Water boiling, when you have an inverter

[Richard n Ann]

We use a 700-890 w camping kettle when our batteries are full . We boil up a kettle full and save it in a flask for a brew later or even washing up
Similarly when we make a drink using the gas hob any surplus water is saved in a flask ( the type with a pourer). It's just something we do by habbit now.

You can get low wattage thermos kettles, I use one at home. 1L capacity and I think it's about 1200w. When you've finished with it you close the lid and it stays hot.

 

[grasscutter]

We use a 700-890 w camping kettle when our batteries are full . We boil up a kettle full and save it in a flask for a brew later or even washing up
Similarly when we make a drink using the gas hob any surplus water is saved in a flask ( the type with a pourer). It's just something we do by habbit now.

We are with you Jim. We boil kettles and store hot water in flasks when solar permits. Why waste all that electric when the batteries are full.

 

[Barriesimpson]

Only one I can think of is getting a beer out of the fridge once you have put the handbrake on.

And turn the drivers seat around, proves you are not driving any more 'officer'

 

[Jim]

We are with you Jim. We boil kettles and store hot water in flasks when solar permits.

Storing Warm water is OK for washing up, but the water for my Yorkshire Gold needs to be freshly drawn and boiled just the once.

 

[lorger]

Question from a non electrical person, if you use a 900w kettle to boil water for 2 cups of tea. Will this use less overall energy than a 1800watt kettle, my thinking is the 900 will probably take twice as long so assuming your inverter is big enough why go for a low wattage one?

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[Nigel Crompton]

Storing Warm water is OK for washing up, but the water for my Yorkshire Gold needs to be freshly drawn and boiled just the once.

My Navigator stores her water for washing up in the Truma heater; is this not the norm ... ?

 

[Ian_H]

Question from a non electrical person, if you use a 900w kettle to boil water for 2 cups of tea. Will this use less overall energy than a 1800watt kettle, my thinking is the 900 will probably take twice as long so assuming your inverter is big enough why go for a low wattage one?

I think your inverter assumption is probably wrong for some (definately us). But if you could use the bigger one and its minimum allowed volume is low enough, I think it could probably use a little bit less because it will only be losing heat through the sides for half the time.

 

[Jim]

Question from a non electrical person, if you use a 900w kettle to boil water for 2 cups of tea. Will this use less overall energy than a 1800watt kettle, my thinking is the 900 will probably take twice as long so assuming your inverter is big enough why go for a low wattage one?

I'm guessing it's the same or maybe even a bit less. If your inverter can cope, go for the more powerful kettle. I'm always in a hurry for tea. Those 900W ones take forever.

 

[bigtwin]

They will both, to all intents and purposes, use the same amount of energy to boil the same volume of water.

Lower wattage kettles have advantages IF you need to limit the current draw (e.g. on a 4A EHU supply, to stay below the inverter max power, or to stay below the BMS maximum discharge current on a LiFePO4 battery (a 2kW kettle will pull close to 200A from a battery/bank)).

Ian

 

[Lenny HB]

Question from a non electrical person, if you use a 900w kettle to boil water for 2 cups of tea. Will this use less overall energy than a 1800watt kettle, my thinking is the 900 will probably take twice as long so assuming your inverter is big enough why go for a low wattage one?

In theory it would use the same amount of power but in practice the 1800watt kettle will be larger so more metal to absorb the heat so it will use slightly more energy .

We use a small 800 watt mainly for size a 2kw one would be too large in a Motorhome for us.

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[dunnah01]

A five count on the kitchen tap per cup heated in a whistler on the gas ring hasn't been improved on

 

[TheAleMan]

We use a 3kw electric kettle now with this van but, we are looking around now for and induction capable kettle to use in our next van.

 

[jumar]

We have induction hob in our Apartment and a proper induction suited kettle...it's mega fast....
In the van when I've finished my upgrade I will continue to use gas hob for kettle and stainless steel coffee maker... although I will have a portable Induction hob..for other needs...

 

[bigtwin]

We use a 3kw electric kettle now with this van but, we are looking around now for and induction capable kettle to use in our next van.

What size inverter do you have and does it slightly frighten you when you see how much current is being drawn?

Ian

 

[Hoovie]

I'm guessing it's the same or maybe even a bit less. If your inverter can cope, go for the more powerful kettle. I'm always in a hurry for tea. Those 900W ones take forever.

When I had my last Camper I fitted a Multiplus 12/3000/120, so could run anything upto 2400W.
I used to use the 2kW Induction Hob with my "very low quality" ( ) Kettle and found that the perfect setting for making a single cup of tea was actually 400W!
I'd put the kettle on and then by the time got the Mug out, teabag out and in the mug, milk out the fridge and sugar ready, the kettle had just boiled. Perfect

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[Carpmart]

800 or 900w kettle. Whichever one Carpmart recommended.

I use the same one as Caroline and Nick!

 

[Floydster]

I use the same one as Caroline and Nick!

Bit of a pain if you're in different countries...........

 

[Bobbejaan]

Question from a non electrical person, if you use a 900w kettle to boil water for 2 cups of tea. Will this use less overall energy than a 1800watt kettle, my thinking is the 900 will probably take twice as long so assuming your inverter is big enough why go for a low wattage one?

The overall amperage draw will be almost the same for BOTH from "cold to boil" ..... BUT the "Instant Inrush & Intermediate Battery Load" to the vehicle's systems from the Lower-Wattage Unit WHILST each kettle is operating will be less of a "short term shock" to whatever battery (and possibly charging) system you're using.

For example, IF the 1800w kettle draws 200Amp for 5 minutes, the 900w will only draw about 100Amp for 10 minutes, which is less taxing on both the inverter-feed cables AND on the battery bank(s) (especially lead-acid batts).

It also means the batteries potentially can get more "recharge and run support" from the vehicle's Solar whilst the kettle's operating (depending on sun-level), and/or the alternator/B2B if the engine's running.

My apologies if this explanation is not quite as clear as I would have liked to say, but I'm somewhat rough & braindead at the moment.

We use a small 750w kettle as we're never in that much of a rush, and we get exactly 3-Cups or 2-Perfect-Mugs out of it .... which suits both of us mugs "Perfectly"

 

[lorger]

The overall amperage draw will be almost the same for BOTH from "cold to boil" ..... BUT the "Instant Inrush & Intermediate Battery Load" to the vehicle's systems from the Lower-Wattage Unit WHILST each kettle is operating will be less of a "short term shock" to whatever battery (and possibly charging) system you're using.

For example, IF the 1800w kettle draws 200Amp for 5 minutes, the 900w will only draw about 100Amp for 10 minutes, which is less taxing on both the inverter-feed cables AND on the battery bank(s) (especially lead-acid batts).

It also means the batteries potentially can get more "recharge and run support" from the vehicle's Solar whilst the kettle's operating (depending on sun-level), and/or the alternator/B2B if the engine's running.

My apologies if this explanation is not quite as clear as I would have liked to say, but I'm somewhat rough & braindead at the moment.

We use a small 750w kettle as we're never in that much of a rush, and we get exactly 3-Cups or 2-Perfect-Mugs out of it .... which suits both of us mugs "Perfectly"

This explains it great thanks, I did think the smaller one would be less strain on the batteries.

 

[Jim]

This explains it great thanks, I did think the smaller one would be less strain on the batteries.

But that depends upon the size of your bank. Our batteries hardly notice the kettle is on.

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[TheAleMan]

What size inverter do you have and does it slightly frighten you when you see how much current is being drawn?

Ian

We have a 3kw inverter and not bothered in the slightest about current draw. We do have 840ah of lithium at our disposal so that obviously helps Is it not all relevant though as the 3kw boils really quickly as opposed to a 1kw one thats a fair bit slower ?

 

[bigtwin]

We have a 3kw inverter and not bothered in the slightest about current draw. We do have 840ah of lithium at our disposal so that obviously helps Is it not all relevant though as the 3kw boils really quickly as opposed to a 1kw one thats a fair bit slower ?

I don’t doubt the capability of the inverter, or the rest of your system, but a 300A current (which your 3kW kettle will draw) is a LOT of current. It always impresses me when I see currents above 100A!

Ian

 

[TheAleMan]

I don’t doubt the capability of the inverter, or the rest of your system, but a 300A current (which your 3kW kettle will draw) is a LOT of current. It always impresses me when I see currents above 100A!

Ian

TBH, I dont take any notice, I just plug in hit the switch and forget about until it boils. Not very scientific I know, but I don’t scrutinise it all. I will however have a peek next time we have a brew.

 

[Bobbejaan]

But that depends upon the size of your bank. Our batteries hardly notice the kettle is on.

But it's not JUST about the size/capacity of your battery bank, Jim

It can aid and prolong the life of ANY battery bank of ANY size to spread a "specific heavy load" over a longer time at a lower draw-rate, especially when that load can be often repeated throughout the day (for example 100Amp for 10minutes rather that 200Amp for 5 minutes).

As I said in my OP (which your response didn't answer), spreading the load also has the advantage of (a) minimising the Voltage Drop AND Heat Creation in the Inverter Feed Cables. and (b) gives more chance for any Solar and/or B2B system to help the battery bank recover in a smoother & more life-prolonging way, and (c) potentially means you might be able to use smaller-gauge / less-expensive cables (depending on your other electrical devices & usage thereof).

IIRC, it takes about 7 minutes to boil 2-mugs worth in my 750w kettle (even at your 70mph on the motorway example ) ..... We're obviously not as desperate as you to get our next caffeine fix.

The same logic also applies to low-power air-fryers / slow-cook crock pots / etc .

 

[CAB96]

Whistling kettle home and away, it’s the sound that teas nearly ready

Surely it's the sound that (properly brewed) tea is at least 5 minutes away

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[Jim]

....It can aid and prolong the life of ANY battery bank of ANY size.......IIRC, it takes about 7 minutes to boil 2-mugs worth in my 750w kettle (even at your 70mph on the motorway example ) ...

Why use a whopping 750w This is only 135w takes just 25 minutes and must be so much better for your batteries.

 

[eddie]

But it's not JUST about the size/capacity of your battery bank, Jim

It can aid and prolong the life of ANY battery bank of ANY size to spread a "specific heavy load" over a longer time at a lower draw-rate, especially when that load can be often repeated throughout the day (for example 100Amp for 10minutes rather that 200Amp for 5 minutes).

As I said in my OP (which your response didn't answer), spreading the load also has the advantage of (a) minimising the Voltage Drop AND Heat Creation in the Inverter Feed Cables. and (b) gives more chance for any Solar and/or B2B system to help the battery bank recover in a smoother & more life-prolonging way, and (c) potentially means you might be able to use smaller-gauge / less-expensive cables (depending on your other electrical devices & usage thereof).

IIRC, it takes about 7 minutes to boil 2-mugs worth in my 750w kettle (even at your 70mph on the motorway example ) ..... We're obviously not as desperate as you to get our next caffeine fix.

The same logic also applies to low-power air-fryers / slow-cook crock pots / etc .

A: Use correctly spec’d cables of decent quality, voltage drop and heat creation is irrelevant
B: My 220amp Alternator charge’s my Lithium bank via a 120 amp Buck Boost DC -DC charger, an when it’s Sunny 550watts of solar chip in
C: Never “skimp” or cut corners with electrical installations.

My kettle

KETTLE 1.25L - Onyx Black | KitchenAid UK

Kettle 1.25L (5KEK1222) in a dome-style with stainless steel walls. Easy to use with a smooth handle, LED indicator and wide non-drip spout. Choose yours

www.kitchenaid.co.uk

Again as with Jim’s, a nice wide base for stability for motorway brews, essential for a caffeine fix on fourteen hour dashes to the ferry

 

[funflair]

I don’t doubt the capability of the inverter, or the rest of your system, but a 300A current (which your 3kW kettle will draw) is a LOT of current. It always impresses me when I see currents above 100A!

Ian

And then you see cables like this Ian and think OK

 

[Mzracer]

View attachment 946570

And then you see cables like this Ian and think OK

Which are just crazy IMO, wait until there are some high resistance joints building up in some of these installations !!

 

[Jimbohorlicks]

Our small camping kettle is 700 -800w
On my battery app it draws 85 amps peak and the microwave which is 800w also draws a similar amperage ( not both on togther).from a 100ah lithium battery
I have additional lithium batteries to fit which will provide 300ah but I would not want to draw more than the 85 amps so will keep any additional appliances at less than 1000w.
I have enough proper heat sources in the van without adding more through the cables.

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