Fill negative space

[kerneldrop]

What are the best way(s) to fill ~3.5mm space between the battery's negative side and the tailcap spring? (Other than soldering and welding)

adding 1 penny to the negative side makes a reliable connection. 2 is probably better, but 1 reliably works.

The Acebeam IMR 18350 1100mAh that came with the light might already be a higher discharge battery. I can't find discharge details on the battery. I want to see if I can draw more amps or get a brighter output using a higher discharge 18350 battery. The higher discharge battery is quite a bit shorter

The Efest INR 18350 is ~35.95mm
The Acebeam IMR 18350 is ~39.72mm

 

[Lynx_Arc]

The only other thing I know of which isn't necessarily ideal is to use a small magnet. I think some put the magnet on and a little dab of super glue on the edges to help hold it in place. I'm not sure of the resistance added though as it could be enough that a very high current draw would be affected. I'll let some folks more expert than I am chime in on this. I think some have actually bought metal button caps that likely are the same ones used by button top cells and rewrapped them with the tops on them, but not sure how well that works.

 

[kerneldrop]

Thank you, @Lynx_Arc. I have various spacers from Oveready and Peak...but they are used on more conservative lights.
I wasn't sure how a spacer and a high current draw plays with together.

The light with the Acebeam battery works on high. No protection circuits cut on, so maybe the Acebeam battery is sufficient?

 

[john61ct]

Copper sheet or strip cut and wrapped around a button shape,

or just folded/rolled then flattened with a vise grip would be fine

 

[Lynx_Arc]

One other option I just thought of but not sure if it applies to everything is replacing springs with longer ones if possible.

 

[kerneldrop]

In the meantime while I look for copper sheets and springs:
I shined these pre 1982 pennies wit Flitz and a Dremel. They should be 95% copper & 5% zinc.
It took the resistance from .5 to .1

The diameter is a near perfect fit for the 18350 body.

 

[john61ct]

Then they'll do as is, so long as the uneven surface doesn't cause poor contact

 

[kerneldrop]

I'll swing by a couple stores to see if they have copper sheets. Otherwise I'll have to order online.

The light reliably works with the pennies...in general, does more contact perform better than less contact? Or is the goal for just enough contact for the light to work?

 

[Lynx_Arc]

I have a cheap 3AAA LED gooseneck lamp I got off Ebay that I took the spring out of the bottom and replaced it with a dime and got it to work with an 18650 battery. This may not be advised for all 3AAA lights as some you could burn out if they didn't account for the batteries lower internal resistance.

 

[xxo]

You can use a button or a nylon washer as a mandrel, cut a couple notches and wrap it with stripped copper wire, though I'm not sure it will work any better than your old copper penny.

 

[desert.snake]

I like magnets better, just cover the side of the magnet with electrical tape so that there is no accidental contact bypassing the switch if there is bare metal inside the wall of the lantern.

 

[DIWdiver]

Polished pennies are probably the best for ease of construction and quite good for performance, but if you have a tailcap switch, and the pennies short to the body of the light, it's like the switch being on all the time. Somehow you have to make sure this doesn't happen.

 

[kerneldrop]

Thank you for everyone's posts.

Luckily for this light (tk17vn) the battery compartment isn't bare metal. I assume the anodize will wear off and create a short to the body.

there's not enough room between the penny and the body to wrap it with electrical tape or shrink wrap.

i guess I need to look into soldering battery tops.
I don't want to get too overboard because Vinh has offered to solder tops and this light is the only one I have where it's designed for a taller battery and draws a higher current.

 

[DIWdiver]

Also, don't forget that newer pennies are no longer solid copper. They are copper-plated zinc. I forget what year they changed over, but it's been quite a few years. Pre-change pennies would be better.

Edit: they changed in 1982.

 

[kerneldrop]

I searched for pre 1982 pennies and lucked up on a '73 and '74.
They shined up really nicely
The 1793-1795 are the good ones! I don't have any…

Finally this jar of coins that my kids spill every week came n handy

 

[Lynx_Arc]

I searched for pre 1982 pennies and lucked up on a '73 and '74.
They shined up really nicely
The 1793-1795 are the good ones! I don't have any…

Finally this jar of coins that my kids spill every week came n handy

I don't recall ever seeing a 1793 penny I wish I had a few of them they are worth about $13,000 each.