Battery Replacement for small project

[pblanos]

Hi I have connected a https://www.sparkfun.com/products/10999 with a **broken link removed** for a small project

The circuit that has been created is shown in the following link:

**broken link removed**

My question is that I would like to replace the 9V battery with the following 3.7 V rechargeable LiPo one and I don’t know how. Are the characteristics of this battery suitable for my project? The reason I am changing the battery is to minimize the circuit to a portable device.

https://www.farnell.com/datasheets/1666646.pdf

Can you help me please? Thank you in advance

 

[ZASto]

If you connect those two boards to the 9V battery you will fry them.
You can connect these boards directly to the LiPo

 

[pblanos]

It is actually working perfectly the way it is connected now, I just want to replace the 9V battery with a 3.7 rechargeable LiPo one.

 

[godfreyl]

The Pro Micro and Bluetooth Shield are both designed for 3.3V and won't be happy connected directly to a 9V battery. Is there some other circuitry involved - perhaps a voltage regulator to drop the 9V down to 3.3V?

The circuit that has been created is shown in the following link:

**broken link removed**

All I see there is a couple of photos of the Pro Micro and Bluetooth Shield. Maybe that's the wrong link?

 

[Audioguru]

It has a diode feeding a 3.3V regulator. I did not look up the dropout voltage of the regulator and I did not lookup if the processor works from a 3.2V to 4.2V Li-Po battery voltage.

 

[Golden Electronics]

If possible use Super capacitor reduce size & but increase cost

 

[Audioguru]

If possible use Super capacitor reduce size & but increase cost

No. A capacitor is not a battery.
A battery voltage stays close to a high voltage for most of the time of a discharge. Then when it is almost dead its voltage drops quickly.
A capacitor voltage IMMEDIATELY begins to drop quickly.
The graph is in Google Images.

 

[Golden Electronics]

I suggest not regular Capacitor. Search on google for Super Capacitor of Panasonic which can be use as Battery

 

[godfreyl]

It doesn't matter. Supercapacitors store less energy than LiPo batteries, for the same weight or size. They can deliver greater power than batteries of the same size or weight, but that's not what's needed here.

 

[Audioguru]

Golden Electronics,
I guess you did not look at the graphs in Google. Here is one of them:

 

[pblanos]

How can I measure the Vin (min) that my circuit requires in order to see if 3.7V source is capable of supplying sufficient voltage amount?

 

[Audioguru]

How can I measure the Vin (min) that my circuit requires in order to see if 3.7V source is capable of supplying sufficient voltage amount?

1) Lookup the maximum dropout voltage of the 3.3V regulator.
2) Lookup the minimum supply voltage for the processor.
3) Lookup the minimum allowed voltage of the battery or its low voltage cutoff from its protection circuit (if it has one).
4) Add the maximum forward voltage drop of the diode.
Note that if you allow a Li-Po battery cell to discharge to less than about 3.2V then it will be damaged.