Adding auxilary Power supply

[CharlesM]

Hello all

In comparing a number of boats she (my love) and I are looking at, we have found a wide range of asking prices. From what we consider to be simply excessively overpriced for a nice example, to a good price(?) for a fairly basic boat.

In order to get a sence of whether ther is a saving on the cheaper boat, I need to try determine the cost of adding (amongst other items) power supply. By this I mean solar and wind generators.

Can anyone give me an idea of the type of equipment I will need to charge the bateries. I am assuming there is already a shore power charging system...

components which will prevent over charging of batteries etc should be included.

Thanks
Charles

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[Talbot]

That question is a bit like asking how long is a piece of string. It totally depends on several factors:

how you use your boat (weekend/liveaboard/always in marina/at anchor etc.
What sort of boat (raggie or mobo).
How much do you use your engine(s).
How big is the alternator on the engine(s)
what is your battery capacity (amp/hrs of battery)
How much power do you use on an average day (energy budget),
this is an essential calculation to work out what power is required to replace that being used by nav and internal lights,instruments, heating, TV, stereo, windlass, bow thruster, fridge, freezer, autopilot etc.

From the energy budget, you will be able to work out how much additional power you need on a daily basis. You might be able to supply that by running the engine for a period each day. If you have a big budget and use the anchor, you may need a combination of solar panels and wind/water generators (I have seen a liveaboard with 2 generators and seevral solar panels) I have a 180w solar panel and will be fitting a Barden batteries and they have a good FAQ for both solar and generators. It is a good idea to have a regulator to control the amount of power going to the batteries, cause without one you can easily fry the batteries.

Types of batteries are another subject which you will need to research. My preference is for an automotive type to start the engine, and normal lead acid deep cycle batteries for the domestics, but there are other options. and you will also need to work out how large a bank of batteries you need.

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[CharlesM]

Hi Talbot.

Yes, it is perhaps a 'how long' type question. The ideal would be to liveaboard, mainly at anchor, and not to have to run the engine too much. Is the type of equipment/components required the same for generating power, with only sizes/numbers differing depending on storage capacity and consumption?

I have seen prices vary wildly for wind generators, for example, but I assume they all need the same type of components up and down the line? From a battery bank at the bottom with cables and some special charging/surge protectors ect in the middle up to brackets for the generator, and the generator itself.

I guess as regards consumption, That is a question that I have no idea how to answer. Would medium suffice hehe

later
Charles


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[Geordie]

The sums for this have been done many times in many sources. Basically it is best to assume that you need to be self sufficient - ie no shore power.

Solar panels - definitely a waste of money. for £1000 I could only put back, in one day, one-third of the energy I had used overnight running only navigation lights.

Smart regulators - One hour running the engine positively did put back in all that I had used the night before but at a cost. No matter how much I tightened my fan belt, my engine compartment surfaces were soon covered in a film of black dust. When stocking up with spares, I had been assured that my alternator brushes did not wear out. They were a good length when I set out. After 500 hours of engine running my alternator failed - because the brushes were worn down.

Shaft generators - I considered this, but decided against for three reasons: I didn,t want to slow the yacht down, I didn't want to increase wear and tear on the stern gear and gearbox, and I didn't want the rumble which comes with a free wheeling propeller.

Wind Generators - After much consideration I didn't fit one, mainly because of the noise.

I f I was to do it again I would go for a wind generator (and earplugs) and a smart regulator to be switched in only on the odd windless occassions when the wind generator couldn't generate enough.

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[William_H]

The question is more related to the type of sailing you will do and how often you will use the boat also if you will be in a berth with shore power or a swing mooring. Almost certainly you will not really know the answers until you have had the boat for some time. I would suggest you buy a boat with minimal electrics and rely on the engine for battery charging. The engine needs to be run every few weeks anyway just to avert corrosion in the cylinders. I think you will find many owners buy electronics as toys then hope to recoup the cost on resale, except electronics have poor resale value and is most likely suffering from salt air anyway. All you really need is cabin lights and nav lights a radio and a nav system. These don't require much current and any thing else you can buy when you know you really need it. For sure with boats and electronics minimum that works is far better than lots of gizmos many of which don't work (elecronics = heartaches) regards will

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[Talbot]

<<solar panels - for £1000 I could only put back, in one day, one-third of the energy I had used overnight running only navigation lights.>>

Assuming you are running 25w bulbs and are actually running 2xnav lts and stern light, overnight for 10hrs you will use 60amp/hrs. Your £1000 panel will produce in UK approx 720watt/hrs per day. (I know cause I have one) A wind generator in use while you are sailing downwind will struggle to achieve even that much.

The most effective generation while sailing is a water driven one (e.g. duogen)

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[Talbot]

sorry but medium means different things to different people, you will have to sit down and do some research for yourself. It is very easy:
start with nav lights assume tri only for 10hrs (25w bulb)
25w = 2amp/hr for 10 hrs = 20 amp/hr per day
interior lights are normally abt 10w, but check your bulbs estimate how long they wil be on for. dont forget bulbs in the instruments, the instruments themselves,

Fridges, Freezers and autopilots are the biggest users.
some items are not used every day (windlass, bow thruster etc) so work out how many times you will use them in a week, and then divide by 7.

Once you have the figures, if you need more advice, come back and we will try to help. More details in the bio would be of assistance!


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[Harveydog27]

can I ask, does shore power supply power directly to all onboard systyms whilst in dock or does it simply recharge your batteries in order for them to simply carry on supplying energy to the rest of the boat.I'm interested because I'm considering buying a us boat with us powered kit?

 

[Talbot]

This will depend entirely on how the boat is wired and what kit it has.

Shore power will normally come into the boat via a Residual Current Device and then to a breaker panel for distribution as required. Most boats have it linked to a cbattery charger which will also drive the boats 12v systems. A lot of boats will also have a mains circuit as well for high power stuff such as AC, washing machines, etc.

If you are buying this boat for use in UK you will need to research the CE status of the boat, which should resolve these problems (not essential for your own use, but essential when you want to sell within EU, plus RCD status, plus VAT.

It is possible to change over to a 240vAC, but you start by ripping out all the 110volt wiring and connections etc and basically start again!

 

[Stemar]

As liveaboard, presumably, you'll want things like TV and PC, perhaps a stereo. The first two, at least would be grateful for mains voltage, so perhaps a generator might be the answer, or at least part of it. It can also charge your 12v batteries

There are cheapish diesel generators around (petrol will break you if you use it much) and there are quite ones, but...

You pays your money and you takes your choice!

 

[Talbot]

[ QUOTE ]
you'll want things like TV and PC, perhaps a stereo. The first two, at least would be grateful for mains voltage

[/ QUOTE ]

Why - most of us manage both these very well on DC to DC converters. 95% of the equipment of this type on the home market run from DC anyway!