The thing to remember about some electrical equipment is "Will you be there when it does fail?". So working on stuff in the lab or stuff that's only on when you are there to hit the kill switch and/or the fire extinguisher you can play "I'm a big boy, it doesn't frighten me, I know what I'm doing", all you want.
![](https://img.memecdn.com/trust-me-i-can-do-worst-than-that_o_3795933.webp)
The stuff that you want to leave running while you are out of the house or in bed or that you will leave running while your children play in the house, needs
far,
far more respect.
On topic. When taking readings from the MPPT charge controller, remember it will vary the power it takes from the panel by varying the voltage across the panel. As the battery nears fully charged with no load on it it will allow the panel voltage to rise out of the MPP and the current to fall to balance the charge current to the battery. With a fully charged battery and no load on my 50W panel the voltage will rise to open circuit voltage and the panel produce nearly zero power, even in direct sunlight (in reality it produces the battery float trickle power). I think the only way to really test the max power output is to saturate the load with a load that will pull more than the panels can theoretically achieve. At least enough for the battery to be providing some of the power. Even then it varies a lot due to insolation.
Also, excuse me if I read wrong, but your charge controller support 12V and 24V systems and claims a maximum of 100V. I'm fairly sure this does NOT mean you can run 100V of panels into it. It simply means that when it raises the panel voltage to lower the power your 24V panels can produce at most 100V safely and not fry the charge controller. Some panels produce close to twice their optimal voltage when open circuit, so that would be 48V and stating an upper limit of 100V just sounds like engineering grace (doubling), not an excuse to run 100V of panel into it. 4x12V panels open circuit will hit as high as 80-100V leaving zero grace on that limit.