I have a stock E-Starter 300C 10x8 prop and using 2s E-tech 1200 total weight comes to 14.5 oz flys just fine. full power- 8-10 mins 2/3 - 10-14mins. Also Aeromicro is selling the 2S E-Techs for 26.75 I also use the Hobbico MKII Charger (49.95 at Aeromicro) for my Lipolys works just fine for me. I use a wattmeter to monitor the charging.
good luck
Mike
www.aeromicro.com