I recently bought a UDIRC Breaker drift truck, which has a long battery life for a 1/16 scale truck, but only comes with 1 battery as standard. These weren't available on Amazon, but we're a mere £9.99 at RC Geeks.
Ordered on the Sunday, delivered Tuesday for £2.49 delivery.
Exact same as stock battery. I now have around 40 minutes of race time from my 2.batteries.
Thanks RC Geeks