These are some more circuit board designs that are available. Just click on the link.
This one came about from my ventures into ebikes. It’s a plug in interface to the Dewalt batteries. This can be useful as a power source for Robotics as well as other projects. I plan to power an electric RC lawnmower with them. Dewalt interface Cost is posted on the link.
Smart Switch V4. This was created to provide a low voltage cutoff for ebikes. This also has many uses since it is easy to configure. Would make a good battery monitor for robots or any power device that you wish to shut down before the battery gets too low. It has no standby current or current drain when off.