I posted a question regarding a tool and power supply to a few different platforms, but came to the similar confused responses. So I believe I have went wrong somewhere and wanted to start from beginning of how I got to where I am now.
It started from this youtube channel.
First lesson I learned from this guy is that power supply and charger terminology is often used wrong. Stating examples like power adapters and bricks for labtop is a power supply, not a charger. The charger is often inside a device. Like inside the phone and labtop. It looks like a little circuit board usually it seems.
Second lesson I learned is that power supply controls the voltage which I believe "pushes". Charger controls the current which "pulls" and voltage can be lower when charging a discharged battery. So that got me to understand charger should not have higher voltage or current than power supply to be safe. Too much voltage will charge past battery max storage overtime. Too much current can pull too much than the power supply was designed for.
Which leads to the original reason why I learned this. I have a drill and power supply. Picture attached below. I wanted to change the 120vac to DC power supply to 110vac to 250vac to DC because I will be using it in different countries.
This is where I got confused. What I "learned" didn't seem to make sense anymore. Charger in drill voltage and current is higher than the power supply. But that can't be, because it works just fine. Something must be wrong here. I decided to look for other solutions for now.
Finally, this led me to an idea of using a power supply left around the house. I found this.
It accepts 110vac to 240vac. The lower voltage is okay because it is lower than power supply. My understanding is it would charge little over 50% because the max on charger states 8V max and it would stop charging around 5V. I believe the 8V isn't the actual battery capacity, but it must be close to it.
So to sum up, I have 3 questions.
Question 1. Is my basic understanding of power supply, charger, voltage, and current wrong?
Question 2. Why does this power supply and charger work without issues?
Question 3. Can the 5V DC power supply charge the drill?
edit: Thank you everyone. It was difficult to pick what helped the most, but I appreciate all the help. I see where I went wrong.