Originally Posted by
dsbrantjr
"The hub dynos are AC with no way to synchronize. "
One could run the dyno outputs through full-wave bridge rectifiers to convert them to DC, which could then be combined. However, the user would experience 2X diode voltage drops (2X 0.7V for silicon diodes) which would reduce the voltage from 5 volts to roughly 3.6V. If as suggested by Mr IGH non-grounded hubs are available all 4 could be put in series to yield 14.4V, which would charge a 12V battery. I am not certain that there would end up being enough power for any meaningful refrigeration system; perhaps one of the small solid-state Peltier module-based coolers could be accommodated..
You can't put the AC sources in series, they would need to be synchronized to work properly.
You need a separate bridge for each hub, floating input, sum two bridges into a single battery. Two hubs could charge a single 6V battery providing ~500mA x 2 or 1A @ 6V.
The hubs are really an AC current source, while the diodes add to the amount of power the rider needs to provide, they don't limit power to the load for all real-life cases.
I just looked at some coolers, the Peltier coolers need 5A @ 12V, that would limit the battery based system to 20% duty cycle at max power. I'm not sure if that's enough on a hot summer day.
edit; I'm finding some 12V, 3A Peltier coolers, that's starting to get reasonable but they're not big enough for a keg
