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iam4722202468 / ThinkpadBattery

Open source Thinkpad T420 battery design
MIT License
258 stars 23 forks source link

The laptop part of the circuit #16

Open exander77 opened 9 months ago

exander77 commented 9 months ago

Hello, I would like to use ThinkPad battery to charge feed power to Raspberry Pi and ability to charge the battery, can you offer any support with this? Or point me in the right direction?

Bromiun commented 9 months ago

No need for thinkpad battery. Just buy two 18650 lithium ion batteries. Connect them serially and that is about 8.4 volts. Use this to power the Rasberry pie.

To charge, get a 9 V DC power supply. Put one 1 amp diode in series with positive terminal. Measure voltage. It should be 8.4 volts. Put a 1 ohm resistor in series with the diode. This is now your charger for the two batteries in series.

Each diode drops the voltage by 0.6 V. If the power supply is higher than 9 volts, put several diodes in series so it drops down to 8.4 volts.

If you want longer battery life, get two more 18650, and connect each in parallel with the two that are in series.