I am travelling from Hong Kong to Ireland. In Hong Kong type G (220V, 50Hz) plugs and sockets are used. While the plugs and sockets in Ireland are also type G, they have different voltage (230V, 50Hz). Just wondering if I can use my Hong Kong chargers without using a adaptor in Ireland.
Mains power is not like a precise lab instrument with strict voltage ranges. The European Standard EN50160 (this is a draft, the standard is an expensive download) for example prescribes +-10%, the UK standard prescribes +10% -6% in the power supply (search for "frequency and voltage at supply" in the standard without quotes) so 230V in reality is a wide range of 207-253V. Your 220V device will be just fine, it is usually built to much wider tolerance. Europe have standardized from 220V-230V-240V systems to 230V around 1990-2000 and there were no widespread problems.
Most chargers are 110V-240V anyways where the numbers are the "middle" of the voltage range anyways. It's not like 241V will immediately burn out a 240V device.
The only time a typical traveller realistically have a voltage problem is when you have a heating element and even then only between 110V and 230V systems. I have destroyed a dual voltage kettle by forgetting to switch it from 110V to 230V.
Well, I can lend you my experience living in a somewhat rural town, less than 300m from the power plant and right next to a factory.
I'm Italian, so the nominal voltage would be 230V at 50Hz.
First off, being so near to the plant most of the time the line voltage was closer to 250. I've even seen 260 on a few occasions.
But then there's the factory. Sometimes the lights would dim so significantly that it took your eyes a few seconds to adjust - right at the same time I could hear heavy machinery spooling up next door.
I checked the voltage a few times out of curiosity and I've seen it go all the way down to 190V.
Give it 10 seconds for the power plant to adjust output and everything went back to normal.
I haven't noticed electronics failing more often than normal or anything like that.
Your charger is going to be fine.
I live in Ireland and was in Hong Kong earlier this year - I had no problem doing it the other way. I can't say for certain, but I'd be very surprised if it proved problematic.
This isn't a direct answer to your specific question, but here in Australia, mains power is 240v, and I've seen many appliances labelled with voltages ranging anywhere from 210v to 255v which work without any problems. It's also quite common to see ranges like 220v-240v and 220v-250v on appliances sold in Australia, for use with our 240v power supply, probably because most appliances aren't manufactured in Australia, but imported from countries that presumably also export to other countries with different voltages. I don't think it needs to be exact, but you would definitely run into problems where the ratio is closer to double, like using 110v instead of 220v or vice versa.