Hey guys,
i'm searching for an efficient way of making my 101 project battery powered and as small as possible at the same time. Until now i simply powered it with a 9V battery on the Vin port. What do i have to take into account when i want to power the 101 with a 3.7V Lipo?
I thought about connecting the Lipo to a Lipo charging board first and its output to a 5V Step-up Booster which is directly going into the 5V pin of the 101. But since the 101 is internaly working 3.3V i'm a bit confused if these are the right components? Besides, i have to power a small mobile vibration motor and an external bluetooth modul at the same time (which are now connected to the 5V pin).
Better to remember that a FULLY charged lipo 3.7 starts out quite a bit higher than 3.7 volts ! There is another thread I am going to point you at as it covers the same aspect for a different board
The 3.3v and 5v pins are post-voltage regulator, so you should only use those to power the 101 if you have a reliably regulated voltage of 3.3 or 5v. The VIN pin wants 6-12v, and I've had problems with the 101 rebooting when there's a power draw impulse (like a motor) when the power to VIN is right at 6v.
One solution that works well for me is using the tiny $4 Pololu step-up regulators to take 3AA's to 12v to the VIN pin. That might work for a lipo as well. The 4v-12v conversion is not the most efficient, but projects built that way seem to run a long time for me and can handle moderate loads.
Also if you're looking for small size, have you checked out the DFRobot Curie-Nano? It should behave the same as the 101, but it's smaller and includes a dedicated 3.7v lipo input.
Thank you so much! This helps a lot! In fact i wasn't aware of the DFRobot Curie-Nano, which will fit my current project better than the 101 indeed! Thanks for the explanation and the hint!
lucasainsworth:
The 3.3v and 5v pins are post-voltage regulator, so you should only use those to power the 101 if you have a reliably regulated voltage of 3.3 or 5v. The VIN pin wants 6-12v, and I've had problems with the 101 rebooting when there's a power draw impulse (like a motor) when the power to VIN is right at 6v.
One solution that works well for me is using the tiny $4 Pololu step-up regulators to take 3AA's to 12v to the VIN pin. That might work for a lipo as well. The 4v-12v conversion is not the most efficient, but projects built that way seem to run a long time for me and can handle moderate loads.
Also if you're looking for small size, have you checked out the DFRobot Curie-Nano? It should behave the same as the 101, but it's smaller and includes a dedicated 3.7v lipo input.
Thank you very much for pointing to this, this helps a lot!
Ballscrewbob:
Better to remember that a FULLY charged lipo 3.7 starts out quite a bit higher than 3.7 volts ! There is another thread I am going to point you at as it covers the same aspect for a different board