P7 on handlebar switching modes..

[mimis]

this issue has probably come up times before but never settled to a solid answer (or i've lost the thread..)
Having mounted a Trustfire P7 on handlebar i've been dealing with front wheel vibration causing repeated mode switchings while it lasts. Same problem with both my P7's.. It has been suggested here to insert a small coin or other metallic plate between spring-battery, didn't work..
Has anyone solved this ?

 

[znomit]

Yes batteries are slightly different heights so some aren't as tight as others and so there can be some bounce, a shim will help with this.

Also maybe give the light a tune up?
http://www.candlepowerforums.com/vb/showthread.php?t=227518

 

[mimis]

thanks znomit for a very helpful link but i think i'll try the shim option first. What exactly kind of shim will do the job and is between spring and neg battery pole the place?

 

[Illum]

sounds like the circuit is way to sensitive to momentary contacts

I'd consider trying a small flat rare earth magnet between the battery and spring. Most of the time I found tail springs to be something magnets have no problem holding on to. Plus a magnet ensures better contact over simply acting as a strainer

 

[Linger]

It has been suggested here to insert a small coin or other metallic plate between spring-battery

Just take care you don't create a short...a piece of metal touching the negative battery terminal and the side of the body wall will by-pass any tailswitch.

similar to shims, you could also try thin o-ring around the batteries. This will hold them latterally (while the switching is caused by movement longtitudinally); however it is free and will reduce the 'bounce,' hopefully enough to eliminate your problem.

 

[mimis]

thanks guys for the nice tips, now help me please because i messed up already!
I duct taped the battery body -to reduce bounce -as thick as to allow it easy inserting the tube and.. how stupid, i can't figure how to pull it back out!

 

[Linger]

oh snap...

I'd just like to say I hear your frustration. It's a blow when you accidentally take your equipment off line.
(and now you see why o-rings work better eh?)
Do you have any rubber straps? I wonder if can get at if from the top. Can undo the top of the battery tube (the section below the bezel where the driver is). It's probably glued. If all else fails, you'll likely get two chain / strap wrenches and give at it this way.

Can you get at the tape at all? pick it apart from between the cell and the tube?

Post a pic maybe...

 

[mimis]

ok, i used a bobby pin to pull the battery out and of course i damaged it as i tore its cover in pieces.. anyway linger, what's different if i use an o-ring instead, it's battery jammed in again. What's the right place for the o-ring?

 

[Linger]

If you've got to force it in, it's too big (i.e. will have to force it out).
If it's jammed, use a thinner ring. O-ring just around the cell, should allow it to slide in / out yet not rattle around inside. This should be an easy mod.

 

[mimis]

ok, problem fixed. I duct taped the battery again but left a little strip of the tape jogging from the pos pole like a tail of the battery that's used for pulling the whole thing out.
MT P7 now works flawlessly and i'm a happy night owl..