Anybody with a little lab equipment -
o A couple of regulated DC power supplies equipped with Current and Voltage meters
o A DMM
o A resistive load that will give a current load of an ampere or two at 12 volts
- can perform a little 'lab' experiment to experience what the 'power system operators' experience ... connect all devices (2 power supplies and the one load) together using any suitable set of test leads or wire ... switch on the power supplies and adjust the first one for twelve volts as seen at the 'load' (the big resistor) ... this first supply will be carrying 'all the load' presented by the resistive load.
Now bring up the second power supply slowly ... attempt to achieve 'load balance' now with *each* supply carrying half the full-load current ... your success in LARGE PART will be dependent on *how fine* an adjustment you can make with the voltage adjust poteniometer ...