Mercedes shuts down the vehicle homepate so for the 451 ther is no possibility to control the car online. Lots of user are searching for alternatives:
There are a lot of tinker solutions but for me it would be much better to use a professional base like OVMS.
Odyssey from Germany found a lot of CAN ID and Messages for this car and made a small toll to chekc battery data. Documented here: https://github.com/MyLab-odyssey/ED_BMSdiag
They also found a solution to seht the preconditioning https://github.com/MyLab-odyssey/ED_BMSdiag/issues/17
If there is a programmer who will implement the code for the smart, i can buy a hardware and test the program.
I am not a programmer but i make small applications with arduino, so i can read codes and make small changes.