12V Ride On Cars

Guys-

Excuse me for posting in the wrong area. I am new and need help. I have a 5 year old little girl that loves her 12V Ride On Jeep I bought for her last year. Unfortunately, I did something stupid and ruined it. I've seen hundreds of videos on YT of guys doubling power on the Jeep by connecting a 2nd 12v battery. I tried doing that and I heard a loud POP. Now it won't move. I don't know anything about motors and engines. I need some help to replace the motor. 

Please point me in the right direction. Thank you.

There is probably an inline fuse that is burnt out.

Also make sure you didn't hook up the batteries such that you sent 24V to the motor.  One way of hooking up the batteries (parallel) keeps the voltage at 12V. Another way (serial) adds the battery voltages and makes 24V.  A third way shorts the batteries to each other...not good. Be sure of your wiring and measure the voltage at the connection to the motor. Unless the videos you have been watching really intend for 24V to go to the motor, only 12V should be at the connection.

Yeah hopefully just a simple matter of replacing a fuse. Can you post some pics of the car so we can see what you are working with?

I recently upgraded my son's Power Wheels Quad to Milwaukee 18V Lithium battery power. Our battery was dead and a new one is $100. I have two Milwaukee 5.0 AH 18V batteries, so I decided to give it a go.

I bought an adapter for the Milwaukee battery that runs to a positive and negative 12 gauge wire. On the positive side, I installed an inline fuse (40A), and then I put everything through a motor controller. I cut the original power wheels battery adapter plug off and connected it to the motor controller. Aside from blowing a few 30A fuses before a I stepped up to the 40A, it works great so far.

Here are the parts I used:

Milwaukee 18V battery adapter: Milwaukee M18 Battery Power Mount Connector Adapter Dock Holder w 12 awg Wires https://www.amazon.com/dp/B07Q71H57D/ref=cm_sw_r_cp_api_i_wGT2EbEKAEH6B

In-Line Fuse:  WirthCo 31820 Battery Doctor... https://www.amazon.com/dp/B00DQ5JRUA?ref=ppx_pop_mob_ap_share

Motor controller: Sydien DC6-60V 6V 12V 24V 48V 30A... https://www.amazon.com/dp/B07GGTZXH1?ref=ppx_pop_mob_ap_share

In hindsight, I could have skipped the motor controller. You can only get to about half speed through the accelerator pedal, and then you twist the hand grip to get full power. It works kind of like a two step, so they don't get too much power just by hitting the gas. Otherwise, it would probably wheelie when starting off.

They are generally pretty easy to work on.  The motors can be had even on amazon for cheap. 
My boy has a razor 24v quad thats stock, its a bit much for him for now. He mostly uses a 6volt bulldozer that i have runing on 12v, no issues from the motor with hours of use. We have a 12v powerwheels jeep that is stock for now.

Just look up  550 motor on amazon. 
 

that reminds me, you may have blown the forward/off/reverse switch or pedal. I hd both blow on the double voltage bulldozer. Unless you arced something i dont think you would have popped a fuse. Fuses care far more about amps than volts. 
 

same as the motors, you can usually find the switches and pedals on amazon cheap. 
 

do you have a pic of the jeep? Curious if its the standard powerwheels jeep. 12v and a motor/gearbox on both rear wheels.