ORIGINAL: nonstoprc
If the output voltage of one regulator is slightly higher, its battery pack will provide the power most of the time.
The use of dual regulators actually prevents the other battery from kick in unless the voltage of the pack is dropped lower than the output voltage of the other regulator, which does not happen often with pattern load.
The above is based on a discussion with Smartfly tech support rep.
The output voltage of the two regulators is what determines if they share the load equally, unequally, or not at all. The dual regulator setup that I use and that most customers use is for equal load sharing. The two main reasons for that are that you are getting use from the weight you are carrying, and you also have a positive indication that everything is working, based on what you observe each flight. The regulator's output voltagehave to be within .005 volts of eachother,or less in order for this to work well. If anything fails on either side, the other keeps it all going, without any loss of power whatsoever when that occurs.
If all you are interested in is an emergency backup without equal load sharing, what I call a hot standby, then the precision of the regulators is notas important. But why carry that weight unless it's doing something for you? Viewed another way, if you want to carry about 1000 mils of useful capacity, just carry a couple of 480's, not a 1000 and something else.