there arnt any round here thats why im asking if there are any rear wheel conversion kits anyone could recommend ive got a new 36v 15amp battery
They're all much of a muchness. The bigger they are, the more robust they are, but they're heavier too. The Q128H (up to 7 speed) or Q128C (8 spd or more) are very good, though not legal, but you have to buy them from China (BMDBattery, Topbikekit, Greenbikekit). Without special requirements, any one will work for you, so buy whichever one you want.
One thing you do need to keep an eye on is the speed. 201 rpm is 15 mph, 260 rpm is 20 mph and 328 rpm is 25 mph. with a 36v 15A battery and controller, there's no point in going over 260 rpm because you won't have enough power for the motor to run efficiently.