How difficult is it to remove the spring from the driver, and solder a pedestal of round copper stock in its place? I have the BLF A6 and I really want to do something a little different.
Not too hard. It’s easier if you add a bit of flux then hit it with the iron until the solder melts and twist or slide it off to break the suction.
^ +1, Flux is the answer for most soldering problems.
To remove springs I always set my iron to max temp and leave it the least amount of time possible.
there are brass pins you can solder on, forgot whether they were at banggood or fasttech. They come in a pack of 10
I’ve noticed the springs on the BLF A6 are really weak so if you replace one with a pin it might switch modes when you bump it, might be fine depending how you use it. Could also go with a stiffer spring on the other side which would help stop that annoying battery rattle (I put O-rings in mine to stop the rattle).
This is what I was looking for, thanks.
One thing I really like with my BLF A6 is the double spring idea because it cushions the cell in both directions should I (heavens forbid) drop it. A post would not do that and would transfer the full weight of the cell to a small point on the driver board which could be a problem for the driver or the cell. Or would it? I don’t have enough experience to know that answer.
Mine also has a weak spring up top- shaking it hard won’t change modes but a decent bump on the tail will. Handy for a quick mode-change but a pain when you don’t want that to happen. Both springs should be equal but they’re not so what I’d like to do is install a new spring of the same kind as is on the tailcap, or if I can’t find that exact spring I could install 2 new equal ones. And while I’m in there a double spring bypass seems worthwhile. Any ideas on obtaining the spring(s) I need to do this would be appreciated.
Phil
Actually I have seen drivers break from dropping even with springs, although they were very cheap buck drivers (the inductors crack) and the light was dropped a lot. Both the springs on mine seemed to be the same but that could be due to the switch in production half way through. I just put some copper braid on both springs and and placed an R-10 O-ring at either end of the battery. The O-rings are the perfect size to just clamp an unprotected cell with just a little bit of pressure and keep it from moving. I hadn’t thought about driver damage from dropping but this method places all the impact force into the body of the light and prevents any bump switching. For springs Mountain has a few good choices and the carobronze springs from FT seem popular aswell.
I’ve just replaced the factory springs on my SRK as the Mtn 7135 driver was drawing enough current to overheat and soften the factory springs.
I used the “carobronze” springs scianiac mentioned above and did a test run on high until the head of the light got too hot to hold. The springs showed no sign of issues or discoloration from overheat.
Thanks for the responses. My light has a much weaker spring at the tail but I’ll do both to keep the pressure equal. I may do the spring bypass anyway since I’ll be in the neighborhood. Got to get my soldering equipment overhauled now, nothing bigger than a 25W pen working here ATM till I go for the butane torch which will be a bit much for this job.
Phil
Is there anything other than a coil spring that would work to put pressure on the battery, assuming a wire bypass was used to carry the electricity?
I’ve seen miniature “shock absorbers” made for example out of a short piece of plastic tube with little lengthwise cuts in the middle, leaving both ends solid.
So under no pressure it’s cylindrical; under slight pressure the strips between the cuts bow out (or if the cuts are tapered to make space inside) they can bow in) slightly).
Hit them and the little strips bow more and spring back.
I guess that would be like several leaf springs loaded at the ends with the middle free to flex. Hard to describe, haven’t found a picture.
I don’t believe it’s feasible in metal. The point at which the leaf spring strips connect to the ends will undergo too high a degree bending. Also the material at that point needs to transition from curving along one axis to bending in a different axis, requiring more elasticity at the edges than metals have.
Yeah, I wasn’t thinking these have to be made of metal — figuring a spring bypass would carry the current around the thing so it doesn’t need to be metal.
I was thinking of something that wouldn’t lose strength from heat and stay springy for physically holding the battery firmly.
Something to avoid the problem noted earlier in the thread — that using a solid brass pin as the contact transmits all the force of a shock to the cell, maybe denting it or damaging the driver.
There are a surprising variety of possibilities out there. Just for ideas, not dropin things we could use off the shelf probably.
Tho’ these are about the right size and meant for reflow. Only rated for 1 amp tho’ — but probably there are others along the same line
or other kinds of springs
or even these flexible couplings, meant for wobbly shaft connectors but they do compress like springs — with a lot more mass:
I used the 2mm brass piece from international outdoor once but after a short research about different resistances I now use a simple solderblob.
If there are no parts on the underside(like the a6 driver) a really flat one is enough to make sure that flat top batteries also work….not to mention that I usually use a bigger solderblob on the batteries as well.
I ordered the 1mmx5mm brass pieces from intloutd to try on some batteries but they are out of stock and the ones I got are 0.4mm thick
So if someone has a source for these copper pieces I would be glad to get a hint.
You can find small copper discs on Etsy. here is one example:
Copper Disc 14g 8mm diameter Blank Cutout for Enameling Stamping Texturing, listing #97126760, 2mm thick ,100% pure solid copper.
Just go to Etsy and search ‘copper disc’.
Copper is a much better electrical conductor than solder, brass, or rare-earth magnet.
Yup,good idea!!
why you want to remove the spring from the driver?
Because the springs have resistance, no spring has no resistance….so for a hotrodded light you need to bridge the spring with a cable/copper braid for maximum current or you simply remove the spring.
hum~