if you are using your ohm for intelligent octopus then (at least with the zappi) using it as a dumb charger is correct.
or is it different with the ohm than it is with zappi? my zappi does not talk to the car at all, when I want to charge I use the octopus app and tell it what percentage of the cars capacity I want adding.
so if the car is at 20%, I want to to go to 80% by 5:30am the following morning I go to the app, and request60% charge by 5:30 am then plug in.
the only minor wrinkle is we have 2EVs. octopus account is set up with the car with the largest battery
so my car has an 85kwh usable capacity,
my wife's car has a usable 28kwh battery.
so with her car if it is at 20% and I want to to go to 80% I basically divide by 3 as roughly my car has 3x more usable battery than my wife's.
so if I want 60% adding to the wife's car I request 20% on the octopus app.
but the charge point itself is totally oblivious it just adds what ever octopus tell it to add until either the battery is full or the car rejects the charge due to a failsafe charge level set in the car (a feature my car does not have as it happens)
if your charge is regularly going massively over what you want it to.... are you sure you have added the correct car to your octopus account. ? for instance a colleague of mine put the wrong Tesla model on his account which meant octopus thought he had a smaller battery than what he actually had (or so I am told by his wife) so their charge levels were wrong and he never got the charge he wanted..