Power usage of Mayfly1.1 with Hydros 21 cTD and LTE BEE cell modem

Your questions are all very subjective to a variety of operating conditions, so I can only give you some broad estimates of what we’ve experienced with the 300+ stations we’ve installed and maintained.

We typically put a 4400mah Lipo battery on the Mayfly boards because on standard logger configuration, they can be charged fully by a 3.5w or 5w panel in just a few hours of direct sun.  It gets more complicated if you’re a shady location or a higher latitude, or by time of year.

The overall power draw of a CTD-only station with LTE cellular module will mostly be the affected by the time it take the cellular module to connect to the network and send the data.  The CTD uses only a few milliamps of power for a couple seconds, and the Mayfly board sleeps when not taking a sample, so if you’re taking readings every 5 minutes, you could operate for several months without a solar panel if you weren’t transmitting via LTE.  At 15 minute intervals, I would guess you could get 3 or 4 months of lifespan, especially if you upgraded to a 6600ma battery.  With the new EnviroDIY LTE cellular module, we typically get at least 3-4 weeks of operation without a solar panel at 5 minute sample rates before the battery starts to get low.  However, cellular signal strength and network availability at the monitoring location determines how long the cell transmitted is on during each transmission.  I’ve seen some stations make their report in 5 seconds or less.  Other will stay on nearly a minute each time before completing the transmission.  (The old Digi brand LTE boards used 4 times more power during operation and took close to a minute for each transmission, so those boards really killed our battery life. We’ve since replaced them all with our own sim7080 EnviroDIY LTEbee which are much more efficient.)

So stations with long transmission times and shady locations will struggle with battery life sometimes, whereas stations in strong signal areas and sun will last almost indefinitely.  We have some stations that were installed in 2016 that are still using the original Lipo battery pack.  The lifespan of the Lipo pack seems to depend more on temperature extremes and moisture.  The blue 4400mah packs we like to use (because they have the compatible JST-connector polarity) have open ends that allow moisture to get into the insides of the pack and cause corrosion/rust on the metal tabs that connect the two cells.  When one of those tabs rusts through, the pack becomes unstable and soon dies.  We’ve had packs last many years in dry conditions, but if a logger enclosure leaks or has high humidity inside that results in frequent condensation on the battery pack (usually at night when temps drop) then those packs will only last a year or two. Keeping a desiccant pack in the logger enclosure and making sure there are no leaks will greatly extend the life of the battery.

The default charge rate of the Mayfly v1.1revB is 500 mA.  The 5w ETFE panel from Voltaic Systems can generate about 900ma in full sun, but unless you change the default charge rate, the Mayfly will be limited to 500ma of input current.  You can adjust this by changing solder jumper SJ15 (and SJ14) as explained on the Mayfly Jumper Settings page, however see the note on that page that says using a charge rate above 500ma will result in very high temperatures of the charging ic chip on the Mayfly, which could damage or shorten its lifespan.

@rogers1313  gosh its all depends on the software you are using – what’s the version of software and the source. Since its open source software and hardware, and you can look at the software – its possible to guestimate those answers. Then since its software that causes the most power usage, it needs testing.

For a turnkey system, assembled off the shelf, those are reasonable questions to ask (and have tech support pay for).

For the solar  being unavailable due to a storm – I use a target  figure of two weeks.

I’m a fan of ModularSensors software and also a critic, with ways of solving the problems. I believe i’m one of the few people to publish the power usage I’ve got..

The Mayfly 1.1 is better at battery voltage measurement than the 0.5, but read some of my blogs on measuring battery voltage.

The standard release  transmission software doesn’t have reliable message delivery built in, and the standard software is also IHMO really really really bad at managing power.

The simplest way of answering your question – build the system you want, delivering readings to MMW, put in a voltage measurement off the battery, and then let it run for 1week or 2 weeks and see how the voltage drops on the battery. If possible share the results here as well.

From my measurements, the biggest user of power is posting to MMW. MMW in my experience has a wide range of of how long it will take to respond, including no response.   I default to a timeout of about 20seconds for a no response, but it can respond with successful POST ‘201’ in as little as 0.4Secs.

I have shared  multiple postings of my power usage measurements, and what I’ve done to make the power usage more efficient – and in the end it depends on your application and how reliable you need it to be –

Just my 2cents.

We’ve published some sample power usage readings over the years, but it varies by station configuration and board version and a few other settings.  But in general, a Mayfly v1.1 revB board with an EnviroDIY sim7080 LTEbee will use about 8 mA at idle, 0.650 mA in sleep mode, and a max of 110 mA for a few seconds when actively transmitting.  But your most accurate numbers are going to come from doing your own power measurements after you’ve programmed a board to work with whatever hardware you’ve selected.

We’ve published some sample power usage readings over the years, but it varies by station configuration and board version and a few other settings.  But in general, a Mayfly v1.1 revB board with an EnviroDIY sim7080 LTEbee will use about 8 mA at idle, 0.650 mA in sleep mode, and a max of 110 mA for a few seconds when actively transmitting.  But your most accurate numbers are going to come from doing your own power measurements after you’ve programmed a board to work with whatever hardware you’ve selected.

Some recent posts here explain the current difficult environment for calculating power usage on the mayfly as its dependent on a fast response from the server.

https://github.com/ODM2/ODM2DataSharingPortal/issues/649#issuecomment-1561690674

My implementation is to ensure that there is sufficient reservoir of power in the battery for taking sensor readings, and when the battery power is “low” (3.8V) not to use it for Modem Communications. My reliable delivery algorithm POSTs the reading to MMW,  and if it gets a bad (not a  201)  then stores it to a queue on the uSD. Only if it gets a good 201 ACK from the server, it then attempts to POST all the historical queued readings.

On experiencing a recent virtual month long outage on the MonitorMyWatershed the voltage response on the battery can be seen here

https://monitormywatershed.org/tsv/TUCA_PO03/4805/

as it attempts to push the historical queued data to MMW  however the biggest user of power is the 504 timeouts of ten seconds while waiting for a non response from MMW.