How much electrical grunt

[Guest]

w2ould be needed to run this?

 

http://www.go2marine.com/product/99169F ... -3342.html

[Guest]

Something like 84 amps at 13 volts!!

[too_tall 15]

BBay. I think you did not add up the maximum possible load, which the way I read it is a 550w element, two 1100w elements, a 1250w and a 1300w for the oven...

 

5.3Kw apparently.

 

at 230v thats around 23 amps

at 110v thats around 48 amps.

 

And, from battery or alternator, around 230 amps at 24V and 460 at 12 volts.

 

Genset only, as its more than I suspect most people could sustain from battery for long enough to cook dinner.

[Island Time 1,230]

Agreed TT, genset is the only practical solution. That's a s#%t load of power. ..

[Island Time 1,230]

Oh yeah, and no gimbals - launches oven.

[Grinna 2]

Looks like its only available in 120 or 240V AC ..... so that'd be genset or shorepower only.

[tuffyluffy 76]

Sure does look like genset/shore power only alright.

 

Slightly related. I bought a 12volt electric kettle from Burnsco awhile back thinking it would be a good alternative to the LPG cooker on my boat for simple coffee, cup-o-soup sort of stuff. Running on battery alone (440Ah bank), it took friggin ages to come to the boil and much, much longer than the cooker. Havent tried it with the engine running, but i doubt ill ever use it again.

[banaari 27]

This one intrigues me, because our recently-ejected friend from Opua states on his webpage he has "electric cooking".... off solar panels and purely DC battery setup. So some thoughts from a physics perspective.

 

To cook something, you:

 

(a) need to raise its temperature to a certain point, and then

( hold it there for a certain period of time

 

(a) needs energy input proportional to the thermal mass being cooked and the raise in temperature needed

( theoretically takes no further input in a perfectly insulated environment. Boiling something, in which you have to keep funding the latent heat of evaporation, screws this up rather badly. So think pressure cooker.

 

Specific heat of water is roughly 4.2 joules per gram-Kelvin. So to raise 1 litre of water from (say) 10 degrees to boiling, will take 4.2 * 1000(g) * 90(deg) = 378 kJ.

Or, since 1kW = 1 kJ / second, about 6 minutes with a 1 kilowatt element to boil one litre.

 

Or, @12 volts... 83 amps for 6 minutes. Which sounds a lot but isn't extreme in the context of your typical alternative-power setup.

Now, if you weren't using your power for propulsion; had a LOT of solar panels, didn't care didly for the weight penalty of your battery bank, and had built yourself an uber-insulated oven....

 

Discuss.

[Guest]

I love where this thread has headed.

 

I was thinking how I'd like to go electric drive, but it wouldn't happen unless my perfectly good diesel engine shat itself and needed to be replaced. Then I thought that were that the case the only fuel I'd have to "import" would be propane. So I was wondering if it would be possble to do away with that.

Not looking too good.

[wheels 543]

That'd have to be one hell of an electric system to move your beast around Squid. So if you had enough spark for moving the boat around, then you would have plenty for the cooking side of things.

[Guest]

Why not go for a hybrid diesel electric David? Seems easy to set up and it would give you plenty of grunt for an oven or air conditioning. You could use the electric most of the time and when you need the charge, speed or distance, start the diesel. You would then be able to motor sail quietly using little current which I think would be one of the biggest advantages of electric.

[Guest]

I have saved a link to a diesel / electric system.

 

But to me the joy would be to disconnect from the shore as much as possible, i.e. zero diesel. Each to his own.

 

As I say I'm not wealthy enough to toss a perfectly good engine just because, but I can't stop myself mindsurfing.

 

Then there's always peak oil.

[Jon 360]

I had a solution for you untill you said disconnect from the shore.

 

Collect driftwood from shore burn it in a boiler use steam for propulsion and heat for cooking ?

 

Be great in the tropics

[Guest]

I met a chap who built a boat for charter in the Pacific North West, exactly as you describe. First day all the passengers went ashore with chainsaws to collect wood, then that covered the trip for heating, cooking and propulsion.

[wheels 543]

I have saved a link to a diesel / electric system.

Would the link be "Dreamliner Power storage system"

[Guest]

this one

 

http://www.hybrid-marine.co.uk/5.html

[rigger 47]

If you are serious about generating spark to run an engine talk to Mike at Websters electrical.

 

I spoke to him about a power system for a very specific function - came back with an interesting system that was a UPS with generator - match to the max draw so that the generator would be running at load to charge the batts + run the system and would then shut down when batts topped up.

Good points - engine always running under load, less engine hours and if power draw is less than max the batts will run everything for that much longer, from memory we had required a 4hour capacity in the system at max draw before engine cutting in to recharge the batts.

[Guest]

It needs not be too expensive I think. A simple motor coupled to the prop shaft by belt, some bracketing, extra batteries and controls. Then you have much more electric power aboard for house loads. In this system the electric motor does not need to drive at hull speed , a few knots is all that is needed as the diesel will give range and hull speed when needed. Thats a good point Rigger has raised where the motor is under load which is apparently good for a diesel. Your speed under sail would probably be enough to regenerate some useful power.

So with enough solar panels you could motor under their power alone which would be great in the tropics. The panels are cheap now, I see on trademe flexible 100 watt panels for around $300. these could be attached to 6mm occume ply and hinged at the top of the lifelines with some method of holding them horizontal when needed. These would get good power early in the morning and late evening due to reflection off the water and could also be pointed at the sun at various times during the day. Ten of these will give you 15 amps at 48 volts which would keep you motoring. These would take up 6250 mm along each side by about 550 mm. I'm just guessing at this but maybe good for 3 knots.

[wheels 543]

I have said it sooo many times. It is expensive and every time you convert energy from one form to another, you have losses. At present, no matter what storage devices you look at, they come at a cost. It costs you room, weight in some cases and certainly in financial cost. You still have to have a Genset, which means an engine and an expensive thing at that, so you may as well just have an engine.

 

Squid, I was "tongue in check" refering to the issue the Dreamliners are having with the batteries catching fire.

It may well be that the Dreamliner issue is the very thing that creates that change in storage technology the world needs to see. Shoving a potential explosive Battery into a metal box is not the kind of advance the world needs, but I am sure someone will come up with something.

[Guest]

Hadn't looked at dereamliner link yet, will do.

 

Wheels I agree with all you say except for one thing. You MUST have a generator. That's simply a matter of how big a compromise you are prepared to make. I'm prepared to make a pretty big one if I can get rid of the ICE.

Happy with say 24 hrs @5kn. Happy if I can recharge quite slowly, say 7;1 under sail, at anchor as long as there is a surplus no matter how small.

I know a lot of people wouldn't find that acceptable, but I woulld.