Alkaline Battery Pack
How to set up a power supply with 2 different currents?
Suppose I have an electronic device that requires 2 different currents through 3 different circuits. One is a 12V 0.8A, the other 2 are 3.3V 2.7A.
I want to power this with a single battery pack made of multiple D Cell Alkaline Batteries.
How would you design the Power supply?
The nominal output voltage of single-use D cells is 1.5 volts. I assume the loads need not have a common ground. The current capacity is about 7.8 ampere-hr, so you need to try to equalize the current drawn from the individual batteries.
So, you need 8 of them in series for the 12 volt supply. The string can then be tapped across three of the batteries for one supply, and three other batteries for the other supply, with a 0.22 ohm resistor common to the return paths of the two supplies, connected to the middle of the four batteries, to reduce each voltage to 3.3 volts.
Later: Hi,
My first idea was wrong.
The easiest way to explain how to do it right is to move circuit two and its associated resistor In your schematic one battery to the right. Then, circuit one and two are not connected to one another. Then, replace both 0.22 ohm resistors with 0.44 ohm resistors. That should be okay.
Energy-saver bulbs may be recycled in St. Peters
The energy-saving compact fluorescent light (CFL) bulbs now may be recycled at St. Peters' Recycle City.
 |
 40 PACK OSEL ALKALINE BATTERY AAA LR03 AM 4 15V  US $.95 |  50 Rayovac AA Alkaline Batteries Wholesale Bulk Lot Pack 4 Extra FREE US $17.99 |  Duracell Coppertop AAA 15V Alkaline Batteries 16 Pack US $12.00 |
 Duracell Ultra AAAA 2 Pack Alkaline Batteries US $.99 |  Alkaline Batteries by Rayovac Ultra Pro Choose D C 9V AAA AA Various Packs US $18.99 |  AA Duracell Alkaline Batteries 288 Pack US $98.00 |
| Powered by phpBay Pro |
 | Dynex High-Capacity AAA Alkaline Batteries (8-Pack) Sale Price: $4.13  |
 | Streamlight Nano Light Miniature Keychain LED Flashlight |
DescriptionTruly tiny, the Nanolight is a weatherproof, personal flashlight featuring a 100,000 hour life LED. Includes a non-rotating snap hook for easy one handed operation when attached to a keychain. |
 | Streamlight 61052 Septor LED Headlamp with Strap List Price: |
DescriptionWith seven, ultra-bright, white LEDs, the Streamlight Septor LED Headlamp features three levels of lighting for a wide range of applications including up-close detail work and long-range viewing. Adjustable straps help secure the light to any head size, and a 90-degree tilt mechanism allows you to point the light exactly where you need it... |
 | Streamlight Stylus 3-AAAA LED Pen Light List Price: |
DescriptionStreamlight Stylus: Sleek, ultra - bright lighting you can slip in your pocket... SAVE! Small size, big power! The Streamlight Stylus is so bright you'll swear you're carrying a full-size flashlight in your pocket! That's because the advanced reflector optics and single powerful LED deliver up to 400% more lighting range than traditional penlights... |
 | 23AE 12 Volt Alkaline Battery List Price: |
Description23A 12 Volt Alkaline Battery |
 | Lenmar Adapter, D Size Shell, for any AA Battery List Price: |
DescriptionLenmar AA+D Size Nickel Metal Hydride Battery PRO-AA2D Batteries |
 | Microsoft Wireless Optical Desktop 1000 (PC & Mac) List Price: |
DescriptionOptical - Mouse - USB Receiver |
How to Turn an Old UPS into an Alkaline Battery Charger!