I personally have 3 SMC 24C batteries 1 of them 4100mah and the other 5200mah and one Dynamite 25C battery 6000mah. The 17.5 SC spec class at my local track calls for 25C max which is the reason I don't run anything higher than 25C. My 2 chargers are a Common Sense AC/DC balance charger and the Venom Pro balance charger. I run these on my B4.1 (13.5) and SC10 (17.5).