Help with Peltier TECs, fans and h bridge

Projects General Guidance
1

Hi everyone. I'm starting on a new project, and really need help.
I need to use an Arduino to control the following
-4 X 40mm 2pin fans rated at 12v/0.1a
-3 X 120mm 3pin fans rated at 12v/0.3a
-4 X Peltier TECs model SP1848 27145 with ratings: minimum; 0.9v/0.225a maximum; 4.8v/0.669a.
What I want to do is control the larger fans speed seperate to the Peltier TECs and Small fans.
I think wiring the large fans in series is going to make things easier while reducing the amount of voltage required. From what I understand, if I use a h-bridge, I will be able to control the Peltier TECs.
I want to be able to switch the polarity of the TECs with a momentary push to make button and have an RGB LED indicate polarity of the TECs.
I also would like to provide a low/medium/high/off setting for the TECs using a momentary push button to cycle through the settings (which I think can be done via sending a signal to the h-bridge to control the amount of voltage sent to the TECs.
The small fans are going to be used along with aluminium heat sinks to cool down the TECs and their speed needs to be dependent on the power given to the TECs to cool the hot side down in relevance to the power being use to operate them.
I would like to use LEDs to indicate the power level of the TECs
Like the large fans, I believe wiring the TECs and Small fans in parallel will help to save power and provide even voltage and control over the device.

I would also like to use an LED to indicate the device has been turned on.

I need help to determine what type of h bridge I will need, what type of Arduino is best for this project and how best to wire it.
I have sketched out some ideas about how to wire it and will post it, but they are very incomplete.

I would love to eventually take this off an Arduino and make it a permanent circuit, but that can wait until I get this working first

2

This is what I have sketched up so far, but like I said, it's very incomplete. And because I don't know which Arduino or h-bridge I need, I left it out

IMG_20180418_092339_1024x576.jpg
IMG_20180418_092339_1024x576.jpg1024×576 117 KB

3

A 1k base resistor is ok for a darlington transistor (TIP120 etc.), but not for a common NPN transistor.
A normal BJT needs a base current of 5-10% of the collector current when used as a switch.
In this case 50-100mA, which an Arduino pin can't provide.

So use a TIP120 with 1k base resistor or a logic level mosfet to switch those three fans (~1Amp).
Leo..

4

What exactly are you trying to do with your project?

Use the Peltiers to generate electricity or use them to generate heat and cold?

Do you realise the peltier figures you quote are for electricity generation not temperature?

Your talk about reversing and controlling the voltage makes me think you are going to use them for temperature and if so the amperage you quote is WAAAAY below what you need to run them.

Quick search shows currents of up to 9 amps per unit to generate around 25 degrees difference.

Daz