There are thousands of concrete mixers to meet different needs among both construction site and households.
https://betonniere.cn/?p=88
For households, 100L to 200L with 0.55kw electric motor is the first choice since diesel generators can power it without any issues.
For construction site, concrete consumption capacity is much bigger, so we have to choose diesel engine powered heavy duty type concrete mixer with 500L,600L drum size because one bag of 25kg cement is needed for mixing. Some shops might sell 400L by lying that 400L can also mix one bag of cement, which can not be realized or testified.
During mixing, some mixers vibration is strong, so pls test run before purchasing.