Battery Size Estimation Calculations:
Battery specs depend on a few factors including power consumption of the robot, runtime of the robot, and continuous current draw of the robot. Based on preliminary estimates, power consumption seems to lie around 150W and current draw seems to be around 8A-12A (mostly dependent on the current draw of the Jetson Orin Nano). We aim to run the robot for around 5 hours, however, this increases the amp-hour capacity we need for the battery. Below are some calculations showing how runtime affects battery capacity as well as links to an excel spreadsheet and google doc containing everything I've done so far:

As you can see, we would need around 50Ah to run the robot for 5 hours continuously, and only 33Ah to run it for 3 hours. It is important to note that these numbers assume the robot is consuming 150W continuously which may not be the case.

Battery Constraints:

The height of the battery should be less than 5, 1/2 to be placed in the bottom compartment of the robot. If the battery is any larger, the frame design will have to be changed to accommodate the larger battery size. Width and length of the battery do not seem to matter (as far as I know!). This space constraint incentivizes us to use multiple smaller batteries and hook them up in parallel rather than using one larger battery, however, the capacity of these smaller batteries may not be enough to effectively support the projects needs. Below are some options I currently have in mind:

Option 1) Hook up Four 12V 8Ah batteries from lab (Model # SLA1079)

This would allow the batteries to fit under the frame while maintaining higher Ah capacity. This matches the project needs pretty well and uses batteries that are already owned, however, there are a few problems with it which I've listed below:

      a) With four batteries in parallel we can achieve 36Ah of capacity which can power the robot for only 3 hours continuously
          instead of 5.

      b) The current draw of the robot may be too high for the battery to supply continuously at a healthy level. The SLA1079
          datasheet provides us with a table that relates battery runtime and continuous current usage over time. It shows that
          continuous current should be lower if the battery is used for longer periods of time. This is to ensure battery health. Basically,
          if you run the battery for longer, you shouldn't draw as much current from it continuously, otherwise you hurt the battery over
          time. This table can be found in the google doc provided (I'd attach an image but I don't think the forum allows me to do that)

Option 2) Hook up Six 12V 8Ah batteries (SLA1079)

Same as option 1, but we increase capacity and current draw which solve problems a) and b). This could work, however, I'm not sure if we can safely connect 6 batteries, it may cause current draw issues. I will look into this.

Option 3) Purchase a larger battery

We could purchase a larger battery (40-60Ah battery to support 5+ hours of continuous use). This would increase the runtime of the robot as well as ensure the current draw of the robot can be easily managed. There are a few issues with this method though:

a) Increases the weight of the robot, potentially reducing mobility

b) The battery would be too large to fit inside the hull, so the hull would have to be modified to accommodate the larger battery.

Other Notes:

This is all the info I have now, but I'll keep doing research and figure out if hooking up 6 12V 8Ah batteries is safe, as well as looking into the current draw of both small and large batteries to see if they can handle the continuous current draw of our system.

Here are links to the excel spreadsheet and google doc with all my work. This information can also be found in the google drive.

Excel:
https://docs.google.com/spreadsheets/d/1c61AJ6dTo-TDHi3su-V8-ZS31RmROvyz_vDzj9C5zlU/edit?usp=sharing  

Google Doc:
https://docs.google.com/spreadsheets/d/1c61AJ6dTo-TDHi3su-V8-ZS31RmROvyz_vDzj9C5zlU/edit?usp=sharing