runtime revelation - which do YOU think is better?

dhabell · Jan 22, 2010

i plan on using the following driver http://www.dealextreme.com/details.dx/sku.15880

which would give me longer runtime? 3 AA's or 2 C's ?

I tried to use one of those runtime "calculators" but I think I was doing something wrong.

Black Rose · Jan 22, 2010

Are you using a parallel or serial battery configuration?

Also, are you using alkaline cells or NiMh cells?

Black Rose · Jan 22, 2010

dbl post

The Dane · Jan 22, 2010

Alki's or NiMh's?
Nah either way 2 C's will have more capacity than 3 AA's
Example:
3 x 2200mA NiMh's = 3.75V x 2200mA = 8.25Wh
2 x 5000mA NiMh's = 2.5V x 5000mA = 12.5Wh
Or @50% increase.

dhabell · Jan 22, 2010

Black Rose said:
Are you using a parallel or serial battery configuration?

Also, are you using alkaline cells or NiMh cells?

oops sorry.

series and ordinary alkaline

45/70 · Jan 22, 2010

I'm no expert, for sure. I'm not sure if that circuit is a "buck/boost", or more than likely, just a "boost" circuit, that is direct drive when the voltage is above the Vf of the LED. In either case though, having to always boost the voltage of 2 "C" cells would take some of the "sting" out of their superior Wh, whereas the 3 "AA" setup would require less (or no) boost and close the gap in an efficiency comparison.

Dave

The Dane · Jan 22, 2010

Alki's makes this a no brainer!

2 x C

1000mA is a high drain for a AA cell and therefore the therotical capacity of @3000mA wil drop to under 1000mA. A C cell with a therotical capacity of @8000mA wont sag as mush and therefore deliver more of its capacity before dying.

45/70 · Jan 22, 2010

The Dane said:
Alki's makes this a no brainer!

2 x C

1000mA is a high drain for a AA cell and therefore the therotical capacity of @3000mA wil drop to under 1000mA. A C cell with a therotical capacity of @8000mA wont sag as mush and therefore deliver more of its capacity before dying.

Yeah, you have a very good point there, Dane! :thumbsup:

I'm just not into thinking "alkaline" anymore. Never use them.

Dave

Magic Matt · Jan 22, 2010

If somebody addicted to flashlights is a flashaholic.... is somebody addicted to alkalines an alkaholic?

paulr · Jan 23, 2010

Heh, I recognize the microprocessor on that board. I wonder if it is running FluPIC code and if DX got it legitimately from Goldserve :shrug:

runtime revelation - which do YOU think is better?

dhabell

Newly Enlightened

Black Rose

Flashlight Enthusiast

Black Rose

Flashlight Enthusiast

The Dane

Enlightened

dhabell

Newly Enlightened

45/70

Flashlight Enthusiast

The Dane

Enlightened

45/70

Flashlight Enthusiast

Magic Matt

Enlightened

paulr

Flashaholic

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