Trying to power this kettle

[chrisgoddard2021]

I have this converter that pulls out 2000 W
Converts 12 V to 240
But I have a problem. I’m trying to run something that is more powerful than this like a kettle. What is 220 to 240 1500w can this be done? And if so, what do I need to step up or step down the power?

 

[PaulRainbow]

I'm confused.

The water boiler in your pic is rated at 1500w, the inverter is rated at 2000w, so it should run it.

You also mention a kettle, which is usually 3000w, so the inverter will not run it. Best option for a kettle would be to get a 1000w kettle.

What batteries do you have ?

 

[Ian_Edwards]

Although the inverter is rated at 2kW, and the kettle at 1.5kW, the initial inrush of current is probably a lot more than the steady state current of a 1.5kW kettle. The resistance of the kettle element will be a lot lower at ambient temperature, than when running hot. ie the element will have a positive resistive temperature coefficient.
I have a 3kW Victron inverter charger backed by 5kWh of LiFePO4, and that won't start a 2kW kettle.
The problem was solved by buying a Robertson 800W kettle and I can run that with a 1kW immersion heater and a 800W micro wave providing I don't start them all at the same time. But that's drawing around 240amps at approximately 12volts, so I don't do that for more than a few minutes whilst I boil the kettle and make my porridge , first thing in the morning.
So the answer is buy a lower power kettle, there are a few on the market aimed at campervans and caravan owners. It'll take a little longer to boil, but save a lot of gas.

 

[PaulRainbow]

Although the inverter is rated at 2kW, and the kettle at 1.5kW, the initial inrush of current is probably a lot more than the steady state current of a 1.5kW kettle. The resistance of the kettle element will be a lot lower at ambient temperature, than when running hot. ie the element will have a positive resistive temperature coefficient.
I have a 3kW Victron inverter charger backed by 5kWh of LiFePO4, and that won't start a 2kW kettle.
The problem was solved by buying a Robertson 800W kettle and I can run that with a 1kW immersion heater and a 800W micro wave providing I don't start them all at the same time. But that's drawing around 240amps at approximately 12volts, so I don't do that for more than a few minutes whilst I boil the kettle and make my porridge , first thing in the morning.
So the answer is buy a lower power kettle, there are a few on the market aimed at campervans and caravan owners. It'll take a little longer to boil, but save a lot of gas.

Op refers to a kettle, but the pic is for a 10l water heater.

I'm surprised your 3kw inverter will not cope with a 2kw kettle, what size cables do you have from the batteries to the inverter ?

 

[William_H]

The rating of an inverter is obviously best conditions in laboratory. In real life as Paul says the difficulty is getting enough voltage at the high current to the inverter. Need big batteries very heavy wiring and high current switches fuses etc.
Also as said initial current can be much higher when switching on. So as said need lower powered kettle or bigger inverter. What you really need to feed an inverter is a 24v system. (1/4 the current for same power) ol'will

 

[Neeves]

The rating of an inverter is obviously best conditions in laboratory. In real life as Paul says the difficulty is getting enough voltage at the high current to the inverter. Need big batteries very heavy wiring and high current switches fuses etc.
Also as said initial current can be much higher when switching on. So as said need lower powered kettle or bigger inverter. What you really need to feed an inverter is a 24v system. (1/4 the current for same power) ol'will

The problem is that most yachts are wired for 12v, windlass and powered winches. So to use the kettle you need to change... the lot.

Few of us can buy a new yacht, off the plan, and specify 24v - 24v might better but the reality is we have a 12v systems needing 12v solutions (or it turns out to be an expensive kettle .

Fortunately 4x4s, caravans, motor homes are largely 12v (I don't actually know this - I'm making it up) so we need to give chandlers a miss and go visit 'camping' stores.

'Most' camping kit does not enjoy the standard 'Marine' surcharge.

Jonathan

 

[Ian_Edwards]

Hi Paul,
I don't know the size of the cables from the battery to the inverter, the boat is 165miles away so it's not easy to check.
The inverter runs 2.6kW without too much of a voltage drop, so the cable size can't be too far off.
Don't underestimate the use of a positive coefficient of temperature in the design of water heaters in general. They are designed to self limit the maximum power the element can take, and prevent thermal run a way. This part of the design combined with a thermal fuse in series with the element helps make the heating element safe, and prevent fires.
The 2kW (or whatever) rating will be when the kettle is hot. It's likely to be higher when it's cold.

 

[Alex_Blackwood]

Although the inverter is rated at 2kW, and the kettle at 1.5kW, the initial inrush of current is probably a lot more than the steady state current of a 1.5kW kettle. The resistance of the kettle element will be a lot lower at ambient temperature, than when running hot. ie the element will have a positive resistive temperature coefficient.
I have a 3kW Victron inverter charger backed by 5kWh of LiFePO4, and that won't start a 2kW kettle.
The problem was solved by buying a Robertson 800W kettle and I can run that with a 1kW immersion heater and a 800W micro wave providing I don't start them all at the same time. But that's drawing around 240amps at approximately 12volts, so I don't do that for more than a few minutes whilst I boil the kettle and make my porridge , first thing in the morning.
So the answer is buy a lower power kettle, there are a few on the market aimed at campervans and caravan owners. It'll take a little longer to boil, but save a lot of gas.

I see what you are saying but I would not have thought that the inrush current from a resistive load such as a kettle would make much difference. If it had been inductive then yes. Not saying never, but! Also don't want to start a mile long thread on inrush currents
+1 for Pauls input.

 

[steveeasy]

Big kettle. Must drink a lot of tea.

Steveeasy

 

[fredrussell]

... What you really need to feed an inverter is a 24v system. (1/4 the current for same power) ol'will

Would it not be 1/2 the current for the same power?

 

[PaulRainbow]

Lots of low wattage kettle on the market. We have this one, it's nice quality : Quest Rocket 1.8L Stainless Steel Kettle - Cream

Quest make several different models : Quest low wattage Kettle - Google Suche

 

[PaulRainbow]

Would it not be 1/2 the current for the same power?

Indeed it would.

A 2kw device powered by a 12v inverter will draw 200a, if connected to a 24v inverter it draws 100a.

 

[Graham376]

Although the OPs inverter label says 2000w, is that constant load?

Our inverter is labelled 3000w but that's peak power. Constant load is only 1500w.

 

[ylop]

Although the OPs inverter label says 2000w, is that constant load?

Our inverter is labelled 3000w but that's peak power. Constant load is only 1500w.

His inverter looks a lot like the cheap tat available on eBay etc for £30 which make ambitious power claims but are supplied with crocodile clips or even cigarette lighter adapters. If he does manage to power his urn (giant kettle) from it - he might be in for a shock how much power it will use…. I think he’d be lucky to still have any usable power in a 120A lead acid battery by the time it boils…

 

[oldharry]

You will need substantial batteries and charging facitlies to run a 3 kw kettle from a 12v source. The draw on the batteries will be around 200 amps, which even with modern lithium types is quitea lot. The wiring of course must be up to carrying that sustained load

 

[PaulRainbow]

You will need substantial batteries and charging facitlies to run a 3 kw kettle from a 12v source. The draw on the batteries will be around 200 amps, which even with modern lithium types is quitea lot. The wiring of course must be up to carrying that sustained load

A 3kw kettle will draw 300a through an inverter !

 

[steveeasy]

10 litre kettle. I wonder how long it would need to run to heat that amount of water ?. I’ve a nice mug that plugs in to my 12 v socket that boils the water in 2-3 mins. No inverter needed. Ideal when I don’t want to be down below whilst trying to sail.

Steveeasy

 

[Sea Change]

The rating of an inverter is obviously best conditions in laboratory.

My 3kva Victron is rated for 6kva peak. But it's possible that cheap units are a bit less honest with the figures.

 

[oldharry]

My 3kva Victron is rated for 6kva peak. But it's possible that cheap units are a bit less honest with the figures.

Possible = true. Not just a 'bit less' honest - complete fabrication. Run them at the claimed maximum most go bang in a very few minutes. The quoted 'peak load' is almost invariably a theoretical absolute maximum the circuitry ought to be capable of. A bit like cheap audio gear claiming a peak power out of 200 w from a 10 watt amp....

Theres also the question of the output waveform. Its vastly cheaper and simpler to produce a simple 'on/off' square waveform for the a/c output Doesnt matter for a kettle or other heating element, but a lot of a/c electronics require a true sine wave form supply. Putting a square or even stepped a/c wave form into almost any modern electronic gear can damage or destroy it instantly. USB chargers are particularly vulnerable, creating a potential fire risk if the voltage regulator fails.

And before anybody jumps, I have seen it happen. The voltage regualtor chip failed allowing significant overvoltage to be applied to the lithium batteries. They go off with a very satisfactory bang - as long as its not in your workshop or boat.....

 

[PaulRainbow]

We have a 3000w Victron Multiplus 2 (inverter/charger) that's set to run the whole boat as default. It is connected to shore power, but the input is ignored unless the battery SOC falls below 50%, because i want the most solar yield that's available. Anyway, the point is, the inverter happily runs all of the 12v/24v system and the 240v stuff as well. That includes induction hob, combination microwave, kettle, TV etc etc, plus USB chargers and all navigation electronics. You pays your money........