MN82 LC79 18650 Battery Box

Gives a snug fit in the original battery location.
No modification to the body required.
you only need to desoldier the wiring from the old battery - if you dont have a spare set on hand already.
Batteries might fit a little tight but insert from the spring side first (Dont mess up the pollarity!!!). - This helps alot with contact while the car is bouncing around.

Requirements:
- 2x 7mm(W) x ~10-15mm(L) springs,
- Wires, leads and plug to connect to the vehicles harness (I just desoldiered the ones from the old battery)
- 6mm nickel strip or even a strip from a soda can will do (Just sand off any coatings).

Print:

- PLA or PETG
- No Supports
- 0.1 Layer height but that's just my preference.

Steps:

1. Desoldier the leads from the old battery and de-pin the blue / balancing wire from the plug - you dont need this anymore, Unless you are planning on using the original 3-pin charger. - Be careful not to puncture or overheat the old cells. Just peel off the outer shrink wrap on the pack.

2. Print the model, to make it easier to get the bridging strip in, Pause the print right before it seals off the strip side. Insert the strip and continue the print.

3. Once Printed, gently thread the wires on the plug through the holes on the spring side. I added markings for + and -. It helps to have a pick to direct the wires through on the other side:

4. Once the wires are through, tin your springs and wires - give them a little sanding to help the soldier stick - remember to use flux or flux core (flux core is easiest). Remember: Red = (+), black = (-).

5. Soldier your wires on the inside of the springs as best you can - give them a gentle tug to make sure. then gently pull the wires back through the holes till your springs are seated. - I gave mine a drop of filling powder and superglue at the base just to hold them in better.

6. Test fit your batteries, if they are catching on the strip, you can use a file or lighter to gently edge off the corners on the pointy bits. - cut off any excess strip that may be sticking out the side of the holder. you can cut the springs down to adjust the compression but be carefull not to leave any sharp edges.

UPDATE:

The points for the metal strip were a bit sharp / long, causing batteries to get stuck. I updated the design to use pins instead. Just use a small flat screwdriver to flatten the strip onto the body with a little superglue behind. now batteries fit much better / smoother and arent too tight.

Disclaimer:
- These mods are done solely at your own risk for the purpose of DIY and experimentation. This design is shared purely "As-Is" and the designer accepts no responsibility for any direct, indirect or consequential harm, loss or damages.
- Working with 18650's (or any LION or LIPO battery), while generally safe does come with its own risks. - Always do your research.
- Always use a proper charger designed for use with LION or LIPO batteries.
- Never mix capacities (i.e. dont use a 500 mah cell with a 1000 mah cell) this will result in one of your cells being over discharged and may damage or overheat it. Always use cells with the same capacity (i.e. 1000 mah cell with a 1000 mah cell).
- Do not short the batteries or reverse polarity, always make sure you adhere to the polarity shown on the holder. If the protective sleeve or housing of your battery is damaged, rather just replace them.
- If your battery capacity is over 1200 mah, it is recommended to invest in a bigger / better charger. the standard USB charger migh not have the output to charge the batteries correctly.

Happy printing and many happy miles!.