First post in the community, so forgive me if I'm in the wrong place. I'm looking to build a battery discharge cycle tester to determine how fast certain devices drain batteries. I'm planning to use an Arduino Zero to command the system, but I'm unsure of which exact circuit configuration and components would best suit my needs. The system will basically act as a programmable DC electronic load that can be varied during each cycle (ex: draw 20 mA for 3 mins, then 60 mA bursts for 1 min, then off for 5 mins, and repeat). I also need to be able to continuously measure the voltage of the battery pack to stop the test if a prescribed low voltage limit is reached, to simulate the voltage being too low to power the theoretical device.
I'm fairly familiar with how everything works, but I don't have a ton of experience with circuit design so I could use some advice. I've found two example circuits on YouTube (pics attached), but there's some variation between them. If I'm going to be working with a max battery voltage of 12V and have to draw a max current of roughly 300mA, but be able to accommodate as low as 1.5V and 0A, which circuit would work better? And what Op Amp(s) and MOSFET would be a good choice? I'm hoping to use a single supply Op Amp that the Zero can power, but I can figure out another solution if this can't happen.
Please let me know if there's any important info you need that I left out. Thank you so much in advance!