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Slow Electricity: The Return of DC Power? (2016)

lowtechmagazine.com

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Re: Slow Electricity: The Return of DC Power? (2016)

#71

Post by Karrot_Kream »

IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

Low Tech Magazine always writes like this. They always offer some idea which seems interesting on its surface but leaves gaps. They then end the article explaining away the gap with a moral polemic about how we need to change our ways and return to an older way of life. These days I just take the magazine for what it is; a medium containing interesting ideas but overall disingenuous and often impractical.

(Though I do think that Americans uses clothes dryers _much_ more than they should. Most other G20 countries do not. In our household we hang dry any load of laundry that doesn't involve our heavy blankets, and that usually ends up extending the life of our laundry as well, while taking just a few additional minutes. (See, "often impractical" not "always impractical").)

Re: Slow Electricity: The Return of DC Power? (2016)

#72

Post by Karrot_Kream »

ashtonkem wrote: post #55
IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

You do have to wonder if they’re confused on why this isn’t persuasive to normal people. Go cook outside on a rocket stove[0] and washing clothes by hand every day? Come on. Meanwhile the thing that has actually gotten people out of their cars is the ebike. It turns out it’s much more effective to produce a more convenient and comfortable solution for people rather than just demand that they go back a century or two…

> 0 - It’s also telling that such advocates never seem to actually say who should be stuck doing all the labor that machines like washing machines now do for us. Washing clothes and dishes by hand is hard labor, and someone is going to have to give up their career or free time to do it if we’re going to ban these machines. No extra credit if you figure out who will get stuck with the task…

Yeah lol I always find this the funniest part of Low Tech Magazine. While they're always breathlessly moralizing, they rarely think through (or at least write about) the social ramifications of the changes they propose. They do have some interesting ideas though, such as the use of thermal cookers, and burning biomass in a rocket stove may not be the worst idea if you live in an area with a temperate climate and a dirty grid. Perhaps more practical though would be just incentivizing ordering at a restaurant, since a restaurant will be more energy efficient at preparing food than an individual will.

Re: Slow Electricity: The Return of DC Power? (2016)

#73

Post by xxs »

pkulak wrote: post #70
IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

Exactly. The problem here is that everyone will just switch to gas for everything. Dryer, stove, water heater, car, etc. That’s terrible! The 380-volt DC sounded nice, so long as DC to DC is more efficient than AC to DC, but I have no idea if that’s true.

DC-DC actually converts DC to high freq. AC 1st, then uses a transformer and then rectifiers, smoothing, feedback, etc. If no isolation, i.e. common ground is fine, a choke instead of a transformer is fine too.

Re: Slow Electricity: The Return of DC Power? (2016)

#74

Post by lovemenot »

Robotbeat wrote: post #28

So, I used to be "team DC" as well, but after learning up a bit, I realized there are still a lot of advantages to AC in the 21st Century. One reason DC power is more viable nowadays is (as others here have mentioned) the use of DC-DC converters. They internally actually use AC to do the conversion (usually at much higher frequency to save weight and cost on inductive elements). But they're not super cheap (not cheap…

>> With DC, nothing is really at the same voltage, so you need DC-DC converters all over anyway,

This may be the case now, but it's just through historical lack of standardisation, resulting from AC having been the one true standard. It's not inherent to DC.

USB PD is attempting to address this issue. It is standardising voltages for DC-powered devices.

Re: Slow Electricity: The Return of DC Power? (2016)

#75

Post by spoonjim »

dheera wrote: post #42
spoonjim wrote: post #30

I would love 12VDC wired around my house with step down converters for each room. It would allow Our kids to plug in and unplug most of their things themselves (music players, lights, etc).

I'd go for 48VDC. 12V would need some fat wiring to avoid incurring voltage drops for normal amounts of loads. 48V is nice because you can use much thinner wiring, and it's about the highest "safe" voltage to accidentally touch with normal dry skin.

48V would definitely be a big ouch or worse for a kid sticking a wet finger inside or something. 12V is completely safe in all circumstances.

Re: Slow Electricity: The Return of DC Power? (2016)

#76

Post by awesomeusername »

To all the detractors here. I lived on a boat for many years which was 12v only and didn't have the mod cons. You adapt pretty quick then hardly think about it.

So everyone saying how it's fantasy to expect peoples behaviour to change, just remember if you haven't tried it you are likely highly over estimating how much effort it is, and not aware of many of the unexpected advantages.

Re: Slow Electricity: The Return of DC Power? (2016)

#77

Post by SilverRed »

Karrot_Kream wrote: post #71
IlliOnato wrote: post #37

I read the whole article with sympathetic interest, until the conclusion: > One way to solve the problem of high power devices is simply not to use them -- this is the approach that's followed in sailboats, motorhomes and caravans > Obviously, this strategy implies a change in our way of life. It would mean that electricity is used only for lighting, electronics and refrigeration, while non-electric alternatives are…

Low Tech Magazine always writes like this. They always offer some idea which seems interesting on its surface but leaves gaps. They then end the article explaining away the gap with a moral polemic about how we need to change our ways and return to an older way of life. These days I just take the magazine for what it is; a medium containing interesting ideas but overall disingenuous and often impractical. (Though I d…

Not always using a clothes dryer is fine and good advice. But not using an electric kettle and replacing it with heating water on a gas stove is so beyond absurd I'm shocked how they even came to this conclusion since gas stoves are less efficient and much worse for the environment than a kettle.

And a kettle is so low impact anyway. It uses a high amount of power for a very short time and spends almost all of its life turned off. The faster you heat the water the less waste there is as it cools during the heat process.

Re: Slow Electricity: The Return of DC Power? (2016)

#78

Post by Karrot_Kream »

skybrian wrote: post #62

I'm not sure I care whether it's AC or DC, but it might be nice to have some parallel off-the-grid wiring that comes from a solar-charged battery and will run during a power outage. What would work best for this?

This gets complicated and depending on your local regulations, may involve an electrician to certify the work. It's similar to the wiring that goes into adding a generator to your home. If you want something a bit less sophisticated but works nonetheless, you can try to wire solar cells, charge controller, and other stuff to a battery, and then just use the battery directly to power devices. Maybe even have two batteries, one being charged, and one being used. I've had friends do this setup in places where they've been renting.

Re: Slow Electricity: The Return of DC Power? (2016)

#79

Post by SilverRed »

lovemenot wrote: post #74
Robotbeat wrote: post #28

So, I used to be "team DC" as well, but after learning up a bit, I realized there are still a lot of advantages to AC in the 21st Century. One reason DC power is more viable nowadays is (as others here have mentioned) the use of DC-DC converters. They internally actually use AC to do the conversion (usually at much higher frequency to save weight and cost on inductive elements). But they're not super cheap (not cheap…

>> With DC, nothing is really at the same voltage, so you need DC-DC converters all over anyway, This may be the case now, but it's just through historical lack of standardisation, resulting from AC having been the one true standard. It's not inherent to DC. USB PD is attempting to address this issue. It is standardising voltages for DC-powered devices.

Even internally there is no standard. You may put 12V in your user facing input and the device then splits that in to 12v, 5v, 3.5v for all the different components which run at different voltages.

Re: Slow Electricity: The Return of DC Power? (2016)

#80

Post by Robotbeat »

lovemenot wrote: post #74
Robotbeat wrote: post #28

So, I used to be "team DC" as well, but after learning up a bit, I realized there are still a lot of advantages to AC in the 21st Century. One reason DC power is more viable nowadays is (as others here have mentioned) the use of DC-DC converters. They internally actually use AC to do the conversion (usually at much higher frequency to save weight and cost on inductive elements). But they're not super cheap (not cheap…

>> With DC, nothing is really at the same voltage, so you need DC-DC converters all over anyway, This may be the case now, but it's just through historical lack of standardisation, resulting from AC having been the one true standard. It's not inherent to DC. USB PD is attempting to address this issue. It is standardising voltages for DC-powered devices.

But internally, devices operate at different voltages due to fundamental differences in required voltages for their transistors, LEDs, battery cells of different chemistry and charge state, etc. There’s not much getting around it in a strict sense, although standardization can help.
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