You have not planned well for the battery and the servo. All you did was adding a centre differential to a "AWD" without making room for the rest, ie the motor, servo and the battery.
All I know is, as someone has suggested, the CG will be too high and the motor must be placed near the floor. Looking for the right cells will be your first step now. Stop all other work first.
i have planned the servo , but still i can't a good battery.
can you suggest some kinds for me?
by the way, i have take some picture for your reference.
this is the battery and the height of the motor.
1. C123 battery is never a good choice (Ultrafire?). They are too big and the the factories are usually exaggerating the capacity (mah).
2. You have difficulty adding the servo and the PCB.
1.but they can provide high current and long time to use.
do you have some kinds of battery that suggest me to use?
i am really a stupid about the battery.
2. i have managed the room for adding the servo and the pcb. so don't worry about it.
3. i want to ask ...a silly question. if the 2 battery weight added together is bigger than the motor, then the cg is still keep at the lower bottom of the car. is it?
so cheap?(is it like the cell phone's cell?)
how about the charger?(can i use the standard charger for 1/10 to charge it?)
and how long can it be used?
what is the voltage.
if it is good, i want to get two too. do you have more?
You wrote:
2. i have managed the room for adding the servo and the pcb. so don't worry about it.
3. i want to ask ...a silly question. if the 2 battery weight added together is bigger than the motor, then the cg is still keep at the lower bottom of the car. is it?
2. But the PCB will add to the tall CG (I can understand there must be ways to make the car steer.)
3. Your motor will be at the top of the body shell. Let me tell you it weighs about 19 grams. Try adding 19grams at the top of the body shell of a normal AWD. See how it runs.