First of all I know Voltage goes Up in Series and Capacity/Total Current in Parallel.
But I have confusions,
For example let’s say we have 2 Li-ion cells,
Both 3.7 volts and 2000 mAh or say 2 AH.
When their volts go up to 7.4 volts why doesn’t it go to 4000 mAh as well?
Where does the other 2000 mAh go?
I know because Battery is now delivering current at faster pressure (volts) but it still doesn’t explain why battery is not called 4000 mAh after It’s put in series.
-x-x-x-
In: Physics
Most batteries are 1.5V
We have 0V at the negative end and 1.5V at the positive end.
If we put two in parallel, we have two 1.5V regions connected with a 0Ω wire and two 0V regions connected with a 0Ω wire. That’s fine, it just means we have a battery with twice the capacity (more mAh) and each battery is supplying half the current the circuit needs at 1.5V.
Let’s assume it is a 15kΩ circuit, that means if we apply Ohm’s law, R=V/I, the circuit will draw .1mA from the batteries, or .05mA from each battery
If each battery has 10mAh of charge, then a single battery can power the circuit for 100 hours, or two batteries in parallel can power it for 200 hours.
If we instead put the batteries in series, we have on battery at 1.5V that’s now putting the “floor” for the other battery (which was 0V) up to 1.5V, and the positive terminal is still 1.5V above that, to we have 3V at the positive end, 1.5V in the middle, and 0V at the negative end. It’s like we have one big battery with twice the voltage.
Let’s put it in the same circuit. Since it’d 3V on a 15kΩ circuit, it’s now drawing .2mA of current. Since each battery still has 10mAh, and we have 2 of them, that’s 20mAh, so we can only power the circuit for 100 hours
Latest Answers