Bill, if you been reading my comments, I think it may be overkill, but here is are systems available today which can do what you want, and it downlinks a bunch of other parameters as well. I think it needs a HUD but it is a start.
sfsjkid
Thanks the web sites were very interesting. Incidentally it has been over ten years since my last battery related crash.
General field SAFETY
The somewhat hidden agenda in my comments is general field safety over the next ten years. Unfortunately one individual can only improve field safety by about 1%. General solutions might improve safety by 80%.
All flight fields seem to have a few who are reckless with batteries. Fields also seem to have another large group who simply don’t understand battery technology. There is yet another group who are sometimes good builders and good flyers who are convinced that anything electrical is too complicated to learn. All three groups are not going to spend money on solutions when the problem is not recognized.
If the radio manufactures were to believe battery voltage represented greater safety maybe in ten years 80% of the transmitters in use would display RX voltage. Those who don’t understand and the too complicated group would quickly and unknowingly become knowledgeable by glancing at the transmitter RX voltage. It wouldn’t take long to gain an understanding of the significance of decreasing receiver voltage. Cause and effect could be closely correlated.
Everyone including the safety officer could closely monitor those who are reckless. At our field there are a couple of reckless types that could be monitored by walking to the flight line and glancing at the in flight voltage. If the reading were near the knee on the battery curve we could request they stop flying. If they didn’t stop flying they could be given their walking papers for safety violations. With the current system there is simply no way of knowing when the reckless are getting into trouble.