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I want to buy a AC voltage converter for frequent international travel with some small appliances, and should support step up and down between 110V and 220V; found this one https://amzn.to/2voExKD is portable but it supports max 100 Watts only, then found this one https://amzn.to/30UKV8b supports up to 2000 watts but it weighs 30 lbs very bulky not convenient to carry on to flights; then found this one https://amzn.to/2U7FDF1 supports up to 2300 watt and lightweight to carry, but it supports step down from 220V to 110V only, not the step up;

so I wonder is it possible to make a product that

  1. support both step up/down AC voltage converter, between 110V and 220V;
  2. support large power consumption up to 2000 watts ideally;
  3. also being lightweight and portable, easy to carry to flight check-in luggage? (less than 3lbs, or as small as possible)

Update: I edited a little bit to be clear I wish to see a product has all the 3 features, especially large power appliances (like 1500 w induction top cooker), not only laptop/phone charger which I know that takes 100-240V variant AC input;

Thanks;

If not, could someone tell the rationales why can't make a product with all above 1 & 2 & 3 features?

If can only choose 2 features out of the 3, I would possible choose this https://amzn.to/2U7FDF1 supports up to 2300 watt and lightweight to carry, and one-way only step down from 220V to 110V; why I am not seeing a step-up only product? Is step-up harder to make than step-down only? which one of the step up/down is more energy efficient, and less energy loss inner heat dissipation?

I like to hear some in-depth answer about rationales behind step-up and step-down; that can explain why

  1. the first product https://amzn.to/2voExKD is lightweight/portable but supports max 100 Watts only
  2. the second one https://amzn.to/30UKV8b supports up to 2000 watts for both step up and down between 220V <=> 110V, but why it weighs 30 lbs why it needs to be made so bulky, is it related to heat dissipation? how much energy loss if this is really working at 2000 watts;
  3. the third one https://amzn.to/2U7FDF1 supports up to 2300 watt step down from 220V to 110V only, it's lightweight to carry, Weight:1.3lb, is it because step-down is easier to make than step-up AC transformers? Does step-down only converters have better energy efficiency? Nearly no heat dissipation, Or 100% energy conversion? Is that the reason why it can be made so small (Weight:1.3lb)?

Thanks again;

TomasJ
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  • "but it supports step down from 220V to 110V only, not the step up;" Your logic is flawed. It does step up from 110V to 220V. It's written write on the product: "Step up & down transformer". And it's big because it has to be to stop the iron core from saturating when the frequency is so low at 60Hz. If it was a higher frequency it could be smaller. Analog: To produce the same amount of power you can either push infrequently very very hard, or very frequently very very lightly. – DKNguyen Jan 25 '20 at 22:29
  • Tomas, Are you looking for something that will convert any mains supply to work with any device designed for any other mains supply? In other words, do you want to be able to use a 120 VAC mains and produce from it 220-240 VAC mains for use with devices needing that.... and also want to be able to use a 220 VAC mains to produce 120 VAC, also? So that you can buy stuff from any one country and then always be able to use it in any other country you visit? (That "dual channel voltage converter" feature in your first link?) – jonk Jan 25 '20 at 22:38
  • If the highest priority device is a laptop, then those power supplies can usually cope with both 110 and 230. – Solar Mike Jan 25 '20 at 22:52
  • The traditional way is to use "heavy iron." For a converter based on a simple transformer I seem to recall the approximate "20 watts per pound" as a guide for transformers that use cheap materials. Using the really good stuff for the core and best practices for wiring this can be cut in half. So I'd expect about 50 pounds for a 2 kW transformer, if it uses advanced materials and is well designed. It will likely cost several hundred dollars, too. – jonk Jan 25 '20 at 23:11
  • Just to say, I've personally tested the 100W step-up/down converter (SW-S12) and it does the job right, as long as you select correctly the switch in the back. You only need an adapter for 220V which isn't included. – Natsu Kage Jan 25 '20 at 23:31

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I will try to answer your questions the simplest way possible:

A step up converter is almost always an iron-core based transformer. enter image description here

Simply because it's the simplest and most cost effective. A transformer easily converts 110V into 220V, or the reverse, at 60hz without any circuitry. The only problem is that transformers are big and bulky. A 500W transformer will weigh in excess of 5 pounds. A 2kW+ over 30lb. This is indeed because of heat dissipation and thermal constraints due to efficiency. The more powerful, the more power lost, so the bigger the transformer needs to be.

A step down converter is actually a very simple product. It has very little weight because there is no transformer.

enter image description here

Source: https://www.homemade-circuits.com/how-to-make-220v-to-110v-dc-converter/

This simple circuit can easily handle 2000W because it simply needs to lower the voltage. There is basically no loss at 15A maximum.

The issue with dual step up/down converters right now is that there is no cost effective way of converting 110VAC to 220VAC without using a transformer. There exists such products, but they are highly complicated and cost a fortune and isn't much smaller than a transformer of the same power capabilities. Someone correct me if they find one that is less than a few thousand dollars...

I did see actual papers on making a product like you want:

https://www.researchgate.net/publication/277673392_Single-phase_direct_AC-AC_boost_converter

Not sure if it is consumer available yet.

Natsu Kage
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  • thanks, then how is the 1) the first product https://amzn.to/2voExKD made to do both step up and down 110v <=> 220v? It's cheap and lightweight/portable but why supports max 100 Watts only? Is it the same iron-core based transformer ? Can the same technology be used to make for a larger power and still being portable, like 200w? or what's the max limit of same technology? – TomasJ Jan 26 '20 at 02:30
  • The first product is iron-core based. It's a little on the heavy side but easily transportable. The reason it is step-up/down is because the circuit has a switch which exchanges the sides of the transformer. The same technology is used for all step-up/down converters. Like this 300W one https://www.amazon.ca/LiteFuze-LC-300US-300Watt-Voltage-Converter/dp/B00BQ0FQ4S/ref=sr_1_8?keywords=step+up+500w&qid=1580020757&sr=8-8 up to this 2kW one: https://www.amazon.ca/Voltage-Transformer-2000W-Power-Converter/dp/B07CCLSXJB/ref=sr_1_5?keywords=step+up+2000w&qid=1580020786&sr=8-5 – Natsu Kage Jan 26 '20 at 06:40
  • Just to answer your question: The reason it only supports 100W is because it uses a very small transformer that is not big enough to support more than 100W. Any more than 90W constantly will make it overheat and fuse thermally. – Natsu Kage Jan 26 '20 at 07:02
  • Thanks again; may you also answer my other question https://electronics.stackexchange.com/q/477953/240946 why can't find a DC-to-AC inverter product to dual voltage 110V and 220V in a single inverter? is it technical difficulty (hard to make)? or just being unpopular (may be able to DIY a dual 110V 220V voltage inverter)? or otherwise will buy the 220V inverter, and this step-down only converter, to get both 110V 220V output? – TomasJ Jan 26 '20 at 10:36