Shell Cuts (for LiPo)
There are a handful of cuts you will need to make for fitting the AGBM-11 or AGBM-12 boards in a shell. This process may be different depending on the shell you purchase, but I've found most of the back halves of shells across various aftermarket sources are similar.
Also be warned that cutting into the shell may leave marks or whitened parts of the shell that can show through in transparent shells. Attempt this at your own risk. Also be prepared to do a bit of trial-and-error in doing these cuts, they're a bit hard to show diagram...atically?
(Remember: using an AA build does not require any shell cuts, gets you longer battery life with NiMH rechargeables, and won't be in danger of exploding!)
TIP: You can tell if you've shaved off enough of the PCB by placing it in the shell and seeing if it fits nicely, and that all the circled mounting holes line up nicely. If not, then you've got some interference somewhere.
[picture of mounting holes]
- Hand drill set
- File set
The USB-C port has to stick out in a specific location and that requires the circuit board to jut out into an area where there is shell interference. You need to shave off a few sections. Figuring out exactly where the plastic needs to be removed is easier if you actually put the PCB in the shell.
This is another view of the shell from the top-down. The boxed area is the same area as the top-right-hand-corner box in the above image. I sometimes use a drill to get rid of this section of plastic, just drill straight down and then clean it up with a file.
Cutting this hole into the shell is tricky and requires a lot of guess-and-check. What I generally do is drill holes on either side of the shell, and one in the center, then carefully shave away the shell until the USB-C fits. It's a lot of slow, procedural cutting. Here's some rough dimensions for where the USB-C hole is located.
This part will be easiest to check by putting the board with the USB-C soldered into the board. What I try to aim to do is kind of slide the board in at an angle to get the USB-C to fit into the hole. I don't normally shave off the plastic ridge so that I can place the board in straight down, because that causes stress on the plastic that can show through to the outside. I'll try to illustrate here:
[ diagram for placement ]
You also want to make sure the USB-C port is sitting in the shell gently, and not flexing the rest of the circuit board.
[ bend board example ]
There's a divider in the battery bay in some shells (OEM ones in particular) that are used to keep the AAs in place. Many aftermarket shells don't have this ridge. If you have it, you'll need to cut it out.