is there a reliable source of charging current?

I am testing several chargers and cables to find the optimal combinations for a fast charge.

I was so far using CurrentWidget and was getting just a few values, (independently of how much the battery is charged, for several cables and the same charger, as if there was no losses, etc.). I then tried Charging Report which was giving the same value, but also a "Max" and "Avg" one.

I finally discovered that these values most probably come from

/sys/class/power_supply/battery/current_*

Since in my case Current > Max (1698 vs. 500) and the max current I get is always 1698 mA (and it is always that for a given charger) I have some doubts about the accuracy of the reported values.

Should I trust them?