generally floating neutrals and the possible consequences of that, and the CO and fire risk (now with the loss of the beautiful new Scottish yacht Spark through such a fire) I would never consider having one on my boat under any circumstances except shoreside to power a single tool during repairs and shorepower not being available.

We have a 1 kW invertor and that does most all we want at the cost of running the main engine for battery charging (putting aside the capital and maintenance costs, we are probably a little small for a permanently installed generator).

John

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[DogStar]

Don't inverters trash your batteries sooner? If not I'd love to fit one, just to not have to run the genny every time I want to use one of my few 240v gizmos.

My solution to having 240v readily to hand was getting a 5kva diesel genny from ebay for £650. It will sit nicely in my engine room, properly mounted & vented, and can share the fuel supply from the main tank, which means it can run constantly if needed.

Does anyone know if the old 2v deep cycle cells can be easily reconditioned? I have a set, but the top of one is damaged. Is it worth it?

<hr width=100% size=1>I'd rather have a bottle in front of me than a frontal lobotomy!

 

[MainlySteam]

Well, if you want 5 kva then an installed generator is the obvious way to go if one has room for it.

For the case of powering smaller "gizmos" then an invertor will not trash your batteries as long as you have enough amp hours of battery capacity installed so that you do not discharge them below 50% (which they should preferably never be discharged below invertor or not) and have enough plate area to supply the current required without the voltage sagging below that required by the invertor for its operation.

John

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[pragmatist]

Where on earth do you store a vacuum cleaner on a Rival ? I've got one of those naff rechargeable jobs and even that hasn't got a permanent home (maybe we should tow a storage yacht behind - plainly you and Mrs Enstone don't stuff your lockers with all the rubbish we do !)

<hr width=100% size=1>a pragmatist is an optimist with a boat in the UK

 

[ChrisE]

Ah, we have one of those compact jobbies about 15" high with hose and gadget things. Also, I take exception to being accused of not stuffing our lockers with junk. I've got six cases of wine somewhere on the boat, if only I knew where they were.

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