Well I think that’s what I need. I’m very new to this hobby and I have several ideas, and I’ve come to find out more os them need 10 watts of power in a very narrow space.
So I bought a few of these: Polymer Lithium Ion Battery - 110mAh. Each cells outputs a nominal 3.7V at 110mAh. So far they seem really nice.
But how do I get the watts I need from them?
I understand ( a bit about ) serial and parallel connections, so I thought I could run 3 of them in series.
Would that do the trick, and more importantly, how could I recharge them?
Thanks so much for your help. As a new electronics hobbyist, I really appreciate it.
You better explain more about what device you are trying to power. Just saying it needs 10 watts means nothing. You cannot just stack (lipo) batteries together and hope that the device works. The voltages add up in series and that might kill your device. Also, is that 10 watts meant to be peak power, or average power flow? Aside from that you need protection circuitry on them to prevent undervoltage and overvoltage from killing them.
Ballpark calculations can be made with:
power=voltage*current
and
battery capacity=average current * duration * battery efficiency
If you are drawing 10 watts out of 3 lipo-batteries of 110mAh in series then expect less than 7 minutes of duration. I don’t know what the efficiency is that you can expect from lipos, so I’ll just state it is less than the value calculated. Others may correct me with more believable numbers. It depends a lot on the actual current you are trying to draw from them.
Average current= 10 Watts/ 3.7 nominal voltage / 3 batteries in series= 900 mA
Duration < 110mAh / 900 mA < 0.122 hours ( or < 7.3 minutes)
