6PL/17670 Issues - help?

I have enjoyed my 6PL and have experimented with a couple different drop ins as well as the stock P60L and on primaries have been quite pleased.

I have tried a Dereelight 3SD (runs only on one li-ion) and the P60L on a 17670 from AW I had around to use in my HDS tube and it does not run well. Not from an output standpoint but with both drop ins I get a flicker using the momentary tailswitch (it is the standard Z41) that I don't get with primaries and the P60L or another multi power drop in I have (a Dereelight Q2 5A). On constant it works OK but still can flicker a bit with movement.

My 17670 is a bit shorter than two Surefire primaries stacked, or my AW 18650 as well so it seems like this short difference may be the culprit.

Any ideas on how to remedy it or do I just need to get the body bored for 18650s (which may be the best idea since I have a few of those as well and would all things being equal prefer to use them - I was just trying to use the 17670 I had which doesn't get used that much)?

Sounds like the shorter 17670 cell is creating an intermittent contact with the Z41/P60L.

I would try and lengthen the 17670. I have never tried it before but others use neodymium magnets to extend the length of the cell. I think it would be safer to place the magnet at the -ive end of the cell, that way it won't short +ive to -ive across the cell.

I just tested a C2/Z41 with a new P60L and both size cells (17670 / 18650). No problems.

Unless the cell is dead/drained, the culprit is likely the P60L (weak spring?) or the switch.

What is odd is that with 2 primaries it works perfectly with the Dereelight drop in as well as the P60L ... only has an issue with the 17670 (which has been charged I believe 3 times since purchase from AW and shows 4.12v on the multimeter...) but has it with both drop ins and that cell. With primaries I tried to intentionally wiggle around the switch to make it flicker and it worked fine.

I may give Surefire a call tomorrow and see if they'll send me a replacement Z41.

kramer5150 said:

Sounds like the shorter 17670 cell is creating an intermittent contact with the Z41/P60L.

I would try and lengthen the 17670. I have never tried it before but others use neodymium magnets to extend the length of the cell. I think it would be safer to place the magnet at the -ive end of the cell, that way it won't short +ive to -ive across the cell.

Click to expand...

I think magnets and lithium battery cells are a bad idea. Not just because of the possibility of a short causing catastrophic failure, but the magnets also tend to mess up the cell internals itself.

for btter spacers you might make thse
https://www.candlepowerforums.com/threads/242371

Gatsby said:

What is odd is that with 2 primaries it works perfectly with the Dereelight drop in as well as the P60L ... only has an issue with the 17670 (which has been charged I believe 3 times since purchase from AW and shows 4.12v on the multimeter...) but has it with both drop ins and that cell. With primaries I tried to intentionally wiggle around the switch to make it flicker and it worked fine.

I may give Surefire a call tomorrow and see if they'll send me a replacement Z41.

Click to expand...

I doubt its the Z41. The Z41 is no more than a moving piece of metal with an o-ring on it. Seeing as you're not using a SF lamp or battery, I don't think the SF warranty covers your situation. The only thing that could go wrong with the Z41 is it could get dirty. Stuff the edge of a folded up paper towel saturated with IPA into the crevice and wipe out the junk. Might help to use a toothpick or other slim device. Considering you said it doesn't have a problem with primaries, I don't think the switch being dirty is the problem though... If all still fails, gently stretch the spring on the Z41. Its highly unlikely that its become compressed, the problem likely lies in the drop-in's spring combined with the shorter length of the battery. A new Z41 would likely exhibit the same characteristics.

The Z41 is pretty much the most failproof piece of equipment you could buy.

An easy way to test if its the switch is to create the problem configuration, then remove the tailcap all together. Run something between the - on the battery and the lip of the body. This connection is all the tailcap does to complete the circuit. If the problem is still there, its not with the Z41.

Stretch the center spring on the drop-in.

Then bore the light for 18650's!

ElectronGuru said:

An easy way to test if its the switch is to create the problem configuration, then remove the tailcap all together. Run something between the - on the battery and the lip of the body. This connection is all the tailcap does to complete the circuit. If the problem is still there, its not with the Z41.

Click to expand...

indeed...

I had an issue with a home made drop-in, the batt, the L2M body and the Z41...the 18650 batt went so far as to BARELY make contact with the Z41 spring...just enough to let current through but contact was not taht firm so there was a bit lower output...The only way to run the combination is with a spacer...

I have this problem with the Z59 when I under-power a buck-regulated LED module and it has to do with the contacts in the switch being worn out/oxidized. The solution is usually to disassemble and re-surface/clean/lube contacts.

ampdude said:

I think magnets and lithium battery cells are a bad idea. Not just because of the possibility of a short causing catastrophic failure, but the magnets also tend to mess up the cell internals itself.

Click to expand...

x2... I don't like the use of magnets or anything loose to extend cells. I have also wondered about magnetic forces affecting cell chemistry.

Stretching the drop in spring would be the easiest solution. The OP should be made aware that the Z41 spring is a PAIN to get back into the switchcap (at least thats what I have found).

kramer5150 said:

x2... I don't like the use of magnets or anything loose to extend cells. I have also wondered about magnetic forces affecting cell chemistry.

Stretching the drop in spring would be the easiest solution. The OP should be made aware that the Z41 spring is a PAIN to get back into the switchcap (at least thats what I have found).

Click to expand...

Sadly I discovered that last night before your post! Some pliers and patience eventually won the day, but it was not a lot of fun...

I'm not sure it has made much of a difference unfortunately. I bought it locally and have thought about just exchanging the whole thing - see if that solves it or not but that should eliminate the host as being the culprit. I just can't figure out why it works so much better with two primaries - I tried teh 17670 in my Novatac tube and it worked just fine and it tests fine. I may work with the drop in springs as well since it appears that the length is somehow the issue.

I tried the same combination of drop in and 17670 in my Dereelight CL1H (the P60L doesn't fit very well due to the spring so it was only the two Dereelight drop ins) and they both worked just fine. Obviously the CL1H is a clickie and not a twisty - and theoretically is designed for the drop ins although the Dereelights are supposed to be fully P60 compatible. It does seem to have something to do with the 6PL host.

Did you try the test that ElectronGuru mentioned?

That will tell you whether the switch is the culprit.

kramer5150 said:

the Z41 spring is a PAIN to get back into the switchcap

Click to expand...

I've found that its best to use just a small screw driver. 1) Find the end of the wire where the wide end of the spring starts. 2) Place that in first, and push it against the side wall. 3) Place the screw driver 180 degrees away from that point, and push down.

The start of the spring has more friction and the screw driver tip is small enough force the other side in without dislodging the first side. With practice, this technique is about 60% (per attempt) successful.

I had the same problem with a solarforce with a dereelight drop in. With primaries it works fine. It was intermittent with an 18650. The length of the cell was the culprit. I used a magnet on the negative side of the battery to lengthen the cell. It works like a charm.