Costco Mario Kart RC - Replacement Batteries - short video

How to build replacement batteries for Mario Kart Mach 8 Mario and Luigi RC Cars, 2-pack - SHORT VIDEO
Costco - Mario Kart Mach 8 Mario and Luigi RC Cars, 2-pack - replacement batteries.
Costco sells this Carrera Toy. But either on their website or on Costco are no replacement batteries available.
(www.costco.com...)
I build my own replacement batteries and explain in the video how to do it.
If you want to see the long version of this instructions, please watch:
• Costco Mario Kart RC -...
Please note, everything shown in this video is for entertainment purpose only, I do not take any liability for anybody which attempts to copy or follow what I did. Please follow the manufacturers recommendations.
I bought the batteries from Amazon:
batteries 3pce $11.99 when I bought them : (www.amazon.com...)
I bought connectors from Amazon:
20 pce $6.99 time of my purchase
(www.amazon.com...)

[@Oravankarva]

Can i combine the 3 batteries together? Just soder them on to one cable or will that make problems? I don't want to replace the battery individually every time when battery dies.