Energy consumption of SD cards
I would like to share some results as a continuation of an earlier post on energy consumption of SD cards at https://www.openacousticdevices.info/support/sd-card-support/u1-vs-u3-microsd-cards-field-data-contradicts-recommendations?origin=notification
We conduct an indoor experiment using Audiomoths with firmware version 1.11.0 in a recording window of 180 minutes. The sample rate is set at 48kHz, and the gain is set at medium. We enable sleep/record cyclic recording. We use daily folders for the generated WAV files. We combined two sets of different recordings and sleep durations with different SD cards and battery models to assess the effect of sleep durations, and the type of card and battery. These are:
Alcaline vs lithium
Lithium batteries do not extend the operating time beyond what alkaline batteries did when the recording schedule was intensive (recording each minute during the 180-minute window). Compare BAU2 vs BAU1.
Recording scheme
As it was expected, a less intensive recording scheme (recording one out of five minutes during the 180-minute window) allowed recorders to operate longer, with both type of batteries. Compare BAU1 vs BAU1_deg and BAU2 vs BAU2_deg.
SD card
Our slow card allowed recorders to operate longer than the fast cards did for both recording schemes: compare BAU2 vs BAU1_b (5’’ sleep, 55’’ recording), BAU1_deg vs BAU1deg_b (240’’ sleep, 60’’ recording).
As it happens, all the cards we tried were manufactured in Taiwan.
And maybe that is the crucial point.
Manufacturer
In another extensive deployment with audiomoths equipped with SanDisk Extreme 64GB cards and Duracell Pro alkaline batteries spread in around 100 outdoor sites in mainland Spain (recording window 150 minutes from 30 minutes before sunset, sample rate 48kHz, two-minute sleep and one-minute recording) we found the manufacturer country to have a consistent effect in the durability: those cards made in Malaysia and China were still operating after five months (these were manually stopped), while those from Taiwan interrupted operation in roughly half of that time (see graph below).
Hi again everyone - FYI I've run a little test with a few different cards with a multimeter in series as Alex suggested. I used a Dev 1.0.1 with Powerex 2700mAh batteries, recording frequency 48kHz. I've just noted the range of current values during a 1min test for each:
I estimate my average values for the two older SanDiskExtreme cards are totally in alignment with the previously posted SD Card guide, and my value ranges for the SanDiskExtreme and Samsung cards align with how these cards have performed in the field. I haven't tested the three newer, low-speed "trial" cards in the field but will do that in the next couple of weeks. Below are images of the cards, front and back. My SanDisk cards were all made in China; Samsung cards was made in the Philippines. The three newer cards were all made in Taiwan.
The difference beween my old and new SanDiskExtreme cards is really striking, and all 15 of the new ones are very power-hungry.
As a side note: I will definitely not be buying Samsung Pro cards again regardless of the energy consumption issue. About 10% of the cards I purchased failed completely (i.e. became totally unreadable) after less than a year of use.
Cheers,
Laura