# [Solved]Li-Ion Batteries

Hi,
What I am asking is not a problem but just a question that Google didn't answer. I am new to li-ion batteries (and to applications of current also). I saw in many Youtube videos that just two 3.7V 18650 batteries (of, sometimes, 2600mAh) powering an Arduino Uno, a Motor Driver(to me, L298N), some sort of sensor (let us say Bluetooth module) and 4 DC BO Motors running at a good speed. So my question is how just 7.2V(3.7V + 3.7V) can power all this?

Thanks
Kalpit

The ability of the batteries, wired in series, to supply the current.

Have a go at looking up what mAh means, try: https://www.quora.com/What-does-mAh-say-3-000-mAh-mean-in-a-battery or do you own internet search on the letters "mAh".

Do You Mean That A 12V 1Amp Motor Can Run If It Is Given 1V 12Amps?

Kalpit

No.

7.2V can power any amount of 7.2V loads, so long as the source can provide enough current.

For example all the mains applicances in a building run off the same 110V or 240V.

Each load requires a particular voltage - provide that voltage with enough current and the load is happy.

One reservoir can provide water to a million water taps if the pipes are wide enough.

Does That Mean That A Power Source With 7.2V Rated At 1Amp Supply Power To Ten 7.2V Things Rated At 100 mA?

If Yes, Two Motors Of 6V 10mA Joined Together Will Result A Thing Taking 12V 10mA Or 6V 20mA?

Kalpit

You don't add voltages like that.

Think about your house. What is the mains voltage where you live? 120V, 240V? Let's say its 240V

How many lights are in your house? 20? If you added their voltages together, the house would need 4,800V if all the lights were on together. But the supply to the house is only 240V, and all the lights work, so your idea can't be correct.

When devices share the same power supply, they are connected in parallel, not in series. They each get the same voltage, but different current will flow through each device according to its needs.

You need to understand the concepts of voltage and current and connecting components in series and in parallel.

Thanks For Clearing The Concept.

Kalpit

Kalpit,

If you want to know more then you need to learn about Ohm's Law and Kirchhoff's circuit laws, both ar fundamental to all electrical circuits.

PerryBebbington:
Kalpit,

If you want to know more then you need to learn about Ohm's Law and Kirchhoff's circuit laws, both ar fundamental to all electrical circuits.

Thanks, a lot.

Kalpit