There is an obvious compromise to be made between battery size and battery capacity, and so we decided to consider two configurations:

  • for usage cases where size is not a concern, e.g. when the board is used for fixed environmental sensing, a large, high-capacity battery is best; and
  • for situations where size is important (mounted on a performer’s body or a handheld instrument, for example) and the battery should be as small as possible.

For logistical and ecological reasons, the battery should be rechargeable and last at least as long as one rehearsal, i.e. approximately 5 to 6 hours. Our board draws about 70 mA of current, when used with a regular XBee, transmitting data every 50 ms, without activating a sleep mode. Depending on what sensors you have attached, you may consume more current.

The batteries we have tested include:

Li-Ion Poly 500 mAh

Lithium Ion Polymer Battery - 3.7v 500mAh from Floris.cc

Battery is about as large as, though a bit wider than the board, very flat.

Li-Poly Sparkfun 400mAh

Polymer Lithium Ion Batteries – 400mAh; Sparkfun no: PRT-13851

Battery is about as large as the board, very flat.

Li-Poly Sparkfun 860mAh

Polymer Lithium Ion Batteries – 860mAh; Sparkfun no: PRT-00341

  • measurements made with revision A of the MiniBee in 2010

Long battery life (almost 10 hours).

Recharge time ca. 2.5 hours (Using the LiPoly Fast Charger; SparkFun no: PRT-08293).

Battery is slightly larger than the board, very flat.

Li-Ion coin cell Sparkfun 200mAh

Coin Cell Battery Rechargeable – 24.5mm; Sparkfun no: PRT-08818
together with Protection circuit Module (PCB) for 3.6V(3.7V) Li-ion (18650/18500) cell Battery

  • measurements made with revision A of the MiniBee in 2010

Short battery life (almost 2 hours).

Recharge time ca. 30 minutes using the LiPoly Fast Charger; SparkFun no: PRT-08293.

This coin cell fits within the footprint of the PCB so a battery clip has been added from revision B of the board.

AA-sized Li-Ion 900 mAh

Protected UltraFire 14500 AA sized 3.6V Li-Ion Rechargeable Battery 900 mAh CR14500

  • measurements made with revision A of the MiniBee in 2010

Long battery life (almost 10 hours).

Recharge time ca 3 hours (with Ultrafire WF-138 3.6 volt Lithium-Ion AA / AAA battery charger).

Usable with a standard AA-battery holder.

Towards the end of the battery life, the battery turns off at intervals of about 10 seconds and turns on again, rather than just turn off completely.

18650 Li-Ion 2400 mAh

Protected UltraFire 18650 3.6V Li-Ion rechargeable Battery 2400 mAh

  • measurements made with revision A of the MiniBee in 2010

Very long battery life (ca. 24 hours).

Recharge time ca. 12 hours.

Large battery, but useful for installations where size is not a constraint and recharging is part of the design, e.g. solar powered recharging.

AAA-sized Li-Ion 500 mAh

UltraFire 10440 AAA Li-Ion 3.6V Rechargeable Battery 500 mAh CR10440
together with Protection circuit Module (PCB) for 3.6V(3.7V) Li-ion (18650/18500) cell Battery

Unfortunately, we found that a majority of these batteries would not recharge after using them only a few times.

Our advice: don’t use batteries that don’t come with their own protection circuit built-in.

page created on: last changed on:
28 March 2018 28 March 2018