The Dreamcatcher...Dream Again!!

[hailrazer]

Actually it is correct, current != power.

In most cases, a system run with a lower voltage will consume less power.

No it won't .

A system running on less voltage consumes more power. I have done real life tests on all systems and screens that I have.

Gamecube results :
At 12v the Gamecube draws an average of 1.5A
14.8v will draw 1.2A
11.1v will draw 1.6A
7.4v will draw 2.45A

3.5" DealExtreme results :
At 4.5v it draws around 122mA
At 7.5v it draws around 88mA
At 12 v it draws around 71mA

It's like water running through a pipe. The diameter of the pipe is the voltage, how fast the water is running is the amperage. When the pipe gets smaller the water runs faster. So as the volts go down the amps get faster or go up.

A device takes a certain amount of energy to work, ie Watts. Watts is volts x amps. So if we need 12 watts to get a device to work let's say it is 12v and 1a or 12watts = 12v x 1a. If we lower the Volts to 6v what amount of amps will it draw to get 12 watts? 2 amps. 12 watts = 6v x 2a . Thats how electricity works

This is the reason we use super high voltage AC current for our power lines, less amperage

[daftmike]

A system running on less voltage consumes more power.

Current is measured in Amps, Power in Watts, current != power. The gamecube is a bit of an exception because it uses a complex switching reg, but your own numbers show it uses the same power at 7.4V as at 12V (~1% difference).

For consoles that use linear regs in part of their design, you will save power by using 7.4V rather than 12V. You even give a good example of this with your screen:

3.5" DealExtreme results :
At 4.5v it draws around 122mA
At 7.5v it draws around 88mA
At 12 v it draws around 71mA

At 4.5V it uses 4.5*122 = 549mW
At 7.5V it uses 12*88 = 660mW
At 12V it uses 12*71 = 852mW

Your plumbing analogy doesn't work when describing semiconductor circuits, there is much more going on. Whenever you drop voltage you waste power, the larger the disparity between your supply and the voltage your circuit needs, the more power you waste.

[hailrazer]

The simple fact of the matter is that using a Lower voltage results in a higher current draw. There's no way around it.
Maybe there will be slighy less watts maybe not. Depends on the device. But you will use more amps. Period.

See the problem is that you have people here thinking they can run a Gamecube longer with a 7.4v 5000maH battery than they can with a 14.8v 5000maH battery. When actually it will run half as long.

So keeping it simple is better.

Lower the voltage increase the amps. Simple.

[daftmike]

I don't agree that keeping things simple is better, if people learned the difference between current and power no-one would think a 37Wh battery(7.4*5) had a higher capacity than a 74Wh battery(14.8*5).

However the point made earlier was about the dreamcast, you can power it from 12V with a pico-psu or gc power board, it will then draw about 1500mA from a 12v supply. You can also use 7.4v and a couple of regulators, it will draw about 1900mA from 7.4V.

If you used the dx screen, total draw at 12V=~1571mA, at 7.4V=~1988mA

To give a battery life example, you might use six 2000mAh li-ion cells in your portable. These could be wired 2s3p to make a 7.4V 6000mAh battery or 3s2p for an 11.1V 4000mAh battery.

Both batteries store the same amount of energy but:
the 7.4V battery will run about 6000/1988= 3.02 hours or 181 minutes
the 11.1V battery will run about 4000/1571= 2.55 hours or 152 minutes.

So from the same number of cells you get half an hour or ~20% more battery life using 7.4V rather than 11.1V to power the dreamcast. Simple

[hailrazer]

never tested the. Dreamcast at 7.4v. But as I found out with the Gqmecube the watts were the same at all voltages. Wouldn't suprise me to find the Dreamcast is the same which would make using lower voltage a moot point.
Also doesn't more current equal more heat?

[Klaymator14]

It was Bacteria who found out about the Dreamcast consuming less power at 7.4v, just ask him Oh, and Hail, Bac wants you to join the Racketboy forums, if you want to of course

-Blayke

[daftmike]

never tested the. Dreamcast at 7.4v. But as I found out with the Gqmecube the watts were the same at all voltages. Wouldn't suprise me to find the Dreamcast is the same which would make using lower voltage a moot point.
Also doesn't more current equal more heat?

I couldn't have been more clear in my last post, I have tested this, the dreamcast uses less power at 7.4V than at 11.1V.
In the example I gave above, you would gain 30 minutes of battery life by using a 7.4V battery over an 11.1V of the same "size"(~44.4Wh).

[hailrazer]

yes you were clear. But so was everyone who had "tested" the Gamecube.
Until I test things myself I am skeptical. Which is the proper scientific way right.

[hailrazer]

I know we have gone a bit offtopic here, but I was testing my Psone and got some interesting results.

12v = 550mA
10v = 560mA
8v = 580mA

Seems to be very efficient.

But the screen voltage/amp guide has it as pulling 1000mA at 7.5v which is clearly wrong.
That's why I don't trust others numbers.

But after re-reading this thread I do see your point daftmike. The lower voltage you go the less watts you use. But the lower voltage you go the higher the amperage being used. Sorry for the mistake on my part.

[daftmike]

Of course you're right to check the numbers for yourself, it's because not everyone does that misinformation gets spread around.

I just wanted to point out you'd get a longer battery life running the dc from 7.4V, I think we just got our wires crossed a bit.

[dreamcatcher]

Cool. So I have thought it over, and considering the big 7" shiny 16:9 LCD TFT that needs powering up as well as the DC and the speakers/fan grid I think I am going to go for a battery with more voltage. Having checked out all 12V options (bulky, huge, over a kilo batteries...certainly not very portable...but very appropiate to power a 9kg satelite cellular phone in the middle of the Amazonas when needing rescuing. Anyhow for a portable dreamcast I definitively wanted a smalled pack, so I can overall reduce the thickness of the system -see definition of portable xD I have decided upon 11.V 3800 mAH Li-Po...Amazing specs in a 14x4,8x2cm (aprox. 300 g) pack! This is the latest in high performance LiPo out there. Will post pics when I get them from Germany. I am also going for the picoPSU thing, so I can have a central power supply unit for the Dreamcatcher and easy voltages.

One question regarding Flex Board Connectors, like the small one that connects the laser lens to the gd-rom board...I would like to know if I could find the same ribbon flex, but longer so I can try my idea....Also wondering if these can be bent, or carefully ironed to have a "fold" so to speak. This would make a WORLD of a difference in the interior component design I am planning...Aiming at a 4.3-5 cm total thickness! So, imagine....

Did a little thing on the cover...I know, just perfect- not a very realistic model -imagine joining the ABS hard shell case mechanism to a styrene case....but anyway using the Dcs cover case as the back Gd-Rom cover is cool!!! xD Need to think some other way of protecting/covering the laser...or just keep a game always on it to protect the lens. Hope u like it!

[hailrazer]

One question regarding Flex Board Connectors, like the small one that connects the laser lens to the gd-rom board...I would like to know if I could find the same ribbon flex, but longer so I can try my idea....Also wondering if these can be bent, or carefully ironed to have a "fold" so to speak. This would make a WORLD of a difference in the interior component design I am planning...Aiming at a 4.3-5 cm total thickness! So, imagine....

That's an easy one.Here's what you need :

From http://www.digikey.com" onclick="window.open(this.href);return false;

WM10031-ND --- 4" 16 pin 1.0mm FFC Extension
WM7638TR-ND -- 16 pin 1.0mm ffc connector

Or if you want a 6" extension instead :

WM10057-ND ---- 6" 16 pin 1.0mm FFC Extension


Then just follow one of my guides for extending it :

http://forums.benheck.com/viewtopic.php?f=41&t=33728" onclick="window.open(this.href);return false;


Or since you are not in the USA this might be easier :
http://diy-beamer.com/product_info.php? ... c95938a102" onclick="window.open(this.href);return false;

[dreamcatcher]

Thanks!! That is exactly what I needed...wouldn't have found it in a million years. Although I do remember digikey, I once received their catalog and I swear it was like the nyc phone guide...Do you know if the controller board->motherboard FFC in the Dreamcast is also a 16pin 1mm? It's a rather short flex ribbon and I might need a slightly longer one.

[hailrazer]

No it's a 20 pin 1.0mm ffc.

Here's the connector from Diy-Beamer :
http://diy-beamer.com/product_info.php? ... c95938a102" onclick="window.open(this.href);return false;

And here's what you would need from http://www.digikey.com" onclick="window.open(this.href);return false; :

WM10033-ND -- 4" 20 pin 1.0mm ffc extension
WM5308-ND -- 20 pin 1.0mm ffc connector

[dragonhead]

i would advise against a widescreen dude. dreamcast games look effed up stretched. not to mention, i dont know if that screen can take the 640x480 signal from the DC. if you want it though...

also your concept looks really familiar

http://forums.benheck.com/viewtopic.php?f=6&t=25830" onclick="window.open(this.href);return false;