Minimum supply current Notecard with Notecarrier A

My project is proof-of-concept for a remotely installed device that needs to require little-to-no maintenance. Ideally, I would operate without a battery.

It has a heat recovery-driven generator for the supply power. The full-scale device power will be ample, but for the proof I want to reduce $ cost of equipment and time by minimizing the necessary power.

What is the minimum current necessary to operate the Notecard with Notecarrier A? I don’t expect to need GSM

Hey @tempneff sounds like an interesting POC! Here are a couple of key things to know about the Notecard in terms of power:

  • steady state while idle, the Notecard and Notecarrier draw approximately 8-12 micro amps depending upon input voltage level (from 2.5v - 5.5v)
  • Each sync over LTE takes approximately 8-10 Joules of energy.
  • During delivery of that energy during power-on and transmit, the voltage cannot be allowed to dip below 2.5v, and as a result your design will require sufficient capacitance to buffer the bursts.

You mentioned that you plan to go battery-free, but for some extra detail, we suggest avoiding LiPos as an energy storage buffer due to their limited number of charge cycles and internal drain, and instead recommend using Lithium-Ion Capacitors. If you’re interested, we are working on an LIC storage device and would happy to include you in a beta for evaluation if this is of interest.

@bsatrom thanks for this information, it is helpful. Can you provide me a timescale of the ‘bursts’?

In regard to LIC storage device beta evaluation, count me in!..where do I sign?

@bsatrom are there any other requirements than don’t drop below 2.5v? I am sending around 3.7 volts and sustain 600 mA. When the notecard tries to boot, I see a dip down just under 3V, but well above 2.5…but still no pretty green light.

Are there any power quality requirements? My power source is a thermoelectric generator, but I haven’t included any power electronics yet.

Hey @tempneff there’s more info here but you’ll need to be able to handle a sustained 750mAh draw and brief (in ms) 2A bursts in order to power the modem. Your voltage level is good, but the modem might not be getting enough amperage to power up initially. Your best bet here is to use the generator to power a buffer that can aid in supporting the pulse requirements, either a battery or supercap.

In terms of that LIC beta, I’ll put you on the list and will follow-up when we have more to share!