How long would this last?

Crookfilmer · Post by **Crookfilmer** » Sat Jun 10, 2006 11:13 am

If i took a li-ion canon camcorder battery (7.2 V 1850mah)and ran it through the 7805 on a yobo for a nesp WITHOUT a screen (only a tv-out),
how much playing time would i get?

i would do the calculation myself but im not exactly sure of the yobo's amperage and the search function isnt working for me right now

Electric Rain · Post by **Electric Rain** » Sat Jun 10, 2006 6:07 pm

OAC consoles take very little power. I don't know how much current the Yobo uses, but a battery that big should last anywhere from 12-24 hours without a screen. (Am I wrong, guys?)

arfink · Post by **arfink** » Sun Jun 11, 2006 2:07 pm

yeah, that sounds about right. Even a plain old NES mobo (toaster style) will run for about 9 hours on a similar battery. The screen is the real power guzzler, mostly the backlight and the analog/digital conversions.

Post by **Skyone** » Sun Jun 11, 2006 2:09 pm

Er, I'd say 6-8 hours without a screen.

Electric Rain · Post by **Electric Rain** » Sun Jun 11, 2006 2:46 pm

Oh come on... It's an OAC. Say it takes... 100ma. That would last 18.5 hours, wouldn't it?

Post by **Skyone** » Sun Jun 11, 2006 2:55 pm

Yobo's require more than a usual OAC needs. I'd say 300mAh.

Klefmung · Post by **Klefmung** » Sun Jun 11, 2006 2:58 pm

Use a switching regulator for better results. *gaspz0rz*

Electric Rain · Post by **Electric Rain** » Sun Jun 11, 2006 3:07 pm

Yeah, that's probably a good idea...

Post by **CronoTriggerfan** » Sun Jun 11, 2006 4:38 pm

Skyone wrote:Yobo's require more than a usual OAC needs. I'd say 300mAh.

Actually, Yobos only suck about 180mAh, suprisingly! They really are great little units.

CTFan

Post by **Skyone** » Sun Jun 11, 2006 4:39 pm

CronoTriggerfan wrote:
Skyone wrote:Yobo's require more than a usual OAC needs. I'd say 300mAh.
Actually, Yobos only suck about 180mAh, suprisingly! They really are great little units.

CTFan

Damn... that's smooth.

Electric Rain · Post by **Electric Rain** » Mon Jun 12, 2006 12:19 am

Told ya so.

Crookfilmer · Post by **Crookfilmer** » Mon Jun 12, 2006 5:47 am

why would i need a switching regulator instead of the 7805?
is 7.2 volts too close to the drop-off?

Klefmung · Post by **Klefmung** » Mon Jun 12, 2006 10:08 am

A linear regulator also shaves off a little bit of the mah rating of the battery. A switching regulator preserves it better. And there is no dropout.

Electric Rain · Post by **Electric Rain** » Mon Jun 12, 2006 3:40 pm

Yeah, what he^ said. Linear regulators (like the 7805) convert excess voltage into heat.

So, for example, if you were powering a 7805 with 10 volts, it would take 5 volts and send it to pin 3; the output. What happens to the remaining 5 volts? It burns up! Like calories! It leaves the 7805 as heat... thus the reason linear regs usually have to be heat-sinked. So, what it boils down to, is you're losing half of your power.

Switching regulators are far more efficient; they have an oscillator inside them that rapidly switches on and off to magically (I don't know EVERYTHING...) convert the voltage to... well, whatever it's supposed to convert it to. (5 volts, 3.3 volts, 12 volts... whatever. Some of them are "adjustable." These ones require more components, however. Stay away from them if you can.)

DC-DC converters, as I understand them, are just as efficient as switching regulators, but they use inductors to do their dirty work. That's all I know about them...