Quote Originally Posted by mackrackit View Post
You might be right about the caps being unreliable, but the current is so low on the lines it might take some time to charge the battery pack.

Question - I thought RS485 voltage was negative without a signal on the line?

My original idea came from thinking about RFID chips.
If it is, then hook the battery up backwards
Seriously...I'm thinking that even a small battery with an intial charge on it would probably maintain thru the '485 line. And a '675 should be able to run on sub-milliamp current.
How often will the RX be powered, what's it's average daily 'duty cycle'?