Interesting fyi, I added 22 AWG wire bypasses on the springs (short ones in the center of the spring), and got ~ 25% boost in lumens and candela.
Measuring amps at the tail, on a charged up 40T the amps went up from 14.7A to 16.5A, but that's only seeing the bump of the bypass on the driver side because my amp measurements are with the tailcap off. I did the before/after tests with both a 40T cell and a red Dolidada 5500 26650 and saw about the same percent bump. These springs are not high performance, accept maybe for their thickness but they are not low resistance. The bypass on the tailcap spring probably made a greater difference in amps based on the lumens/throw measurements.
Yeah, but I've added bypasses on many unsoldered springs and always get a boost. I do cleanup the contact surfaces though, clean with isop. alcohol then applied a light coating of NO-OX-ID. Dunno for sure it makes a difference though. Was think'n of using 20 AWG, could have, but the 22 is easier to work with and hopefully should last longer with better flexibility. These are classic budget springs, unlike Hank's lights or FireFlies. Even the Haikelite's and the better Astrolux's use double spring for their high amp setups.
It's just something to look out for. They got a high performance driver in there so I knew there had to be something else suppressing the amps/output. They got a nice MCPCB, so for high amps, it's got everything except the springs.
Actually look'n at my notes, I got a nice bump on the EC01, though not as dramatic, maybe ~15%.
I added a bypass on the Sp33V3 tail spring. You can pop out the spring - usually just a good pull gets them out - there's nothing holding it down except for a slight recess at the bottom. The you solder a wired from the top (usual) to the bottom rung of the spring, keeping the bottom rung flush on the bottom. I've done many of this type as well.
I assume it’s not much different from bypassing the “springs sprung into a tailcap” seen on many E-switch lights. I recently was briefly confused by it on my Boruit D10.
Another goal I’ve had with my more recent spring bypasses has been to try to fill-in the top hole of the spring, when practical. I noticed MTNE drivers, if purchased with a bypassed spring pre-installed, are done this way and I like it for the possibility of reduced contact resistance. I know if I really cared I should put a brass or copper contact pad at the top instead…
Yeah, I haven't used the buttons on springs, but I do try to fill in top hole. I'll use a small file to flatten out the top. Also for a tail spring like this, there's usually extra solder bumping out on the bottom and I'll file that out smooth, flush with the last rung, as well. Solder is easy to file down.
Interesting. So essentially this is an additional electrical pathway on the spring… and somehow this provides a little power boost. Very curious. It makes me wonder why flashlight makers don’t fashion a spring with a wire connector like this by default, so they can claim even better specs.
It’s handwork, it reduces spring travel, solder may scratch the battery terminal. Many reasons. Maybe better to use double springs, don’t know. I’ve seen a nice solution by putting some copper wool into the spring. If it was copper wool, that is.
Edit: I’ve seen a Sofirn with bypassed springs, IIRC.
It's all about resistance to maximize amps. On buck/boost or linear amp controlled drivers, usually makes no difference. Some lights are shipped with spring bypasses, some with double springs. If you unstretch the coil of a spring, you got a long wire. Steel is a very poor conductor so the electricity only flows through the super thin coating/ Beryllium copper springs are much better than the vast majority of stock springs.
There's other conditions, such as a highly compressed spring has less length to flow through, etc. I've seen bypasses make little to no difference.
FET drivers benefit the most, but of course if you swap a high performance FET driver into a light, the stock spring may not be designed to handle the high amps -- so, the bypass prevents the spring from a melt down.
How much extra output do you think you got out of the SP70?
Ever done an L6? I’m surprised how much more output I get from the SP70 vs the L6, considering they both use the same batteries and LED.
All the Best,
Jeff
I own both - Stock, the L6 doesn’t have a FET driver, which is where bypasses give you real gains. Additionally, it used to come with XHP70. Knowing Simon, they may come bypassed these days - he’s no stranger to bypassed springs, at least.
The SP70, despite our best efforts at communicating the importance, did not come with goo BeCu springs, nor bypasses, nor doubled springs. But it did come with a FET! (And even there, I recall DBCustom getting an increase from a better FET.)
When the amps are high enough, I even bypass BlueSwordM springs… like on my Supfire M6, 3xXHP50.2 3V build.
I will be posting a review of the SP33v3 this weekend, if all goes well with my schedule. It’s a terrific flashlight, well thought out for the most part, and a true “pocket rocket.”
