Logging increasing sensor data via Arduino nano with HM-10 BLE to a phone app


I am very unfamiliar with the propagation of data with Bluetooth low energy (BLE) but I remember reading somewhere that it can only accept char values.

At the moment, my project makes use of a ACS 711 hall effect current sensor to monitor current being provided to or from a battery every 30 seconds. Now I would like to store the positive current values when the battery charges into a float type variable that constantly increments itself by each new charging current value and be able to send that to a phone app via Bluetooth.

I understand that I am going to need storage since this number is only going to get larger past the memory limit available by the Arduino nano.

My question is how would I go about doing all this sensibly? Should it be best to be doing the arithmetic on back end framework of the app and just have the app receive char data constantly every 30 seconds?

Should I implement an SD card so that I can write this large variable into it with the BLE just sending the last generated current charging variable to my app?

Any insight on code implementation or storage ideas would be greatly appreciated.

Thank you

I get the impression that datalogging with BLE is more trouble than it is worth, but it is possible.
This might help, and also
God only knows what a back end framework is but storing is usually a good idea, and SD is an obvious choice for it. What you store is your choice, it may depend on the receiver, rather than Arduino.