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Comment: Re:sound idea? (Score 3, Informative) 281

by queazocotal (#49550333) Attached to: Tesla To Announce Battery-Based Energy Storage For Homes

Let's be optimistic, and assume the battery lasts 10 years - 3000 cycles from full-empty.
This is perhaps optimistic.

I am using the numbers for my electricity costs.
These are $.28 or so.
If it's 10kWh, and lasts 3000 cycles, that's 30000kWh.
Or close on $10K worth of electricity stored.

Even with free electricity - it will never break even against grid cost.
Actually having to buy solar panels makes the numbers much worse.

Is it great for off-grid - perhaps. It's a _lot_ more expensive than even spendy lead-acid batteries.

Comment: Re:People with makeup and dyed hair aren't logical (Score 5, Informative) 590

It doesn't work the same as holding your breath.
When you breath a gas containing no oxygen, oxygen streams out of your blood, as it is lower oxygen than the blood, and that is how the blood 'knows' to dump oxygen.
This means that what's coming out of the lungs is largely deoxygenated blood, not oxygenated.
This rapidly causes unconsciousness - much faster than just holding your breath.
It's a not uncommon industrial accident.
You don't really notice it - there is no shortness of breath, you simply feel a bit woozy one breath, and then are unconscious the next, and the next breath may not happen.

Comment: Re:Less accessible (Score 2) 293

by queazocotal (#49503733) Attached to: Norway Will Switch Off FM Radio In 2017

The components used to make a DAB reciever, while they have come down lots in price and power use recently - still use a _LOT_ of power - from the point of view of something running on small batteries. - for example.
4-5 hours on two AA cells.
FM radios (at modest volume on headphones) can last over 200, with the same cells.

Comment: Re:Cut energy use by WHAT? (Score 1) 169

by queazocotal (#49365841) Attached to: Graphene Light Bulbs Coming To Stores Soon

mW= 1/1000th of a watt.
mW=W = parts per 1000 efficiency.

480mW/W = 0.48W of light out for every watt of electricity in.
This is a deep blue LED.
It is very bad if you measure it in lumens per watt because the eye is quite insensitive to blue light.

Whatever the answer - 30%/44% (and you can't do it that way, you've got to integrate over the spectral response of the eye and see if you actually care about colour - green light at 600lm/W is not a functional white light) - is still vastly higher than 10%.

You cannot get the highest efficiency per watt LED bulbs, simply because they would require more LEDs than are absolutely required, and cost more, for no consumer visible benefit other than the watts.

Comment: What they are probably meaning: (Score 5, Informative) 169

by queazocotal (#49363395) Attached to: Graphene Light Bulbs Coming To Stores Soon

The writer of the original article should be shot, hung, shot, and then boiled.

It is riddled with so many inaccuracies that it's meaningless.
'10%' - yes - 10% is mentioned ' Our first devices already exhibit an extrinsic quantum efficiency of nearly 10% and the emission can be tuned over a wide range of frequencies by appropriately choosing and combining 2D semiconductors'
But going from that to LED efficiency is ridiculous.

It is comedically ridiculous to claim that it's going to result in products this year.

It's worth noting that the best existing 'warm white' LEDs bulbs can already produce about twice as much light per watt as compact florescent.
(if they are made with around double the normal number of LEDs and a more efficient power supply).

Comment: Re:Bad idea with current laws (Score 2) 232

by queazocotal (#49048121) Attached to: Iowa Wants To Let You Carry Your Driver's License On Your Phone

You are not required to incriminate yourself.
This however does not mean you cannot be compelled to give physical items,or access to physical items (including fingerprints).
The cops have no right to demand you produce your passphrase.
They have a right to demand the bit of paper they know you wrote the passphrase on.

One can't proceed from the informal to the formal by formal means.