Talk:Computers

Duty free sales

In Special:Diff/4701248/4703999 Mx. Granger wrote: "not true for Thailand - where is this true?" about

"However, the tax refunds usually require that you don't use the device before leaving the country. Thus this is an option mostly where you stay at a good computer shopping destination before continuing to your destination country."

Duty free shopping#Tax refunding says

"Shops that offer this possibility probably announce the option and help you with the procedure, which may involve getting a special voucher and having the package sealed, to show the item was not used before leaving the country (only goods bought for export qualify)."

This is more or less the same, and if it isn't correct, should be corrected also there.

However, are foreigners really allowed to shop what they need locally without paying VAT (or whatever taxes apply for locals)? My understanding is that tax refunds are specifically for goods to be exported. I have no experience from Thailand, but it seems to be true at least for Finland (the goods must be unused and exported in three months after the purchase).

–LPfi (talk) 08:59, 3 August 2023 (UTC)

In any case, this kind of information should go into the duty free shopping article, as it is not specific to computers, and would be easier to keep up to date in a single article. /Yvwv (talk) 10:34, 3 August 2023 (UTC)

Details should go there, but as this article discusses buying hardware (and should discuss getting software), hinting on the possibility is in scope, with links to Shopping and Duty free shopping (I now added the links). Places that permanently or regularly have favourable offers should also be mentioned, like Thailand now (but is Thailand really the place to go for electronics?). –LPfi (talk) 11:38, 3 August 2023 (UTC)

I bought a laptop in Thailand in 2020 and got a VAT refund when leaving the country, even though I started using the laptop while still in Thailand. There's some information at Thailand#Tax refund - VAT – I think the goods are required to be for export, but they don't have to be sealed and unused at the time they're exported. Meanwhile, Uruguay allows reduced VAT for foreign visitors even for some goods and services that aren't exported (though I'm not sure about computers). The Duty free shopping article says that the procedure may involve having the package sealed, which is less strong language than the text I removed, which says usually and mostly. I'm not an expert and don't know whether the stronger language is accurate, but even if it is I think it's a bit confusing since the example in the previous sentence is Thailand, where this doesn't apply.

Maybe we should rephrase along the lines of "However, check the details of the tax refund requirements: this may only be possible for a device you take out of the country with you, and in some cases it's only possible if you don't use the computer before leaving the country"? —Granger (talk · contribs) 13:49, 3 August 2023 (UTC)

OK. Sounds reasonable. –LPfi (talk) 05:35, 4 August 2023 (UTC)

Tech specs

I removed most of the section Tech specs and instead rewrote as Battery life. Tech specs easily get outdated quickly, so I don't think we want that section. Although this text seemed quite general, such a section will be a magnet for tech enthusiasts, who will quickly make it unwieldy. Also, there were some confused or confusing passages: a dedicated GPU may well be integrated on the mother board or even in the CPU chip, and if you have a graphics card, then it is never integrated, unless I am badly mistaken about the terminology; I don't understand why the AC adaptor would tell anything about the power supply. Hopefully the ones that plan and assemble your laptop will have power needs, power supply and AC adaptor match.

For screen size, I wouldn't recommend the smallest possible. You may well be wishfully thinking that a small one (smaller than a sheet of paper) will suffice, and then be miserable when screen size hinders efficient working.

–LPfi (talk) 07:10, 25 September 2023 (UTC)

wattage

@LPfi:, you removed the passage regarding computer wattage. This is extremely important. Not every voyager is going to have access to AC or grid power. Anyone trying to run a laptop off of a portable power supply or a Solar panel is going to be very upset when they find out that the expensive computer they just bought draws too many watts and trips a shut-off on the portable power supply. Before buying a new computer, you have to make sure that both the wattage and amperage are within the alotments from the portable power supply you plan on using. For example, the Orion Dynamo Pro (a portable lithium power supply of 155 watt-hours) has a power limit of 100 watts whereas laptop AC adapters can often range from about 60 watts to 120 watts. Computers with GPUs or largers screens may require more than 100 watts so you will need a better (i.e. much more expensive) power supply then. Nicole Sharp (talk) 08:23, 25 September 2023 (UTC)

OK. Here it was the terminology that confused me. I assumed "portable power supply" referred to the internal power supply of a portable computer. I assume we need a section on solar power and such portable power supplies. If I get confused, I think many others might be. What's the difference between the portable power supplies and an UPS? –LPfi (talk) 08:33, 25 September 2023 (UTC)

A "portable power supply" is essentially just an external battery. These can range from a small brick that might power a laptop for 30 minutes to very large heavy blocks that can run a laptop for days. The new ones are all lithium but older power supplies are with lead-acid batteries. A portable power supply for a laptop will typically have a built-in AC inverter. GoalZero is a company that sells high-end (i.e. expensive) portable power supplies but these are available more cheaply from many other companies (Jackery, etc.). Most astronomers carry portable power supplies in order to run electronics (robotic telescope, laptop, digital cameras, etc.) out in the middle of nowhere. Nicole Sharp (talk) 08:37, 25 September 2023 (UTC)

A portable power supply can be used as a UPS since most are designed to be able to discharge while charging. The primary difference between a portable power supply and a UPS is that a UPS is designed for indoor use and should not be used outdoors. Additionally, a UPS is typically only designed to discharge occassionally for short periods of time during power outages, and is not designed to provide continuous power for hours on end or for frequent daily use. This is primarily with the battery design since a UPS for short-term use will have cheaper batteries that will wear out faster if they are used frequently and/or for longer periods of time. Portable power supplies are designed for portability: they are lighter in weight if using lithium and will typically have carry handles for larger power supplies so they can be easily carried and transported from site to site. Whereas a UPS is typically heavier and bulkier and will have a long power cable attached since it is designed to be kept plugged into an outlet and not for outdoor field use. Nicole Sharp (talk) 08:42, 25 September 2023 (UTC)  

OK. –LPfi (talk) 08:44, 25 September 2023 (UTC)

You can also run a laptop off of some portable jump starters. The new lithium-based portable jump starters are essentially the same as portable power supplies but just smaller in capacity so won't run a laptop for hours but might get a little bit of extra charge on the laptop battery. A portable jump starter for a car/truck will typically not have an AC inverter built in through so you need an adapter to attach an AC inverter for a laptop. Nicole Sharp (talk) 08:57, 25 September 2023 (UTC)

Vehicular AC inverters may also have wattage and amperage limits that can limit laptop usage in a car without using a portable power supply. Nicole Sharp (talk) 08:57, 25 September 2023 (UTC)

Surge protection needs its own section for laptop safety too. Nicole Sharp (talk) 08:57, 25 September 2023 (UTC)  

Solar power

@LPfi:, you also removed all references to running computers on Solar power, which is just as important as this may be the only source of power for someone in a remote location. Solar panels are pretty inefficient so if you need 90 watts to run the laptop, you should have at least 180 watts in Solar panels. You will again run into power limits though if for example you use a lithium battery as an uninterruptible power supply (UPS) between a Solar panel and the laptop. If the lithium battery has a 100-watt limit then again the computer may not run even if you have 200 watts of Solar panels. Nicole Sharp (talk) 08:27, 25 September 2023 (UTC)

The only mention I find about solar power in your version is "A laptop that requires a high wattage is even worse if running on Solar panels". While the warning was there for a reason, we need more discussion on solar power. We should have at least a paragraph on it, something along the lines of "If you plan on using solar power, do your maths and also check that the specifications; the output needs to suit anything you are going to connect. Solar panels are sensitive for even small shadows and the nominal wattage is not what you will be getting on average. [...]" –LPfi (talk) 08:40, 25 September 2023 (UTC)

portable power

Anything to do with portable power sources (including portable jump starters for vehicles) will likely be better moved onto a separate article page. Discussions on wattage and amperage apply to any electrical device, not just laptops. Portable power sources can include lead-acid batteries, lithium batteries, Solar panels, gasoline generators, etc. Many astronomers for example make their own portable power supplies by adapting marine batteries to run electronics, which is cheaper than buying a professional (pre-made) portable power supply. Nicole Sharp (talk) 09:26, 25 September 2023 (UTC)

Portable power as a general concept might fit Electrical systems. Petrol (or diesel) generators and lead-acid batteries are probably useful only for those moving by own vehicle (car, campervan or small craft). They usually have a battery already, and an engine (on sailing boats: often also wind or solar power) providing power to it. Thus those systems might not require but a mention in passing (local diesel generators are discussed in Electrical systems). Solar power and hand-portable batteries, on the other hand, are relevant to a much wider range of travellers. Wattage and amperage in general are discussed in Electrical systems, but there the focus is on matching what you get from the wall outlet rather than matching your own systems one to another. –LPfi (talk) 09:44, 25 September 2023 (UTC)

I browsed through "electrical systems" and I definitely think that grid/line power should be a completely separate article from portable power. These are two very different situations. Portable power sources are nearly always Direct Current (DC) and have to be adapted to Alternating Current (AC) using an inverter. Whereas grid/line power is nearly always in AC and has to be adapted to DC using an AC adapter. These should not be mixed up and should be on separate article pages. Nicole Sharp (talk) 11:22, 25 September 2023 (UTC)

Feel free to start the article. As long as there are links between the two, people can find what is relevant for them. –LPfi (talk) 14:37, 25 September 2023 (UTC)

 

Portable lithium power supplies are small, light, and compact enough to carry around in a backpack. The USA FAA has a general restriction for all lithium batteries on passenger aircraft to have no more than 100 watt-hours but individual airlines can grant exceptions for larger lithium batteries (including those of 155 watt-hours). Before buying a lithium power supply, you should check the FAA regulations and individual airline restrictions to make sure it is of a flyable energy capacity. A lithium battery of 100 watt-hours is quite small and lightweight and will fit into a purse to carry around and provide enough power to run a laptop of 100 watts for about 2 hours (electronic devices rarely use the full wattage). A larger lithium battery of 155 watt-hours is still fairly small and lightweight and can easily be carried around inside a backpack together with a laptop and other accessories. A power supply of 155 watt-hours might run a laptop of 90 watts for about 3 hours (~2*155/90), plus the run time from the laptop's own internal battery. Nicole Sharp (talk) 11:07, 25 September 2023 (UTC)

The FAA restriction is 100 watt-hours per battery, so you just carry multiple batteries of 100 watt-hours each. These can often be daisy-chained together so you can swap out power bricks while providing continuous power. Nicole Sharp (talk) 11:09, 25 September 2023 (UTC)

Are the restrictions the same elsewhere? One wouldn't want to find out that they aren't allowed when transiting in some overseas hub. –LPfi (talk) 14:39, 25 September 2023 (UTC)