I tested this mod and maybe you need to change the powersettings:
In my base with 1000 roboports & 20.000 robots (working) it is using several GW extra power. I dont like that it

https://wiki.factorio.com/Roboport - Internal buffer recharge rate 5.0 MW

This mod doesn't change the roboport's charge rate, but minimizes the time of robot charging from the already charged roboport.

How to get even faster charging time ? (and whange roboport buffer if you know ? ^^)

It can be done, but it can be a little too cheatty for me.

The buffer size can be higher, it will be added as an option.

The Construction robot has internal buffer 1.5MJ, Logistic robot has also 1.5 MJ.
For four robots we are need 6 MJ, for 10 robots we are need 15 MJ internal buffer size.