Turbine charging systems...
Hi all, new to PPRuNe and hoping to get some clarification. I'm a piston pilot and working to transition to turbine. I'm curious about the typical turbine charging system and how it is configured do to conflicting information I'm getting around the airport.
I understand the ships batteries for PT-6 turbines are 24 v and around 40 to 50 Ahr and the charging system is 28 volt which makes sense given the generator needs to power the avionics at 24 Vdc as well as have reserve capacity to charge the battery during flight (similar to an automotive system that is 12 v with charging system that is 14 volts of output capacity).
My question relates to ground power supplies. I hearing that GPU's need to be 28 volt for starting but the ships battery is only 24 v? If that were the case, why wouldn't the ships battery be 28v too? Any insight would be greatly appreciated.
Thanks