After changing the battery in my TomTom 730 I now have an excellent battery life... but no Bluetooth. I can enable & disable it, but cannot connect to a bt device. When I try to scan it pops up no device detected without even attempting to scan. Anyone know much about the motherboard on the 730? Have I killed the bt module?

I had the same problem when I changed the battery on a GO 920, which is very similar to your GO 730. Didn't get the old battery hot enough to fully release the glue and (I suspect) broke a connection on the motherboard when prying off the battery. You might try visually inspecting for a break in the solder and repair it, but I wasn't able to find one on the GO I messed up. I now use a heat gun to heat the old battery to the point where it comes off with minimal effort. Torquing the motherboard will likely break something.

Silverhawk wrote:I now use a heat gun to heat the old battery to the point where it comes off with minimal effort.

I don't recommend using heat from any source. I've never had a problem removing an old battery with just a little gentle prying!!

Separate Battery from Circuit Board
The battery is likely stuck onto the circuitboard with some seriously aggressive adhesive .. some sort of contact cement material. It will be necessary to PRY the battery away from the circuit board. Be aware that there are no components mounted under the battery, so the use of a very thin screwdriver may help you out a great deal, but you MUST use it carefully. You don’t want to scratch any of the copper traces from the back side of the board.

Why so hard and dangerously??
If the battery is genuine it will glued on with some silicone like glue.
Replacements/refurbished devices can have a white contact type glue.
For both warming up the thing with a hair dryer helps to soften the glue - warming, not cooking!
And if someone would have bother to read my guide on it this someone would know that as a last resort you simply cut the plastic foil on the battery ;)
After that the actual battery can be removed, the left over plastic cut off and the new battery glued onto the rest on the circuit board.