Wildfuzz

Does Anyone Have Any Knowledge

18 posts in this topic

What are the pros and cons of using one of these on a boat with no hot water system, is it viable, practical and safe?

 

S.

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Hi Stuart, 

I have no experience of these, if you have the battery power available and the correct size stranded cable to supply this immersion heater, then it should be fine.

It will draw 25 amps at 12 volt so a minimum of 2.5 mm2 cable is required for a short run, longer I would go for 4mm and it will need a 30 amp breaker to control it.

Regards

Alan

Vaughan likes this

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I think the key word is "immersion" as you might get problems with electrolytic action.

25 amps is a lot of power at 12 volts and running this for one hour would effectively use half the usable power of a 110 A/H battery.

This sounds like the sort of thing you would only turn on when the engine is running. You would need an awful lot of solar panels, to power this on their own!

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An Origo alcohol hob ( if you do not have gas aboard ) would warm you up some water a lot quicker. Alcohol/Meths is a tried and tested source of heat on boats for years and one of the safest.

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I would guess at 300w dc in a hot water tank of boat size its going to take a very very very long time to heat up the water and in dc terms use an enormous amount of energy in doing so.  

Depending on tank size it may not even be enough to make the water luke warm before it flattens the batteries anyway.

It says it can be used to stop livestock water freezing, unless they are having a brew I dont think the animals drink hot water!! 

 

Vaughan likes this

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I have a 12v kettle don't know the wattage but it takes 25 minutes to boil a mug of water!

Used it twice now lying at the back of my work room collecting dust.

paul

Vaughan likes this

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https://www.amazon.co.uk/Highlander-Solar-Shower-Black-Litres/dp/B0010A377C

Hope the link works.  We had something like this a few years ago when we owned a 21 foot cruiser on the Kennet and Avon canal.  Worked fairly well not overly hot.  

In a previous caravan we had a 12v kettle for warm water, but as previously mentioned it did take rather a long time to work!

SueH 

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If you have an inboard engine then it is best to fit a proper calorifier heated from the engines cooling system. If you have an outboard naturally you can't heat water from it and this is where one of these would seem logical. Trouble is an outboard has a very low output charging system and would not give enough current to operate one. If you had 3 x 100 watts solar panels then it would be different but 3 panels take up a lot of space. I think these gadgets are more designed as a dummy load for wind turbines to prevent alternator damage when turning fast but on a light load. We used to have a similar thing at sea for putting a 300 amp dummy load on the generator if it was running at light load, particularly if the engine was a two stroke diesel.

 

cheers

Trev

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Remember 3x100 W solar panels is max theoretical installed output not average and bears little resemblace to what you will get on a cloudy day in Norfolk so lukewarm would perhaps be a stretch. Hot sunny day is different and then the're great. (output drops off when they get hot) Cost vs benefit is a real bummer. We are thinking of getting some for the convenience of topping up the batteries when the fidge is going nuts making ice for the cocktails, but where to put them on a woodie that doesn't ruin the aesthetics and originality is the problem. We may just stick with a bag of ice cubes from Roys. As my son would say "developed world problems"...

 

The latest techy flexible roll out ones are great but I dont want to sell the children to buy the panels.

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Gonna go for a couple of these and some warmed water from the kettle, much nicer / cheaper / easier..... :angel::221_see_no_evil: No peeking as you go by if the canopy is up!!!!!!

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25 minutes ago, Wildfuzz said:

Gonna go for a couple of these and some warmed water from the kettle, much nicer / cheaper / easier..... :angel::221_see_no_evil: No peeking as you go by if the canopy is up!!!!!!

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I have to say I would go for a couple of those only, for the life of me I can't work out where the plastic bottle and the straw come into the equation. However, I'm under instruction from Ellie that RT's toilet and shower MUST be luxurious. After a tour around Nipper with Hele, Ellie...now can anyone else see the problems that ensure when Doug and I moor boats adjacent...has decided that RT's loo not only needs replacing but needs relocating within the cabin space as does the shower which needs a tray not painted boards with holes in.

I think we are going from bucket to Versailles in terms of grandeur while I'm doing impersonations of Foggy Dewhurst with his purse!

riyadhcrew, Wildfuzz and Jonzo like this

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Tim the straw is part of the cap, it allows air into the closed end of the bottle preventing a vacuum. the plastic bottle you provide yourself.

Timbo likes this

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1 hour ago, grendel said:

Tim the straw is part of the cap, it allows air into the closed end of the bottle preventing a vacuum. the plastic bottle you provide yourself.

Now I'm thoroughly confused Grendel. So I keep my cap on with a straw in it and I provide the plastic bottle and a vacuum. What do the two blonde's bring? :shocked

Maxwellian and Jonzo like this

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Posted (edited)

2Lt for a shower..... Don't you just love optimism. I can manage a standup wash but be lucky to get an arm done with 2Lt and get the soap off.

we have used the gellert style solar heaters in the past and still have one but forget the shower and use it for free hot washing up water. The plastic hose they come with is rubbish. Change it for one that won't kink. If left on the coach roof on a nice sunny day can produce water too hot to put your hand in so beware.

Colin

Edited by Islander
Predictive text again

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 What do the two blonde's bring? :shocked

 

one very memorable night...............................................................:hardhat:

lakesailor likes this

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We are all assuming that the 300w heater is being asked to heat the tank from cold, but what if you have a standard inboard engine and calorifier set up, a large domestic bank of batteries but either dont have shore power or access to it.   A few hours chuggin gives a tank of hot water, well insulated this lasts well but does cool, so does this immersion just kick in at times keeping the tank above 50degs and the benefit of a nice warm shower in the morning without running the engine?

Someone buy one at let us know how you get on!

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