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EEVblog #751 - How To Debunk A Product (The Batteriser)
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MrAl:

--- Quote from: Wytnucls on June 07, 2015, 10:49:30 am ---The curve published by Duracell for 100mW is much flatter and goes below 0.8V.
At 1V, the load will draw 100mA and 170mA at the claimed 0.6V threshold, to maintain that power.
10 to 20% battery life extension seems plausible at that power level.



--- End quote ---

Hello,

I used a similar curve to calculate an approximate 100 percent gain at a cutoff of 1.3 volts.  We KNOW that a boost circuit can do this, but the real problem is we dont know ALL the specs of this thing yet, like can it do a 1 amp load for example?
For most real life applications a boost circuit is designed AROUND a given application.  It's not designed for just ANY ol' application because it has to be optimized for that application, and that means the choice of parts like MOSFET, inductor, etc.  There's no choice allowed here as the circuit you buy would be the same one i buy, and we might have entirely different products to use it in which draw significantly different currents.
mikerj:

--- Quote from: Wytnucls on June 07, 2015, 10:49:30 am ---The curve published by Duracell
--- End quote ---

The chart I posted was straight out of the standard Duracell MN1500 datasheet..  The "Plus Power" and "Ultra power" variants all look very similar, though Duracell have cunningly changed the power values so they can't be directly compared.
AndyC_772:

--- Quote from: mikeselectricstuff on June 07, 2015, 07:17:05 am ---Based on common devices, likely to be somewhere between 5-20uA, but this will be drawn at the output voltage, so scale this by the step-up ratio & efficiency

--- End quote ---
That's better than I expected. Some combination of pulse skipping and a decent sized output cap to reduce the ripple voltage, presumably...?
mikeselectricstuff:

--- Quote from: AndyC_772 on June 07, 2015, 12:14:58 pm ---
--- Quote from: mikeselectricstuff on June 07, 2015, 07:17:05 am ---Based on common devices, likely to be somewhere between 5-20uA, but this will be drawn at the output voltage, so scale this by the step-up ratio & efficiency

--- End quote ---
That's better than I expected. Some combination of pulse skipping and a decent sized output cap to reduce the ripple voltage, presumably...?

--- End quote ---
Yes - they generally have a pulse-skip mode. The big catch is that the front-page quiescent current spec is from the output, which can be a significant issue if boosting to a significantly higher voltage like 5V
mrkev:
As someone who worked in shop with electronics, I came across only few products that couldn't be powered from rechargeable batteries.
I would say that it was probably more common few years back, when they didn't have devices that could run on that low voltage (like OA in some walk-men type device) but it's pretty much only case of cheap electronics now...
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