I have seen very random voltage drops from FloatHub that also generate alerts, showing voltage at a much lower level than is actually true. I have at least 6 other systems monitoring the voltage, and none have shown any of these drops. Several of them are connected to the same fuse block the FloatHub is using, so I suspect there is something going on with the FloatHub.
Wow, SIX monitoring systems; the first step is admitting you have a problem 
Looking over your data logs and plotting the voltage:
We do see some downward spikes, but they look to be associated with declining voltages. If we had to hazard a guess, looks like a fridge coming on once a day or something similar.
We’ve experimented in the past with averaging algorithms to smooth the reported voltage, but many users prefer alerting off raw data. Best option is probably to offer an averaging option in the details part of voltage alerting dialog (something like a checkbox that says to average the readings over the period being tested). Another one for the To Do list, thanks.
Yes, I have a lot of monitoring systems It is a disease of sorts.
I am using LiFePO4 batteries, so the voltage is very very consistent, and the fridge itself uses an optimizer product so it shouldn’t be drawing that much at startup. There are other pumps such as the water/bilge pump, and the head which has a high speed pump/macerator.
Sounds like an average might be better though.