How to multi task :
Filling the pool;
Scrapping the shit up;
Getting vitamine D and fresh air;

Ever saw a Power bank?
Btw it's a lot cheaper to buy a good powerbank (6A up) and brake it up for good price that buying the batteries.
RIP Chinese power back, Hello batteries...
Or USB charger, depending on what got burn

I made my own powerbank from 2 "dead" laptop bateries. In total that mostrosity has 12 cells, 24Ah in total(at 4,2V). (2200mAh per cell) if im not mistaken. It can output 4,2*6 V It has ebay BMU that "can" charge it but i dont trust it.
Thats why i dont use that powerbank now and im waiting for motivation to make the charger (or lab power supply)

Also, have two laptop batteries, but I'm saving them to use as 10V and 11V batteries. the same problem, charging without damage, finding the right charging board and to which pins to connect...

Btw, why does the laptop batteries have so many pins? one per 3.7v battery ?

Btw, my dad bought a 10 euros /8 dollar 12V vacuum cleaner... If it's good enough I'll buy another for my machines...

If ya know what to pick, some items are really worth :p

@GyroGearloose

Laptop batteries usualy contain 6 li ion batteries. The pack contains custom BMU (battery managment unit) and few other components.
Additional pins include connections for temp readout, battery state/wear and others. You have only 2 power pins. BMU takes care of balancing the power. I took them apart because original BMU blocked itself because maximal number of charging cycles was reached. You can reset that but it requires eeprom editing...
I got another BMU from aliexpress.
Thats why taking them apart is a necesity.

@Gregozor2121 Well, If i take it apart I'll just join the bateries to the rest. Already have a few lipo bateries and chargers, plus charging modules to make my custom charger