I recently upgraded one of my Solo Controllers to the larger battery. Now I have a spare, 7.2 VDC battery that I probably won't use.
My stock Skyviper battery is labeled as 3.7 VDC, and weighs 27 grams.
My stock Solo Controller battery is labeled as 7.2 VDC (two internal cells), and weighs 95 grams. Unwrapped, the fully-charged battery looks like this.
Let's say the Solo Controller battery could be disassembled and one of the cells could be carefully soldered to the stock SkyViper battery connector for longer flight times.
I can see a few potential downsides to this idea:
(a) the cell does not physically fit the SkyViper battery holder, and the Skyviper would not be level if the cell was simply attached to the SkyViper battery holder,
(b) the cell should be aligned to the Skyviper's body and securely attached to maintain center-of-gravity of the SkyViper,
(c) there may be a mismatch between the cell and the stock SkyViper battery charger (assuming that the Solo battery's circuit board and most of the wiring was removed, leaving only the red and black wires for connection between the cell's terminals and the stock SkyViper battery connector). A different battery charger with the correct connector may be needed or desired.
(d) the additional weight of the cell may outweigh the additional energy of the cell, resulting in minimal improvement in flight duration.
(e) the cell presents a larger obstacle to wind or speed, compared to the stock Skyviper battery.
(f) the SkyViper may need to be fully re-calibrated because of the mass and position of the cell. (A reset to "factory" settings may not be sufficient.)
(g) this mod requires good soldering skills, and the electrical knowledge and will to risk a LiPo fire due to accidental shorting of connection points or exposed wire ends.
So... does anyone see a significant problem with doing this mod, other than maybe doing some work that may not result in enough benefit? Has anyone done it yet?