I'm using this instead of a BEC on my 500 FBL, having suffered brownouts with the FuBar controller powered by the 4A SBEC on my ESC. I used a Hobbywing 8A BEC for a while, but then started using these LiFe packs. They are a perfect fit under the battery mount, and have twin servo leads which means they can definitely supply the amps when needed. I can get up to ten 5 minute flights from a single charge, but usually charge them after six flights, when the charger puts back around 500mah - so the average current draw is only around 1A.