Complex charging formula?

Ideas and questions about MintyBoost kits

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Setharoth
 
Posts: 2
Joined: Sat May 05, 2007 11:49 pm

Complex charging formula?

Post by Setharoth »

First off, thanks for the great kit. Got it together and working with very little issue, hardest part was tweaking the hinges on the Altoids tin so it closed securely :D.

On the FAQ you have a simple formula to calculate extra play time, could you show the complex formula?

Mainly looking for something that takes into account both Battery type ( voltage ), and mAh of the battery.

Ok, found a bit more, maybe I can figure this out ( And dust off those old brain cells, been a few years since high-school electronics ):


<Number of AAs> * <AA Voltage> * <AA mAh> * <Efficency>

Divided by:

<Device Battery Voltage> * <Device Battery mAh>

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »

yes, thats right. dont forget that the efficiency is related to drain and voltage so it can range between 70-90% i usually just say 80% also its not as much device battery voltage as 5V because there is a linear regulator that will turn the 5V into 4.2V to charge the battery (its almost -always- a lithium ion or polymer)

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