I'm building a little TR-801 for a friend, with an 8-chip 105C (so the battery side of the board is populated). The catch is, I only have ~65mm long flat top unprotected cells here to check with, and he plans to only ever use longer button top protected cells. With a normal (inverted) long spring on the driver, a 70mm cell isn't going to fit.
The workaround that might save it is if the button is tall enough to contact a solder bump on the driver in place of a normal spring. 7135s are about .055"/1.4mm tall. What's a typical dimension for button tops, from the wrapper up to the tip? Knowing that number will determine how tall the solder needs to be to make contact before the wrapper bottoms out on top of the 7135s.
In case anyone is going to try measuring with a micrometer, be careful to not short the + to - :(…. I just tried, trying to be careful with an insulator on the + end, and ended up shorting it. Micrometer’s still ok, but looked like it damaged the battery (a new Ultrafire, so not too worried).
Sorry comfy, but maybe someone else will do it :(…
I don't have any button top protected cells to measure. I know the max is 70mm, but I don't know how much is the body, and how much is the button.
If the distance from the top of the cell body at the wrapper to the tip of the button is 1.4mm or more, it will fit no problem with a dab of solder instead of a spring. Say, overall length 70mm, length of cell body not counting the button 68.5mm, button height 1.5mm. Those numbers would work. If the body is longer and the button shorter, it probably won't fit - the body of the cell around the button will hit the tops of the 7135s before the button makes contact with the driver.
Measurements taken from the light, I have 2.656"(67.46mm) from the tops of the 7135s to the tail end of the tube (tailcap seats flat across the rear face of the battery tube).