Spring bypass.

Hey guys.
Just pondering a driver and switch Spring bypass. Is it something that's worth doing? Am I correct in thinking it will only make a difference when in turbo (direct drive) or will it make a difference in all modes? Also
How much of a difference does it make?
Finally what is the best way to approach a bypass and is there anything that I should watch out for.
It's the stock switch in a Convoy C8 with A17DD driver.
Thanks guys.

I'm not sure of the current draw of the driver itself from the battery to give you an idea of the resistance difference of the spring itself. I've seen others bypass springs with heavy wire, also I think solder wick too. What you need to do is measure the resistance of the switch itself probably using a digital meter and compare it from spring to switch to etc to see if the spring is adding much resistance to the circuit and using ohm's law you can calculate the voltage drop through the spring &/or switch.

If it flows too free it may zap your LED module.

bykfixer said:

If it flows too free it may zap your LED module.

Click to expand...

Really? What would cause that? I've noticed when looking on some sites they offer bypasses as an upgrade option, surely they wouldn't do so if there was risk of frying the driver without posting a disclaimer? I'm just curious as to whether it's worth the effort? I've got a reel of 15A cable so I would use that as I'm pretty certain a single XML2 powered by a single 18650 wouldn't draw that much current.
The way I've seen be advised it to de solder the springs completely and then solder a length of wire or desolder braid to the board, replace the spring over the wire then solder the other end to between the first to coils so I'm wondering does the effort justify the results or am I unlikely to notice a difference. Or would I just be better purchasing a couple of heavier gauge, lower resistance springs?

I've done a few spring bypasses, they're easy to do and effective.
Before you go down that line, check the temperature of your springs (I use my tongue) after a few minute of Turbo. The resistance of metals increases with temperature. If the springs are cool / warm you are OK. If not consider the bypass.
I use the same wire that I use for wiring to the Led Star, can't remember the SWG, but there's plenty of info on CPF. You're only using 1/2 inch or so of wire so you won't need a high gauge wire. Also it needs to be almost as flexible as the spring, otherwise you wouldn't need a spring in the fist place.
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Ok so I ran through 6 consecutive turbo cycles and the spring was fairly warm. Think I'll pop to my local electronics store as the wire I have is not very flexible. Am I better with thin wire or desolder braid?

I use Silicone Wire myself.
There's a chart of wire sizes and current ratings here...
http://www.3tronics.co.uk/product-page/46343e52-8561-306e-fb26-8edd6e8647a1
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I've had my best luck with solder wick. Is very flexible even at the solder joint and has plenty of current capability.

Yeah i ended up using solder wick. Went for the 1.5mm wide stuff. Was significantly cheaper than any spool of wire they had in. I ended up by completely desoldering the spring from both driver and switch the soldering a folded length to the middle of each PCB placed and soldered the Spring back over and then soldered each length of wick to both sides of the Spring so now there's a V of solder wick in the middle of each spring. Plenty of current capacity. Also one notable difference is now when on turbo mode the head gets notably warm (but not hot) by the end of the 30 second timer which I can only assume means there's more current hitting the LED as before it never got any sort of warm.

Well done, so glad it worked how you wanted.
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Would be interested to see what it's throwing out now. Given its a thrower that I've tailored to have more spill/flood it still throws a fair distance with a nice bright fairly diffuse hotspot and a lovely smooth flood surrounding it. Getting a bit carried away with lights and modding now. Got more on order and am now bouncing around waiting for it to arrive even though it was only ordered yesterday!

Welcome to the madness.
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A easy way to check the difference is to just unscrew the tailcap and bypass the whole switch. Put some thick metal on the - on the battery and the end of the body. It will help bypassing the switch and driver spring on the fet dd drivers. How mutch is depending on your batteries. How mutch Amps can your 18650 deliver?

It's a VTC5a so about 20-25A CDR. I've pulled 40-50A from them when vaping and they took it in their stride. Damned good batteries. Although all that said batteries don't give out a current, they have a current drawn from them based upon the resistance of the component to be powered and the voltage within the cell.