The RedRotor RROSD has a built-in current sensor that allows the OSD to show current and mAh without any effort on the part of the user. This is, in my opinion, one of its strongest selling points. But many people on the RROSD support thread on rcgroups say that their current sensor is inaccurate. RedRotor has actually added the ability to calibrate your current sensor by +/-20% in response to these requests. But I've always found my RROSD current sensors to be perfectly accurate, when compared to my meters, and I've suspected that something may not be adding up.
The problem is that people are determining the accuracy of their RROSD current sensor by looking at how much charge their battery charger puts back into the battery. If they draw out 1000 mAh and the charger puts back in 1200 mAh, they conclude that the current sensor is inaccurate. I'm suspicious of this approach.
The RROSD combines a PDB and OSD in one. The main advantage of this is that the current sensor has to be on the PDB, so co-locating it with the OSD keeps everything neat and tidy. You can purchase the RROSD here:
