It is double sided foam tape under neath. only the foam is under the batt holder. you have to cut the pins on that batt holder at each end (which was designed to be soldered to wires) and make sure it is not poking out. After I cut those 2 pins, to be safe I put a small piece of plastic tape to cover them (putting a drop of epoxy would be better, but I was too lazy to do that
![Wink ;)](./images/smilies/icon_e_wink.gif)
). I soldered a black wire as (-) from the bottom of the holder which has a big hole with the negative plate exposed. and soldered a white wire on the (-) bar right under the bend where it goes into the black plastic.
the (+) and (-) metal bar you can just pull/push it out of the holder and do the cutting and soldering then put them back in.
A piece of thick double sided tape (that is my gyro mounting foam pad for my heli , available at HK ~5.00 for a piece about 5"x10 " double sided foam pad 5mm thick, that thing is very sticky and strong. I can pick up my heli from the little gyro with that little piece of pad underneath) just a little smaller to go between those 2 footing is holding the battery under neath. that area where the batt holder is and the double sided tape is, SKY9x board has no electronic components on the surface only circuit tracts.
What's not shown in the pic is to avoid any chance of shorting with a live battery. I stick a piece of tape right on top to cover all the shining metal parts on the top surface including the exposed batt surface.