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Firstly, I want to say thank you for looking at my question. I am trying to make something for my nephew, but I really don't have much experience in electronics, even though I have been researching it heavily.

Basically, I want to make a device in which a slim rechargeable battery (think a phone battery pack) powers all the following:

1) 2 5 Volt Peltiers, (Max 5A, 6.2V @ 19.4 Watts) --> http://amzn.to/2tqHYKM

2) 2 12 Volt Fans with 2 PINS (http://ebay.to/2vwNAo6) OR 2 4 Pin, 5 Volt Fans

3) An off/off switch would be nice, but a power/speed adjuster is not necessary as I want all devices to run on full speed all the time (19.4 Watts); however,an option to shut the device automatically after a certain temperature is reached is necessary.

What I know

I don't want you guys to think I don't know anything, so I know that I need some sort of circuit board that allows me to output and take in either 12V and 5V, or just 5V, and then I need the same circuit board to be able to take a 2, 2 Pin fans (or 2 4 pin fans) and 2 Peltier devices; although I might only need one.

I have been researching and have come across items such as "PWC controller" for a 4 pin fan, yet they have all only been able to take in 12 Volts. I know that circuits exist in which both 12v and 5v power outputs from a 12V power supply .

Furthermore, I know that the board for for power input and output is called a "charging board", but connecting the puzzle pieces in which a rechargeable battery powers what I want is so beyond me.

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    \$\begingroup\$ This will probably not go well here for a whole number of reasons ranging from "where can I buy x" questions being ruled off-topic here, to the less than advantageous thermodynamics. An ipad-sized battery might run your peltiers for an hour; have you considered a re-usable "cold pack" instead? If you want to run the peltiers from a higher voltage you'll need some sort of high current switching regulator, but safely building and especially safely charging a ~12v pack from the types of LIPO pouch cells used in phones is not simple at all. \$\endgroup\$ – Chris Stratton Jul 23 '17 at 1:20
  • \$\begingroup\$ Can you define what is being cooled and how heat is removed? DO you know about thermal transfer mechanisms like THermal mass, heat velocity, efficiency, and thermal resistance? for each layer? What is this for ? \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 23 '17 at 2:12
  • \$\begingroup\$ Hi Tony, thanks. This device is for cooling .2 gallons of water. I have heat-sinks ready with fans attached to the peltiers. The cold side of the peltier will be touching a copper heatsink that will also be touching some aluminium next to a bed of .2 gallons of water. I don't know any of the terms you are talking about, to be blunt. \$\endgroup\$ – Omar Sumadi Jul 23 '17 at 2:57
  • \$\begingroup\$ @ChrisStratton If I made all the electrical components I get 5 volts then, would it be easier to work with? The only problem is that the small fans run 12 volts while the 5-6.2 Volts. Furthermore, 12 volt rechargeable batteries are more expensive which is why I don't want to get them. I have considered a cold pack; however, I wanted something reusable. Lastly, how can I make this project simple then, and what parts should I be looking for other than the ones you mentioned. \$\endgroup\$ – Omar Sumadi Jul 23 '17 at 3:01
  • \$\begingroup\$ They sell re-usable cold packs. Peltiers usually pump less heat per watt than they consume, but let's assume unity. An ipad sized battery stores 42.5 watt hours, which also matches what your peltiers might consume in an hour. Water ice (which is not exactly what's in them, but for argument's sake) has a heat of fusion of 334 Joules/gram. A half kilo of water ice therefore absorbs 167KJ of heat melting, which is about 46 watt hours. Ice pack weights less than the ipad but more than its battery. Costs a lot less, get two and keep one "on charge" in the freezer. Insulate to control rate. \$\endgroup\$ – Chris Stratton Jul 23 '17 at 4:13

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