Where am I going wrong here?

[coopec]

Some time down the track I'm going to have to buy an inverter to power my 2000W induction hob. I've been doing a bit of research and I came across this. I've been back to the seller (who has 100% feedback rating) and he assures me the price is right. (I notice it is his last one so it has probably been sold by now)



10000W Pure Sine Wave Inverter

 

[AngusMcDoon]

Where you are going wrong is in believing the downright untruthful sales bullsheet. It claims 10 kW from 12 Volts. That's 833 Amps assuming 100% efficiency, more like 1000 Amps in reality. 1000 Amps down some puny cables attached to a battery with crocodile clips - not a chance. Even to get 2 kW from an inverter reliably is going to cost you a lot more than £29.

I suspect your idea of 'research' is reading a few scammy ebay and Amazon listings and believing the crap they write.

 

[AngusMcDoon]

Here's a decent 2 kW inverter. Notice the heftiness and size of the thing and the cost...

Victron Phoenix Inverter 24/2000 Smart 230V

Now can you really imagine that POS you showed doing 5 times what this one does?

 

[coopec]

Where you are going wrong is in believing the downright untruthful sales bullsheet. It claims 10 kW from 12 Volts. That's 833 Amps assuming 100% efficiency, more like 1000 Amps in reality. 1000 Amps down some puny cables attached to a battery with crocodile clips - not a chance. Even to get 2 kW from an inverter reliably is going to cost you a lot more than $53.

I suspect your idea of 'research' is reading a few scammy ebay and Amazon listings and believing the crap they write.

Geez I thought it was 24V (Obviously I need new spectacles).

"believing the downright untruthful sales bullsheet" AND that is coming from someone with 100% feedback rating.

But thanks anyway.

 

[AngusMcDoon]

Geez I thought it was 24V (Obviously I need new spectacles).

"believing the downright untruthful sales bullsheet" AND that is coming from someone with 100% feedback rating.

But thanks anyway.

Well it says 12V and 24V so maybe you do (handy hint - ambiguous and/or non-sensical advertising is a sure fire sign of a scam).

You are fully taken in by the ebay scammers' way of working it seems. Feedback can be bought and falsified, in case you didn't know.

I suggest you get one and try it. It's only £29 from your pocket to the seller's for a pile of junk that does nothing like what it says it does. As usual with your posts, you have decided already. Let us know how you get on running your 2 kW hob. And what you replace it with when you find out you've been scammed and it doesn't work.

 

[Tranona]

Geez I thought it was 24V (Obviously I need new spectacles).

"believing the downright untruthful sales bullsheet" AND that is coming from someone with 100% feedback rating.

But thanks anyway.

Those feedback ratings are nonsense. Do you really think that it means the product is any good and will do what it says when it clearly does not? All it means is that somebody has ticked a box and it could be for a completely different product.

Best to do proper research and understand the principles underlying what the product is about rather than believe a ticked box.

As said drawing 2KW off a 12 or 24V battery is a huge number of amps which requires heavy duty wiring and a big bank

 

[PaulRainbow]

If you could find a genuine 10kw inverter @24v, which i doubt exists, at that size they are, in my experience, 48v, it would need cables of about 200mm sq!!

It would cost a few thousand.
It would be BIG.
It would be heavy.
It would, at max output, suck 500a from a 24v battery. That's 1000w of LA batteries flat in an hour. 1000w of batteries at 24v is 20 x 100ah 12 batteries wired in series/parallel.

 

[PaulRainbow]

A decent rule of thumb with inverters (assuming good quality) is for every 100w of 240v power out you need to put 10a of 12v DC in, halve the input amps for 24v.

So, a 2kw inverter will draw 100a @ 24v. It will require 35mm cables, if the cables are kept short. It will take 200ah of 24v LA batteries to 50% DOD in 1 hour. That's 4 x 100ah 12v batteries.

A 2kw inverter is not suitable for a 2kw induction hob.

 

[dunedin]

If you could find a genuine 10kw inverter @24v, which i doubt exists, at that size they are, in my experience, 48v, it would need cables of about 200mm sq!!

It would cost a few thousand.
It would be BIG.
It would be heavy.
It would, at max output, suck 500a from a 24v battery. That's 1000w of LA batteries flat in an hour. 1000w of batteries at 24v is 20 x 100ah 12 batteries wired in series/parallel.

Quite right.

It is amazing how many people seem taken in by YouTube videos etc and think they can go electric without doing even the very basic maths ! Power = Volts x Amps is a good place to start.

A gas cooker would be a good backup for any boat going offshore, even if alongside an induction hob as well.

PS. At risk of thread drift, another emerging common area of people “failing to do the maths” is people fitting Battery to Battery (B2B) chargers for charging big LFP battery banks. These can generate huge heat when doing high rates of charging. Intersting / scary pictures of some of these chargers using infra-red cameras - and these were of well known quality marine brands, not eBay cheapos.

 

[Kelpie]

My original inverter was 3kw/12v and cost about £400. It lasted a year
Now replaced by a big blue one at more than double the cost...

 

[ylop]

I think many poor quality advert or product specs like this (same with batteries quoting amazing Ah capacities) are actually quoting mW or mA perhaps through stupidity, more cynically so if anything every comes of it they can just say it was a simple typo.

 

[davidej]

I wonder if the eBay seller has entered one too many noughts.

1000 watts maybe?

 

[[194224]]

Do any of the positive feedback comments refer to anything even remotely like the inverter? Faux pampas grass plant, elastic ribbon, tether straps, oh and a USB charger cable. At least that one has something to do with electricity. The good news is that the "last one" still seems to be for sale.

Edit - assuming of course we're looking at the same seller as in this link

The only one I can see selling this device and with a 100% feedback score and a name starting with "yi" (visible in the first post).

 

[thinwater]

Before you go down any electrical rabbit hole you need to understand electricity and batteries. You could either burn your boat down or have it just not work.

2000W is about 200 Ah, byt the time you look at losses in the inverter and the battery. That is 3-4 batteries taken as low as they should practically go all by itself. It simply is not practical to cook with elelctric unless you have a massive bank, lots of recharging (about 400W of solar, just so you can cook for 1 hour, plus your other solar) and really understand how you are going to power this.

Propane or alcohol. Even alcohol will be more usable.

[I'm guessing the 10,000 W inverter was a 1,000 W misprint, and probably junk at that. I've had a 2000 W inverter, and it was a big, heavy package with big cables. Think like a small welding machine, since that is the amount of power you are taking about.]

 

[RJJ]

Before you go down any electrical rabbit hole you need to understand electricity and batteries. You could either burn your boat down or have it just not work.

2000W is about 200 Ah, byt the time you look at losses in the inverter and the battery. That is 3-4 batteries taken as low as they should practically go all by itself. It simply is not practical to cook with elelctric unless you have a massive bank, lots of recharging (about 400W of solar, just so you can cook for 1 hour, plus your other solar) and really understand how you are going to power this.

Propane or alcohol. Even alcohol will be more usable.

Broadly agree. You're also constrained by the discharge ability of your house batteries unless you specifically optimise them for this sort of (ab)use.

Our experience with small portable induction hob (as addition to our standard gas stove) was it was great on shorepower, but otherwise a struggle on the batteries. The main benefit was keeping heat out of the yacht, rather than saving gas. We had 320W of solar powering a nominal 1500/3000W inverter from 3x150Ah AGM batteries.

Typically we could use the induction to make porridge at any time, or boil a small kettle (2 cups) on a low setting. With the sun directly overhead helping maintain the voltage, we could bring a medium saucepan to the boil (but not keep it there).

Friends that actually cooked using electric / lithium batteries/solar had put a LOT of thought, effort and money into it. They had 3000W of solar and 1200AH of lithium if I remember right.

 

[PaulRainbow]

Before you go down any electrical rabbit hole you need to understand electricity and batteries. You could either burn your boat down or have it just not work.

2000W is about 200 Ah, byt the time you look at losses in the inverter and the battery. That is 3-4 batteries taken as low as they should practically go all by itself. It simply is not practical to cook with elelctric unless you have a massive bank, lots of recharging (about 400W of solar, just so you can cook for 1 hour, plus your other solar) and really understand how you are going to power this.

Propane or alcohol. Even alcohol will be more usable.

I think you must mean amps, not amp/hrs ?

[I'm guessing the 10,000 W inverter was a 1,000 W misprint, and probably junk at that. I've had a 2000 W inverter, and it was a big, heavy package with big cables. Think like a small welding machine, since that is the amount of power you are taking about.]

Look on Ebay and Amazon, thousands of 20,000w inverters advertised, all junk.

 

[AngusMcDoon]

Before you go down any electrical rabbit hole you need to understand electricity and batteries...

2000W is about 200 Ah...

Watts and Ah are not the same thing. The former is a rate of energy flow in Joules per second, the latter an amount of charge where 1 Ah is 3600 Coulombs.

Perhaps what you meant to say is '2000 W from an inverter requires about 200 A input at 12 V'.

 

[Kelpie]

We cook electric around 85% of the time. 730w solar, plus another 200w deployed on deck when necessary. It works well but as has been said it's a big project.

If you only need to run a 2kw load occasionally, it's probably easier and cheaper to use a suitcase generator.

 

[AngusMcDoon]

I wonder if the eBay seller has entered one too many noughts.

1000 watts maybe?

Don't think so, it's just plain old ebay fraud, like the 2 TByte USB drives sold for a few dollars and the MPPT solar controllers that aren't. The 10,000W is in the image as well as the text.

Amazon and ebay don't give a hoot about the veracity of the crap that's sold on their sites claiming that they are just a platform and not the seller, and the gullible get taken in by the feedback score.

 

[AngusMcDoon]

With the sun directly overhead helping maintain the voltage, we could bring a medium saucepan to the boil (but not keep it there).

Keep the saucepan on the boil, or the sun directly overhead?

Friends that actually cooked using electric / lithium batteries/solar had put a LOT of thought, effort and money into it. They had 3000W of solar and 1200AH of lithium if I remember right.

Exactly. Some fraudulent crap from ebay for £29 is just not going to do it, but here's guessing that Coopec will ignore everyone and go ahead anyway. Perhaps as a comparison he should look at this 48 V 5 kW model (so a quarter of the input current required from his 10 kW POS). It costs 65 times the price, and is a hefty beast at 30 kg...

Victron Phoenix Inverter 48/5000 230V