As always, please proceed with caution in attempting any DIY mods.
NEVER insert the batteries and/or the battery pack incorrectly.
Batteries should be seen facing up NEVER down.
It could damage the Mekamon.
A bit of a background first…
I got hold of these amazing robots just a few weeks ago when they were listed for cheap on eBay.
Bought 2, and then bought another 2 a few minutes later - for parts, just in case.
I probably wouldn’t buy them in their original price.
When they arrived, it had the same problem as others reported, the battery has been fully discharged.
This began my journey to modding a power source.
Truth be told, this is my 2nd attempt actually.
Plan A was to replace the li-pos in the original pack with 3S 3.7V camera batteries and re-use the original BMS.
However that was short-lived as it only powered the Mekamon for a few minutes.
Voltage dropped quickly to about 7V from the fully charged 12v.
Perhaps, the batteries I used may not have sufficient power, maybe one of them is defective, or the internal BMS kicked-in and prevented the high-current drain.
I didn’t dugged much since I had a Plan B ready.
Anyhow, below is the Amazon part list I used for the battery pack mod:
- 3pcs 12V 10A 18650 BMS Charger Module Lithium Battery Charging Board with Protection 3S BMS Module
- Aodesy Plastic Battery Holder Case Storage Box 3 x 3.7V 18650 Black Pack of 5
- RuiLing 1 Roll 10 Meter (393 Inches) Nickel plated steel Strips for 18650 Li Battery Spot Welding 8x0.1MM(WxT)
- Heat Resistant Tape No Residue High Temperature Polyimide Tape 2 Rolls 10mm X 33m 100ft
The nickel steel strips can be skipped and alternatively a sufficiently gauged wire can be soldered directly to the protection board and the battery holder terminals.
Heat tape was used for insulation since the BMS mounts above it.
Other insulating tape should work.
I used metal folder fasteners for the battery terminal.
For charging, the OEM charger works well.
It trickle-charges when the battery reaches 12.5-12.6 volts.
The protection board should prevent over-charging, over-discharging, short-circuit, etc.
One thing to note though is that I cannot attest for their durability since I only have been using them for a few days but so far so good.
When charging, I temporarily just used alligator clips with magnets to connect to the jerry-rigged terminals.
I took note of the polarity of course.
With the terminals facing you, left is negative (-) and right is positive (+).
The 3S battery holder and the front battery plate requires some special trimming so they fit. The front battery plate/chest plate cover has a support lock that can also be removed without the need to cut anything.
Please see the pictures below:
Battery protection board wiring overlay (bottom view).
Note: heat tape used for insulation so the wiring doesn’t touched the board PCB.
Make-shift center channel sleave for protection and also helps with the alignment so it slides in like the original.
Foam fillers added also on the bottom and the sides.
Battery holder cuts (top view)
Battery Mod (top view)
Battery Terminal (front view)
Battery cover/chest plate
Note made some cuts for fit but the lock support can just be removed.
This will be a lose fit without a support piece though.
When done right, Mekamon lives!!!