SediLink radio modem and power use2016-07-22
The next software update will include code for synchronized radio sleep in the SediLink radio modem. This means that remote monitoring in real time can be made with both the SediMeter instrument(s) and the SediLink radio modem in sleep most of the time, thus limiting the power drain. The small built-in solar panel of the SediLink gives enough power to keep this system charged even in low light conditions, if the duty cycle is limited to a reasonable value. In most cases one measurement can be taken per minute without running out of battery.
During the design phase, when deciding the size of the solar panel and the battery capacity the worst case scenario was defined as a high-latitude winter storm lasting for a week, meaning no charging at all for one week. The test shows that the battery capacity is adequate for running the system for one week. It also shows that even a little sunlight every day is enough to gradually charge the battery up again (this was measured indoors to simulate high latitude low light levels).
More than one SediMeter can be hooked up to each SediLink radio modem, but the effect on power has yet to be tested. In many cases it is estimated that up to 3 units can be powered, and this is by design; using 3 SediMeters in the same general spot is a desirable tactic for estimating both the average siltation, and the uncertainty of the estimate.