This post here should make most of the battery use clear. I had recently set up my own BlueRov2 and found this to be one of the most informative posts.
When charging you don’t need to stop the charger at 14.8V. If following the guides on the product pages correctly you should be charging in Lipo mode which if you let it run its course fully at the recommended 10A, it will reach about 16.8V (I find it reads slightly higher initially) and then it will maintain this voltage while the current drops off from 10A to 0A. The charger will start beeping indicating the battery is 100% charged.
I’ve found this quite confusing also in regards to some of the specific battery terminology and to the fact it is a 14.8V battery but full charge is 16.8V etc. Maybe someone else with more experience could provide a better explanation for understanding it. What I had found was it is to do more so with the inability to accurately measure Ah’s so voltage is used as an estimate as it is much easier to measure.
Running the battery down to 12V or the 3.0V per cell is the recommended minimum not to exceed. Different people have their own stopping point though as some recommend not going below 3.2V or even as high as 3.6V per cell. Again someone with more experience may have a more conclusive answer.
A simplistic way I have taken it as is 4.2V per cell (or for the blue robotics 4 cell battery a total voltage of 16.8V) is “100%” charge and if you take 3.0V per cell as your stopping point (or 12V total) then this would be your “0%” charge. While in fact the battery isn’t dead (0V) its at its point where it needs to be recharged (0% useable battery left). Its like your battery should be taken as working from 16.8V to 12V (100->0%). If you decide you don’t want to go below 3.6V per cell(or 14.4V) then this would be your “0%” battery left and so on.
For discharging/storage the recommendations are to discharge to 3.7V per cell (14.8V overall). There is a mode on the charger that will either automatically charge or discharge the battery to this voltage depending on if the voltage is currently below or above this. I had completed this operation once before and found it was discharging at 0.1A, quite slowly. This is recommended for long term storage but maybe someone else could share their own experiences in regards to their usage or define “long term” more specifically.
The guidelines are important to follow as you don’t want to damage the battery or at worse risk fires so make sure to read the product page learn sections and other links.
Did you get video to display in the end?