Advice needed — Battery specs & microcontroller - Page 1
Forum section: electronics / projects

author: Saoirse
author_rank: Newbie
timestamp: September 18, 2025, 02:49:14 am
content: Hi all,I’m designing a hybrid buoy (solar + wave energy harvesting) for real-time water quality monitoring in fishponds with the goal of early detection of harmful algal blooms (HABs). The buoy will host several sensors and a small embedded system that logs data and sends alerts to farmers or a cloud dashboard.Before finalizing the power architecture and control electronics, I need community input on battery specifications (chemistry, nominal voltage, Ah, recommended DOD, BMS, charge/discharge rates, temp ratings) and which microcontroller (MCU) family or module you’d recommend for this use-case (and why). Below I’ve summarized the project context, assumptions, and sample sizing so you can see where my questions come from.Project context / constraintsSensors: temperature, pH, dissolved oxygen (DO), turbidity, chlorophyll-a (fluorometer). Some sensors wake for the reading and sleep between samples; some are always-on (e.g., multi-parameter sondes).Communications: could be LoRa (to nearby gateway), or cellular (NB-IoT/LTE) depending on site; comms choice strongly affects power draw.Power sources: PV (solar panels) + a small wave energy harvester. Both feed a charge controller that charges the battery pack.Deployment: fishponds/coastal; remote/off-grid; expect high humidity, salt exposure, tropical heat.Target uptime: continuous monitoring; design for 3 days autonomy without recharge as a conservative baseline (user wants reliability during extended cloudy/low-wave periods).

author: Ammar
author_rank: Regular Contributor
timestamp: September 18, 2025, 01:45:44 pm
content: Texas Instrument have a range of energy harvesting low power microcontrollers you could use. But more information is needed.In terms of power consumption though, the actual transmission of the data to the "cloud dashboard" is going to consume the most power most likely. Orders of magnitude more than your sensors perhaps.You need to provide more detail to get better advice. In particular:- datasheets for all the sensors you plan to use- frequency of updates to the "cloud dashboard" e.g. every second, minute, hour- transmission range required- size and dimensions of the bouy- max mass the buoy can take

author: BadeBhaiya
author_rank: Regular Contributor
timestamp: September 19, 2025, 07:28:05 pm
content: As the poster above stated, more information is requiredAlthough I will still recommend you to drop wave energy harvesting. You will need moving parts for it afaik, which are just more likely to break. Plus you don't even get much energy out of the whole ordeal, and worst of all its not predictable. Again, I may be wrong here, but I have been burned by energy harvesting a few times. Solar is the absolute best way to go.

author: mariush
author_rank: Super Contributor
timestamp: September 19, 2025, 07:45:42 pm
content: It would probably be cheaper to combine a rechargeable battery + solar with a high capacity non rechargeable battery , for example a 3.6v 19Ah Lithium Thionyl Chloride battery :https://www.digikey.com/en/products/detail/tadiran-batteries/TL-5930-S/512523- it would run for 1 year or more at a few mA power draw , so you could measure and cache readings and transmit only when power is available or maybe once an hour if no rechargeable energy is available.I was thinking of taking advantage of temperature differentials (ex have a few meters of wire to have colder water at the bottom and warm at the top ) but most likely you won't harvest that much.