If you have read my articles on power you know I yearn for the days when we get smart power so we have have universal supplies that power everything. This hit home when we got a new Thinkpad Z61 model, which uses a new power adapter which provides 20 volts at 4.5 amps and uses a new, quite rare power tip which is 8mm in diameter. For almost a decade, thinkpads used 16.5 volts and used a fairly standard 5.5mm plug. It go so that some companies standardized on Thinkpads and put cheap 16 volt TP power supplies in all the conference rooms, allowing employees to just bring their laptops in with no hassle.

Lenovo pissed off their customers with this move. I have perhaps 5 older power supplies, including one each at two desks, one that stays in the laptop bag for travel, one downstairs and one running an older ThinkPad. They are no good to me on the new computer.

Lenovo says they knew this would annoy people, and did it because they needed more power in their laptops, but could not increase the current in the older plug. I’m not quite sure why they need more power — the newer processors are actually lower wattage — but they did.

Here’s something they could have done to make it better.  read more »

I’ve written before about both the desire for universal dc power and more simply universal laptop power at meeting room desks.

Today I want to report we’re getting a lot closer. A new generation of cheap “buck and boost” ICs which can handle more serious wattages with good efficiency has come to the market. This means cheap DC to DC conversion, both increasing and decreasing voltages. More and more equipment is now able to take a serious range of input voltages, and also to generate them. Being able to use any voltage is important for battery powered devices, since batteries start out with a high voltage (higher than the one they are rated for) and drop over their time to around 2/3s of that before they are viewed as depleted. (With some batteries, heavy depletion can really hurt their life. Some are more able to handle it.)

With a simple buck converter chip, at a cost of about 10-15% of the energy, you get a constant voltage out to matter what the battery is putting out. This means more reliable power and also the ability to use the full capacity of the battery, if you need it and it won’t cause too much damage. These same chips are in universal laptop supplies. Most of these supplies use special magic tips which fit the device they are powering and also tell the supply what voltage and current it needs.  read more »

Ok, I haven't had a new laptop in a while so perhaps this already happens, but I'm now carrying more devices that can charge off the USB power, including my cell phone. It's only 2.5 watts, but it's good enough for many purposes.

However, my laptops, and desktops, do not provide USB power when in standby or off. So how about a physical or soft switch to enable that? Or even a smart mode in the US that lets you list what devices you want to keep powered and which ones you don't? (This would probably keep all devices powered if any one such device is connected, unless you had individual power control for each plug.)

This would only be when on AC power of course, not on battery unless explicitly asked for as an emergency need.

To get really smart a protocol could be developed where the computer can ask the USB device if it needs power. A fully charged device that plans to sleep would say no. A device needing charge could say yes.

Of course, you only want to do this if the power supply can efficiently generate 5 volts. Some PC power supplies are not efficient at low loads and so may not be a good choice for this, and smaller power supplies should be used.

In furtherance of my prior ideas on smart power, I wanted to add another one — the concept of backup power.

As I wrote before, I want power plugs and jacks to be smart, so they can negotiate how much power the device needs and how much the supply can provide, and then deliver it.

However, sometimes, what the supply can provide changes. The most obvious example is a grid power failure. It would not be hard, in the event of a grid power failure, to have a smaller, low capacity backup system in place, possibly just from batteries. In the event of failure of the main power, the backup system would send messages to indicate just how much power it can deliver. Heavy power devices would just shut off, but might ask for a few milliwatts to maintain internal state. (Ie. your microwave oven clock would not need an internal battery to retain the time of day and its memory.) Lower power devices might be given their full power, or they might even offer a set of power modes they could switch to, and the main supply could decide how much power to give to each device.

Of course, devices not speaking this protocol, would just shut off. But things like emergency lights need not be their own system — though there are reasons from still having that in a number of cases, since one emergency might involve the power system being destroyed. However, battery backup units could easily be distributed around a building.

In effect, one could have a master UPS, for example, that keeps your clocks, small DC devices and even computers running in a power failure, but shuts down ovens and incandescent bulbs and the like, or puts devices into power-saving modes.

We could go much further than this, and consider a real-time power availability negotiation, when we have a power supply or a wire with a current limit. For example, a device might normally draw 100mw, but want to burst to 5w on occasion. If it has absolutely zero control over the bursts, we may have to give it a full 5w power supply at all times. However, it might be able to control the burst, and ask the power source if it can please have 5w. The source could then accept that and provide the power, or perhaps indicate the power may be available later. The source might even ask other devices if they could briefly reduce their own power usage to provide capacity to the bursting device.

For example, a computer that only uses a lot of power when it’s in heavy CPU utilization might well be convinced to briefly pause a high-intensity non-interactive task to free up power for something else. In return, it could ask for more power when it needs it. A clothes-dryer or oven our furnace or other such items could readily take short pauses in their high power drain activities — anything that uses a cycle rather than 100% on can do this.

This is also useful for items with motors. A classic problem in electrical design is that things like motors and incandescent lightbulbs draw a real spike of high current when they first turn on. This requires fuses and circuit breakers to be “slow blow” because the current is often briefly more than the circuit should sustain. Smart devices could arrange to “load balance” their peaks. You would know that the air conditioner compressor would simply never start at the same time as the fridge or a light bulb, resulting in safer circuits even though they have lower ratings. Not that overprovisioning for safety is necessarily a bad thing.

This also would be useful in alternative energy, where the amount of power available changes during the day.

Of course, this also applies to when the price of power changes during the day, which is one application we already see in the world. Many power buyers have time-based pricing of their power, and have timers to move when they use the power. In many cases whole companies agree their power can be cut off during brown-outs in order to get a cheaper price when it’s on. With smart power and real-time management, this could happen on a device by device basis.

These ideas also make sense in power over ethernet (which is rapidly dropping in price) which is one of the 1st generation smart power technologies. There the amount of power you can draw over the thin wires is very low, and management like this can make sense.

Those who travel on trips through many countries face the problem of how to plug in their laptops and gear. Many stores sell collections of adapters, but they are often bulky, and having multiple adapters for multiple gear can be really bulky. (Usually you get one adapter and then use a 3-way splitter or cord for your type of plug.)

Today, however, almost all my travel gear is 2-prong, not 3-prong. It’s mostly my laptop and various chargers for cameras, phones etc. And all of it runs on every voltage and hz found in the world.

It seems if you’re willing to break the rules on rigidity of plugs, one could make a very small adapter by using independent pins, perhaps with a flexible rubber strip handle between them to keep them together and make it safer, but still allowing the pins to bend and have different spacing.

If you do this, there are really just a few types of pins you need. Thin blades, thick blades, thin round pins and in a few places fat round pins. The blades come at different angles — parallel in North America, slanted in Australia, colinear for thick blades in UK. With pins it’s more a question of spacing than angles. A single plug with a way to adjust the spacing could also work. (Israel has a strange pin I haven’t used, I don’t know if other pins or blades could be adapted to it.)

Generally this would not be suitable for plugging a wall-wart into a wall, you would want to plug in a short extension cord with multiple sockets of “your” type. And it might be hard to sell a product like this due to safety standards, since they don’t want to trust the user to know what they are doing, know that they are only plugging in equipment that takes any voltage and doesn’t care what pin is live and which is neutral, doesn’t need ground and doesn’t draw lots of current in any event. But it would be very compact.

I’ve blogged several times before about my desire for universal DC power — ideally with smart power, but even standardized power supplies would be a start.

However, here’s a way to get partyway, cheap. PC power supplies are really cheap, fairly good, and very, very powerful. They put out lots of voltages. Most of the power is at +5v, +12v and now +3.3v. Some of the power is also available at -5v and -12v in many of them. The positive voltages above can be available as much as 30 to 40 amps! The -5 and -12 are typically lower power, 300 to 500ma, but sometimes more.

So what I want somebody to build is a cheap adapter kit (or a series of them) that plug into the standard molex of PC power supplies, and then split out into banks at various voltages, using the simple dual-pin found in Radio Shack’s universal power supplies with changeable tips. USB jacks at +5 volts, with power but no data, would also be available because that’s becoming the closest thing we have to a universal power plug.

There would be two forms of this kit. One form would be meant to be plugged into a running PC, and have a thick wire running out a hole or slot to a power console. This would allow powering devices that you don’t mind (or even desire) turning off when the PC is off. Network hubs, USB hubs, perhaps even phones and battery chargers etc. It would not have access to the +3.3v directly, as the hard drive molex connector normally just gives the +5 and 12 with plenty of power.

A second form of the kit would be intended to get its own power supply. It might have a box. These supplies are cheap, and anybody with an old PC has one lying around free, too. Ideally one with a variable speed fan since you’re not going to use even a fraction of the capacity of this supply and so won’t get it that hot. You might even be able to kill the fan to keep it quiet with low use. This kit would have a switch to turn the PS on, of course, as modern ones only go on under simple motherboard control.

Now with the full set of voltages, it should be noted you can also get +7v (from 5 to 12), 8.7v (call it 9) from 3.3 to 12, 1.7v (probably not that useful), and at lower currents, 10v (-5 to +5), 17v (too bad that’s low current as a lot of laptops like this), 24v, 8.3v, and 15.3v.

On top of that, you can use voltage regulators to produce the other popular voltages, in particular 6v from 7, and 9v from 12 and so on. Special tips would be sold to do this. This is a little bit wasteful but super-cheap and quite common.

Anyway, point is, you would get a single box and you could plug almost all your DC devices into it, and it would be cheap-cheap-cheap, because of the low price of PC supplies. About the only popular thing you can’t plug in are the 16v and 22v laptops which require 4 amps or so. 12v laptops of course would do fine. At the main popular voltages you would have more current than you could ever use, in fact fuses might be in order. Ideally you could have splitters, so if you have a small array of boxes close together you can get simple wiring.

Finally, somebody should just sell nice boxes with all this together, since the parts for PC power supplies are dirt cheap, the boxes would be easy to make, and replace almost all your power supplies. Get tips for common cell phone chargers (voltage regulators can do the job here as currents are so small) as well as battery chargers available with the kit. (These are already commonly available, in many cases from the USB jack which should be provided.) And throw in special plugs for external USB hard drives (which want 12v and 5v just like the internal drives.)

There is a downside. If the power supply fails, everything is off. You may want to keep the old supplies in storage. Some day I envision that devices just don’t come with power supplies, you are expected to have a box like this unless the power need is very odd. If you start drawing serious amperage the fan will need to go on and you might hear it, but it should be pretty quiet in the better power supplies.

I’ve written before about the desire for a new universal dc power standard. Now I want to rethink our systems of household and office power.

These systems range from 100v to 240v, typically at 50 or 60hz. But very little that we plug in these days inherently wants that sort of power. Most of them quickly convert it to something else. DC devices use linear and switched mode power supplies to generate lower voltage DC. Flourescent lights convert to high voltage AC. Incandescent bulbs and heating elements use the voltage directly, but can be designed for any voltage and care little about the frequency. There are a dwindling number of direct 60hz AC motors in use in the home. In the old days clocks counted the cycles but that’s very rare now.

On top of that, most of what we plug in uses only modest power. The most commonly plugged in things in my house are small power supplies using a few watts. Most consumer electronics are using in the 50-200w range. A few items, such as power tools, major appliances, cooking appliances, heatters, vacuum cleaners and hairdryers use the full 1000 to 1800 watts a plug can provide.

So with this in mind, how might we redesign household and office power…  read more »

I’ve called before for a system of Universal DC Power and I still want it, but there is a partial step we could take.

I have a laptop power supply that comes with a variety of tips. The tips tell (through something as simple as a resistor) the power supply how much voltage and current to supply for the laptop they are designed for. I bought mine for use in an airplane, others are sold that do both 12v and AC power.

I would like to see one designed for the corporate market, rather than the carry-around market. Ones to be left in offices and under conference tables, so that when somebody visits with a laptop, they can plug it in. No need to get out their own supply or eventually no need to bring it.

Unlike the carry-around where you pick your tip and leave the rest, this would have an array of tips, possibly rotating on a click-wheel, or all connected to a switch where one can dial the voltage/polarity/etc.

Some companies take more drastic steps. At Google for example, I notice they have standardized on thinkpads, and so all desks and conference tables have think pad supplies. Everybody is able to roam the building and be sure of laptop power. These supplies, while a bit more expensive, could solve the same problem.

An alternate would be to standardize the special tip that describes the power needed. Everybody could get a tip or pigtail for their laptop and carry just that around. Conference rooms could in fact have single supplies that let you plug in several of the pigtail. Of course that is halfway to my original proposal.

Now it turns out a considerable majority of laptops take either 16 volts or 19 volts. The main rebel is Dell, which uses funny plugs and often over 20v. Some need more current than others, I don’t know if any need current limiting or if simply making the PS capable of 100w would do the trick. Anyway, in this case, we could develop a standard 16v plug (the thinkpad one) and a different standard 19v plug (probably an HP one), in two different shapes and colours, and people with laptops could carry a cheap converter to plug their laptop into it. Over time, laptops might come directly able to use this, if they aren’t already — on our path to a smarter power bus. Then people could say, “Oh, you have the orange plug. Great, I can plug my laptop into that.” Vendors who make laptops that won’t plug into one of these two will probably think about switching.

We all would love solar power to work better, but it's hard to have it make economic sense yet, at least if you're near the grid. A solar panel takes 4 years just to give back the energy it took to build it, and it never pays back the money put in if you compare it to putting the money into the stock market. And that's with full utilization. If you use panels and batteries, any time your batteries are near full the power is being discarded, and you also have to replace your batteries every so often and dispose of the old lead-filled ones. Yuk. A grid-tie can use all the power of a panel but that's an expensive, whole-house thing.

But here's a start -- a solar-using PC power supply. My PCs, like many folks, are on all day, including the peak-demand heat of the day. Desktops draw anywhere from 50 to 200 watts, IIRC.

So make a PC power supply that has 3 external connections. One for the wall plug, of course. And two optional ones, one for a 12v solar panel and one for a battery. Then sell it with a 50w or 100w solar panel -- most importantly, the panel should not generate more power than the PC uses.

Because of that, during the bright part of the day, the panel will be providing most, or just barely all, of the power for the PC. The wall plug will provide the rest. At night, the wall plug would provide all the power. It's a grid-tie but it doesn't feed power back to the grid, it just reduces demand on it. The 100w panel takes 100w off the grid load during the peak demand times. And we use every watt the panel generates, we never throw any away.  read more »

I went around and counted that we seem to have around 30 birick and wall-wart DC power supplies plugged in around the house, and many more that are not plugged in which charge or power various devices. More and more of what we buy is getting to be more efficient and lower power, which is good.

But it's time for standardization in DC power and battery charging. In fact, I would like to move to a world where DC devices don't come with a power supply by default, because you are expected to be able to power them at one of the standard voltage/current settings.

One early experiment is on airplanes. I have an adapter that takes the 12v from the airplane, and has many tips which put out different voltages for different laptops. These are expensive right now, but on the right track.

Our other early venture is USB, which provides up to 500ma at 5 volts. Many small devices now use USB for power if that's all they need. There are devices that plug in to USB only for power, they don't use the data lines. Some come with a small cigarette lighter plug that has a USB socket on it for car use. This includes cellular chargers, lights etc.

I think a good goal would be a standardized data+power bus with a small number of standard plugs. One would be very tiny for small devices and only provide minimal USB-level power, a couple of watts. Another would handle mid-level devices, up to a couple of amps. A third would be large and handle heavy duty devices up to say 20 amps, replacing our wall plugs eventually. There might be a 4th for industrial use.

In full form, the data bus would be used for the components to exchange just what power they want and have. Years ago that would have been ridiculous overkill, today such parts are cheap. However, to make it simple there would be a basic passive system -- perhaps as simple as a finely tuned resistor in place of the data components -- to make it easy and cheap to adapt today's components.

A fully smart component would plug into the smart power and get a small "carrier" voltage designed to run the power electronics only. A protocol would establish what power the supply can provide and what the component wants, and then that power would be provided.  read more »