0.5l cordless kettle 240v

[peterboat]

1 hour ago, Alan de Enfield said:

 

Just because it is 760w, why should that make it 'energy saving' ?

 

It will just use exactly the same energy (maybe slightly more) and will take 3 times as long as a 2kw kettle. 

SWMBO struggles with this concept.

Because my inverter on the camper can only do 1000 watts! plus when on some sites plugging in a normal kettle results in lecce cut off!

[Alan de Enfield]

28 minutes ago, peterboat said:

Because my inverter on the camper can only do 1000 watts! plus when on some sites plugging in a normal kettle results in lecce cut off!

 

But, as has been explained, that is not 'energy saving' is it ?

You just use (say) 1/3rd of the power for 3 times as long. 

 

It takes a certain amout of energy to boil 1 litre of water irrespective of doing it in 1 minute of 10 minutes.

 

I believe these are the accepted figures :

 

To boil 1 litre of water from 20C to 100C, requires 0.183 kWh

[peterboat]

49 minutes ago, Alan de Enfield said:

 

But, as has been explained, that is not 'energy saving' is it ?

You just use (say) 1/3rd of the power for 3 times as long. 

 

It takes a certain amout of energy to boil 1 litre of water irrespective of doing it in 1 minute of 10 minutes.

 

I believe these are the accepted figures :

 

To boil 1 litre of water from 20C to 100C, requires 0.183 kWh

 

Alan read what I have put! I have a 1000watt inverter the kettle is 760 watts it will work,  also on some sites a 2kw kettle blows the electrics 

[Alan de Enfield]

32 minutes ago, peterboat said:

Alan read what I have put! I have a 1000watt inverter the kettle is 760 watts it will work,  also on some sites a 2kw kettle blows the electrics 

 

Read what I said that you replied to :

 

Why is it energy saving because it is only 760 watts ?

 

You had previously posted you had a 1000w inverter so it is obvious why you would buy it, but surely with your knowlegde of electrics you accept that it is not 'energy saving' as advertised, it is simply of a suitable 'wattage' to be powered by your inverter.

 

We have a 900w 'George Forman' grill, a 900w electric toaster, an 800w electric kettle, and a 1500w (750w output) microwave for the simple reason we have an 1800w inverter.

No of these save energy compared to my 'big' appliances at home, do they?

[cheesegas]

It's also worth noting that if you have a 2kw kettle which you switch on while running the engine, unless you have a massive alternator it will not be able to keep up with the 170 or so amps required. The batteries will make up the difference, and drawing sustained high currents from lead-acids isn't very efficient. They'll need to charge - slowly - after each kettle is boiled.

 

However, a 750w kettle will need around 70 amps, most of which the alternator will be able to supply.

[TheBiscuits]

1 minute ago, cheesegas said:

It's also worth noting that if you have a 2kw kettle which you switch on while running the engine, unless you have a massive alternator it will not be able to keep up with the 170 or so amps required. The batteries will make up the difference, and drawing sustained high currents from lead-acids isn't very efficient. They'll need to charge - slowly - after each kettle is boiled.

 

However, a 750w kettle will need around 70 amps, most of which the alternator will be able to supply.

 

Conversely, I'm thinking of adding an electric kettle to the galley for summer use, as I have plenty solar and Calor is now forty quid a bottle.

 

Might as well have a sunshine brew - but I'll not be getting a one cup kettle.

[ditchcrawler]

8 hours ago, Tony1 said:

 

If you find a cordless model that boils in 3-4 mins do let us know.

I recently bought a 1000 watt 0.5 litre corded model, and its not ideal having to unplug it and then have the very short lead dragging the plug around the worktop, through occasional patches of water, etc. 

My solution was to leave the electric kettle in situ, and to use my gas kettle to fill it.

I was thinking about making the cable two feet longer so that it will reach the sink, but I'm very hesitant as there is usually a good reason for the sizing of cables.

 

I'm sure you'll have considered this, but just in case- if your batteries have run down below 50% overnight the voltage might be around say 13v (depending on whether you have much stuff running in the mornings).

What happens with me is that the sudden pull of 80 amps for the kettle drags down the battery voltage to 12.8 or 12.9v. 

If your SoC is lower still, you might risk tripping your low voltage disconnect.

 

I got round this potential issue by using the BMV712 to set a 5 minute delay on the low voltage disconnect (the kettle boils in 3 mins), but not sure if the battery protect allows a delay. 

 

 

I have seen someone holding a tap and plugged in kettle with an earth fault, I think I found it more amusing than the lady holding the tap and kettle 

6 hours ago, Alan de Enfield said:

 

Do people really do that ?

 

They do

 

[Tony1]

2 hours ago, TheBiscuits said:

 

Conversely, I'm thinking of adding an electric kettle to the galley for summer use, as I have plenty solar and Calor is now forty quid a bottle.

 

Might as well have a sunshine brew - but I'll not be getting a one cup kettle.

 

As well as having free energy available anyway from the solar, there is another issue involved- which I discovered on the hot days this summer. 

When the boat interior is already at 26-29 degrees, the last thing you need is to fire up a gas ring for 6 or 7 minutes to make a brew. It seems to add a couple of degrees to the kitchen and saloon temperature, making things even more uncomfortable inside. 

On the other hand, using the gas kettle is a great way of helping things to warm up a bit faster when you get up on a chilly late Autumn morning, and its one of those days when its going to warm up and its not worth lighting the stove.

 

But the stove's now been lit, and it may stay on all the time for a few days or even weeks, so the saloon is warm enough in the mornings anyway, and so I've all but stopped using the whistling kettle.  

 

I reckon that boiling water for drinks probably accounted for about a third of my total gas use, so the gas bottles will now last a few weeks longer than before.

For the last year I've been fairly consistent in using a gas bottle every 2 months or so, so its not a huge saving, but in the heat of the summer it'll be great not having to use the gas kettle. 

 

[TheBiscuits]

Just now, Tony1 said:

the stove's now been lit, ... and so I've all but stopped using the whistling kettle.  

 

Odd choice Tony.  Put it on the stove!

 

If the stove isn't quite hot enough to fully boil it it should only take seconds on the hob to get the few extra degrees.

[Tony1]

14 minutes ago, TheBiscuits said:

 

Odd choice Tony.  Put it on the stove!

 

If the stove isn't quite hot enough to fully boil it it should only take seconds on the hob to get the few extra degrees.

 

I tried cooking and boiling on the stove last winter and it seemed to take quite a while- which is ok for cooking, but a pain if you're waiting for the kettle.

My electric kettle is done in 3 mins, which first thing in the morning is very much appreciated. 

 

The stove at that time of day is not at its hottest, so it would take a good while to boil. Later on it would be no problem.

One of the things is that the gas kettle has a vertical lip around the bottom edge which means the lower flat surface is not in direct contact with the stove, and it really slows down the boiling process. 

 

But you do have a point- now that the solar 'party' is largely over for this year, and I'm going to have to pay for the electricity used by the kettle, I might as well use the stove to heat up the water in a pan, once its properly fired up, and then finish the boil on the hob. 

It seems a faff though, to be honest- not sure if I'll be arsed to do that most of the time. 

 

 

Edited October 21, 2021 by Tony1

[TheBiscuits]

6 minutes ago, Tony1 said:

One of the things is that the gas kettle has a vertical lip around the bottom edge which means the lower flat surface is not in direct contact with the stove, and it really slows down the boiling process. 

 

That's no good.  Get a decent kettle that doesn't have this design flaw.  Or a round bit of metal that fits inside the kettle lip so conducts a lot more heat to the base, but a good kettle is probably easier to find.

[Tony1]

6 minutes ago, TheBiscuits said:

 

That's no good.  Get a decent kettle that doesn't have this design flaw.  Or a round bit of metal that fits inside the kettle lip so conducts a lot more heat to the base, but a good kettle is probably easier to find.

 

Most whistling kettles seem to be designed for gas hobs, and most have the protruding lip underneath, and for their expected use its not a problem.

I can see a few kettles designed for induction/electric hobs on Amazon for about 30 quid, so I could take a punt on one of those. I need one smaller than the normal 2.5 litres though.

It might take a bit of digging to get what I need, and at the moment my heart's not really in it.

 

I have about 5 or 6 brews per day, using about 4Ah per brew, which means I'm using maybe 20Ah daily for the kettle.

Its not a trivial amount, for sure- it probably takes about 15 minutes of engine running to generate that charge, so maybe its costing me 20p of diesel..? 

Plus the wear and tear on the batteries..?

 

So its not ideal, but it certainly is quick, which is what you want when you're after a brew. 

 

For research purposes I've just used the stove to try to boil a mug of water in a saucepan.

After 20 mins the water had reached about 70 degrees, and its not going to get much hotter because the stove top itself is only at about 120 degrees at the moment. Its not that cold outside so the stove is not on full blast. 

 

But the idea of waiting 20 minutes for a brew is just not going to work for me personally.

 

 

[Ronaldo47]

Boiling a given amount of water in a low power kettle could end up  using more energy than boiling the same amount of water in a high power kettle.  The lower powered kettle will be loosing heat by convection and radiaton to the surroundings for a longer time than the high power kettle. On the other hand, if the body of the lower power kettle has a lower thermal mass to be heated up, and a smaller surface area, than the higher power kettle, this could compensate for the longer time that heat is being lost by convection and radiation.  

 

Somewhere I still have one of those Pifco  heaters you could put into a cup to boil just a cupful of water. Haven't seen them on sale for years, they probably don't meet modern safety regulations. 

Edited October 21, 2021 by Ronaldo47
Cup heater comment added, typos

[ditchcrawler]

In the summer we use a 900w electric kettle putting about half ltr in it, two mugs. In the winter the iron kettle sits on the top of the diesel stove, 24/7

[peterboat]

1 hour ago, ditchcrawler said:

In the summer we use a 900w electric kettle putting about half ltr in it, two mugs. In the winter the iron kettle sits on the top of the diesel stove, 24/7

My electric kettle is 1.8 kw for summer use, winter kettle on side of Rayburn boils in seconds on the hot plate 

[Richard10002]

Thanks to everyone for their input. I asked the question because I have a friend who struggles with her "normal sized" electric kettle, (as does my wife), so I was trying to help her find one that is more manageable.

 

I thought normal kettles were about a litre, not 1.7l, so I've learned that.

 

Anyway... lots of small cordless kettles to choose from, so all good. Thanks again.

[TNLI]

If you have a 230V sine wave inverter fitted to your floating pride and joy, it is far more efficient to use a small microwave to heat or boil water. Just measure the required amount into a Tupperware box that you have already drilled a small vent hole in, (Preferably in the top, not the bottom).

 

One health a safety point, 230v inverters are very cheap, if imported from the far east with no manufacturers label in particular. Their power rating in a peak max one, not a continuous rating. The alloy boxed up cheap inverters are NOT EARTHED, and most of them do not have an earth leakage breaker, or even a simple overload fuse fitted. It is not too difficult to fit a separate ELB and an earth wire, as I have done, and I would note that both Fleabay and Amazinzone, will not accept faulty goods as part of their returns policy if the buyer is electrocuted before the item is sent back to the seller!

 

PS: All my Tupperware plastic boxes are cordless, and each one was sold with a tea bag, 2 sugar cubes and some powdered cow included.

Edited November 16, 2021 by TNLI

[cheesegas]

32 minutes ago, TNLI said:

If you have a 230V sine wave inverter fitted to your floating pride and joy, it is far more efficient to use a small microwave to heat or boil water. Just measure the required amount into a Tupperware box that you have already drilled a small vent hole in, (Preferably in the top, not the bottom).

 

One health a safety point, 230v inverters are very cheap, if imported from the far east with no manufacturers label in particular. Their power rating in a peak max one, not a continuous rating. The alloy boxed up cheap inverters are NOT EARTHED, and most of them do not have an earth leakage breaker, or even a simple overload fuse fitted. It is not too difficult to fit a separate ELB and an earth wire, as I have done, and I would note that both Fleabay and Amazinzone, will not accept faulty goods as part of their returns policy if the buyer is electrocuted before the item is sent back to the seller!

 

PS: All my Tupperware plastic boxes are cordless, and each one was sold with a tea bag, 2 sugar cubes and some powdered cow included.

I don’t know about efficiency in terms of heat loss of kettle vs microwave, but non-inverter microwaves with a copper wound transformer are an inductive load with a power factor of around 0.8-0.9. Inverters aren’t very efficient when driving inductive loads, so there’s significantly more losses there compared to a purely resistive load like a kettle. 
 

Inverter microwaves use a switch mode power supply to drive the magnetron tube rather than a big transformer, so they have power factor correction meaning at full blast they’re pretty much power factor 1. 
 

Also, both inverter and non inverter microwaves aren’t terribly efficient. A 1kw output oven will consume around 1.4-1.5kw.