La Parguera CREWS station offline

I'm sorry to report that the CREWS station in La Parguera is offline again.  It seems to have been suffering a very slow power drain ever since our last visit in January (see attached chart, which shows data from Dec 1st through this past weekend, with 2013 days-of-the-year as the X-axis -- the blue lines drop to zero twice during the week we were visiting and cutting power temporarily to the station).

Click this image to see a larger version.

Possible causes?  It could be as simple as a loose connection in the brain wiring up top, or that the connector for the solar panels is loose.  In fact I would guess that that's the most probable cause.  Other possible causes, off the top of my head, could include a bad charger-controller, bad solar panels, or bad batteries.  But I would say it's almost impossible that there could be anything wrong with the batteries, and rather unlikely that the solar panels themselves could be at fault.

Unlike the other times this station has lost power, it is extremely unlikely that any of the underwater instruments have flooded.  That kind of short-circuit has very quick and dramatic effects, taking the station from 100% normal to completely offline in a matter of hours.  This problem, whatever it is, has been going on for months.

The solution?  There is nothing that can be done to diagnose/fix this problem that does not involve climbing and opening the pylon.  This means that someone from AOML (probably me) will need to visit.  It might be a kind of tricky problem to resolve since it may take hours or days following any attempted fix to know whether the fix was effective.

In the meantime, I must assume that the station will continue its slow power decline.  It seems like the transmitter no longer has enough power to transmit, but the datalogger can be expected to continue running (and logging data locally) for a while longer.  My guess is that if the present rate of power decline continues, the station could continue logging data locally for another two months.  [I would not expect the problem to resolve itself spontaneously, although it's possible it could.]

We will have to weigh our priorities and schedules here at AOML to determine how soon a fix can be attempted.

station cleaning

[From an email from Diana Beltran, March 11, 2013 4:06 EDT]

The last tuesday March 5/13, I made sensors cleaning station. We started at 8:30 am, the sensors were all covered with filamentous algae and some white calcareous algae. The chains and the central column were partially covered with Bivalves, sponges, filamentous algae, some corals, etc.