2 power sources,2 outputs,series or parralel switch

Using Arduino Project Guidance
1

Hello!
I'm planning to build a multipurpose power source.

I wil use 2packs of 18650 batteries and two outputs powered sepparatedly.the packs are 2x4.2v

One of them wil be a programable buck/boost converter- it needs the batteries connected in parralel because of higher voltage. Vin >5v

Second, but the main is a complex device which charge the batteries using micro usb power source. It also have two usb outputs, display for monitoring charging/discharging from usb, and a thermometer.
Vin<=5v

I'm looking for a proper mechanical switch circuit to power two devices sepparated.one using batteries in parralel, and the other using the batteries in series.

rkBXr.png

2

Parallel = still 3.7-4.2
Series = 2x voltage

Can you clarify "2packs of 18650 batteries and two outputs. 2x4.2v"

So, how many cells are you working with here?

3

Do you mean something like this

800×588 43.6 KB

4

I

INTP:
Parallel = still 3.7-4.2
Series = 2x voltage

Can you clarify "2packs of 18650 batteries and two outputs. 2x4.2v"

So, how many cells are you working with here?

I wil have 8 cells.2 groups of 4 cells connected in parralel.

It' exactly what BillHo posted. I wil have two modules connected to batteries.

One module needs all the batteries connected in parralel , that means 3.7-4.2v

The other module needs higher voltage for boosting, so the two groups of 4 cells wil be connected in parralel .7.4 - 8.2v.

Next question

What tipe of switch should i use to switch 3 different contacts at the same time, avoiding short circuit.l?

5

3PDT?