Hi.
Does anyone have any schematics / sketches for multiple voltage measurement.
Looking to measure the voltage of several battery packs (say 3), but they don't have a common ground.
Indeed is it even possible?
Andy
Are they independent batteries or connected in series / parallel
It depends on the accuracy you require. The Arduino analog inputs have 1024 different levels they can measure. Call it close to 1000. If your total battery stack voltage is 100V then you can measure any intermediate voltage within the pack to 100/1000 = 0.1V accuracy.
The ultimate solution is individual chips mounted on each battery which are connected by a data bus with voltage isolation. There are some really clever chips available which will give you lots of data about each cell.
AndyGreen:
Hi.Does anyone have any schematics / sketches for multiple voltage measurement.
Looking to measure the voltage of several battery packs (say 3), but they don't have a common ground.
Indeed is it even possible?
Andy
The problem is one of measuring several voltages, and computing the differences between them.
So matched voltage dividers (1% resistors, not 5%), and several analog pins?
If the arduino is truly floating it will need a ground-reference to the lowest potential in the battery pack.