Help making a diy power bank

[DeagleMaster]

I have 17 different 18650 batteries. Can I use them all to make a diy power bank or do they need to be the same?

[Dujith]

You can use different brands. Voltage will be the same. mAh however wont.

Just get a good voltage regulator and read up before you start. There are LOADS of guides around. Its not hard but ist also easy to do it wrong and blow up your devices  

[DeagleMaster]

5 minutes ago, Dujith said:

You can use different brands. Voltage will be the same. mAh however wont.

Just get a good voltage regulator and read up before you start. There are LOADS of guides around. Its not hard but ist also easy to do it wrong and blow up your devices  

So as long as the voltage is the same, difference in mAH won't matter?

 

[Dujith]

You can put them together yes. It will however matter for the effective mAh you are going to get out of them.

Depending on serial or parallel configuration.

ie. putting 2 in series will double the voltage BUT the lowest mAh will decide how long it can keep up.

in parallel its the capacity added together .

 

This is a simple representation of how it works, but its close enough.