I would like to share some findings on the energy consumption of different microSD cards, inspired by earlier posts by Javier Seoane and Laura Molles (https://www.openacousticdevices.info/group/support-forum/discussion/923f8974-c6a1-4283-a89c-8d9c71b877af).

Since SD‑card write current is one of the main contributors to AudioMoth power consumption, choosing an efficient card can substantially extend deployment time.

Motivated by a limited budget and the rising prices of memory cards, I recently decided to acquire and test several lower‑cost, slower cards. I used a power meter capable of measuring true‑RMS voltage and current and integrating them into mAh. All measurements were performed on AudioMoths running firmware 1.11.1, using default settings (55 s recording, 5 s sleep) at 48 kHz.

All cards were purchased in 2026. I found no variation between samples of the same model.

I deployed the cards in the field and compared the voltage reported in the metadata with the discharge curve of the AA alkaline batteries used. The results matched the lab measurements well. I was also able to fill the 64 GB cards with low consumption (9.0–9.6 mA) while running on Ni‑MH rechargeable batteries. Field temperatures were mild (5–15 °C / 40–60 °F), which helped battery performance.

My main conclusion are:

• Kingston Canvas Select Plus cards remain excellent in terms of energy consumption.

• PNY Elite / Pro Elite cards perform just as well as the Kingston models.

• The most energy‑efficient cards can be used with Ni‑MH rechargeable batteries.

• ADATA High Endurance, Intenso, and SanDisk Extreme cards are still usable with alkaline AA batteries, but less efficient.

• It’s worth measuring the energy consumption of each card before first deployment, as differences between brands are substantial.

  
  

With the OpenAcousticDevices team never sleeping, I’ll likely repeat these tests with firmware 1.12.1.