herbQ
This may help some of your questions. Sounds like if you trickle charge it will have to be to hybrid battery.
Toyota.com : Hybrid Synergy View : 2005 : Fall : Maximum mpgs
GS: Yes, they need to have enough of a charge to start the engine the first time. After that, the batteries are charged by the vehicle's systems. Every Toyota hybrid also has a battery similar to the one in a conventionally powered car, but it's used only for 12-volt accessories and to power the vehicle's computers.
Bob
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2009 Tacoma PreRunner Crew Cab. Wife's Car
2009 Camry Hybrid, Mine :
2008 Harley Davidson Screaming Eagle Road King-My Bike
2005 Harley Davidson Deluxe-Wife's Bike
1998 Honda Accord EX (Daughters, but I bought it)
2009 Corolla LE (Other daughter but she's paying for most of it)
Photos located at
http://community.webshots.com/user/currybob