Having two 3.7V "3000mAh" Rechargeable Li-ion batteries, I tested connecting them in series and parallel.
Using a multimeter, I measured the amperage of single batteries and it's about 6A. When connecting them in series, the voltage is doubled (it becomes 7.4V).
When connecting them in parallel, I expected that the amperage will be doubled, but it's not. It remains 6A.
Why does this happen? How can I increase the amperage using more batteries?
From what I know, when connecting batteries in series makes the voltage to be increased and when they are connected in parallel, the amperage is increased–but in my tests this last expectation didn't happen. Why?
This is how my circuit looks like:
My two batteries, in parallel, connected to ampermeter.
Best Answer
As the comment mentions, paralleling and short circuiting lithium batteries is potentially very dangerous if you don't know exactly what you are doing. Most Li-Ion batteries have a protection circuit which includes overvoltage and overcurrent protection, but it's still not a good idea at all. Much better would be to test this using a couple of small alkaline batteries (e.g. AAA) and still do it briefly.
If you absolutely must test the current on the Li-ions, then read the datasheet, see what the maximum current rating is and for how long, then use external current limiting on each battery.