Sounds like a cool project.I want to build a robot powered by 4 gear motors and a l298n motor driver
I am not an expert, but I do use Pi's quite extensively off batteries on a sailing boat. So, maybe my anecdotes might be of some value to you. Like you; I'm reluctant to buy expensive ready made HAT solutions, so; they are connected via SEPIC buck boosters to the ship's lead acid battery banks. A few of my observations.
1. I found that the Buck/boosters' specs can sometimes be a bit optimistic. I get round that by just buying much bigger than I need.
2. I found that the voltage drops can be quite significant. So, I use the fattest wires that I can physically fit!
3. You will eventually run the batteries down, unless you put some protection in. We don't worry about it because there are far bigger consumers like the fridge and freezer and they have protection built in so that they switch off when the system voltage long before the PIs get affected. But, you may need to consider that.
4. I don't use any UPS, so if the power was to fail completely; there is the risk of a improper shutdown...But for us, it's not really an issue...You might want to think about that.
5. I bought a little USB-C multimeter on one of the Chinese supermarkets...I find it invaluable for doing such things as you can easily see what is happening to the voltage..Cost me about 3€ IIRC.
6. I don't use a dedicated BMS because the ship has one anyway. So, I can't comment on that.
That's all I can think of right now.
Good luck.
Do come back and tell us all about it!
Statistics: Posted by kip_the_elder — Fri Jul 11, 2025 9:41 am