Weather: Mostly cloudy this morning, but mostly cleared out by noon. Breezy winds and cold temperatures persisted throughout the day. A system is expected to bring rain/snow overnight (1-2 in. possible), tapering off by late morning, but remaining overcast all day. Saturday is expected to be sunny.

Tasking:

  • The morning data check revealed that no data was making it to Boulder since about 1700 CST last night, thus no QC tables or plots were available. Steve fixed the issue around 1030 this morning. Between cockpit and ncharts we did not find any obvious issues with any sensors. 
  • We decided to charge the batteries at lconv using our generator and 2 chargers. We disconnected the solar and measured the voltage on each bank of batteries. The batteries as lconvm showed less charge (around 63% and 12.0 V  according to the charger) than those at lconvt (around 75% and 12.3 V). We charged the lconvm batteries for over 2 hours and couldn't determine if they ever reached a full charge. At about 2.5 hrs the charger showed 100% charge, but the Sunsaver still had the yellow light illuminated. Upon disconnecting and reconnecting the charger is showed significantly less charge and lower voltage than before, which led us to determine that we don't really trust this particular charger. The lconvt batteries did appear to reach sufficient charge to illuminate the green LED on the Sunsaver after about 2 hours. After this we gave up and reconnected the batteries to the solar panels.
  • The sun started to show through the clouds near 1000 CST. After maybe an hour of this direct sunlight we tested the batteries at rel and found that the green LED's on the Sunsavers were illuminated and the batteries showed a charge above 12.8 V. From this we determined that the solar panels must be charging the batteries significantly faster than our chargers. Eventually we determined that all of the batteries connected to solar were "fully" charged by noon (or earlier), after only a couple of hours of good sunshine. 
  • We are not confident that our backup plan of manually charging each set of batteries on cloudy days is feasible. 
  • Ned noticed that the TRH fans sound like they are going bad at 1.5-m on relm and initb. 
  • We also noticed that rel1 2-D Gill is connected to port USB0, while the TRH is in port USB2. This was reversed on the sensor list on the Wiki, which has been updated.
  • I returned the Ubiquities on all towers to the 3-hr reporting schedule to try to save some power. This was done just after 1600 CST.

There will not be an IOP tonight, due to the weather. Hopefully the batteries will hold enough charge to make it through Friday night, as tomorrow should be very cloudy.

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3 Comments

  1. Steve Oncley

    If the lconvm charger was using its trickle-charge setting of 2A, it might not be able to keep up with the load and actually lose voltage.  At the 10A or 15A setting, it should have been helping.


  2. Matt Paulus AUTHOR

    Yes, I should have mentioned that we were using the 15A setting on the chargers. We are wondering if it could have been misinterpreting the charge status of the batteries and automatically switching to a lower setting before the batteries were fully charged. The disconnecting and reconnecting of the charger showed a huge discrepancy between what it reported before and after we disconnected/reconnected. We then attached the second charger and got a % charge in between the two reported by the first charger. It seems they are both measuring the "actual" voltage of the batteries, but interpreting the % charge differently.  

  3. Steve Oncley

    Looking at ncharts, it seems that lconv.m had no charging current during the period of about 1130-1230ish.  I would suspect that the charger wasn't completely connected or some such.  We have just suggested trying the charger that is in the base trailer (taking it to the field) instead.

    We've also just roughly recalculated battery capacity.  Deka 8G24 at 20hr rate: 73.6 Ah, Sunsaver cut-out at 11.7V corresponds to having used 80% capacity, operating at 0degC derates to another 80% = 47 Ah.  Times 3 batteries = 141 Ah. Divided by Iload of 2.5A = 56h.  Should be able to last 2 days...