Nitecore NWL20 Design Flaw Don't Buy 

Love mine great little light. Mine had the same problem. Simple fix: stretch the spring problem solved.

It would be helpful if you clarified whether or not it was a Nitecore brand protected 21700 cell, versus another brand or unprotected.

Looks like they fixed that flaw in latest version, battery sits absolutely tight, it's 21700 battery with protection board (that adds few millimeters to battery length). I also have Convoy with 21700 without protection board, I tried to put this battery in NWL20, and as I thought it's too small, doesn't even touch both contacts. So if you want to have spare battery for NWL20 you should buy protected 21700, most likely it will fit, if not - use the coin. By the way, both batteries work fine in Convoy S21E.

Phew I recently near to buy, but you saved me Hopely they quickly replace it or recall the products on the market as soon as There you go, Thank you mate Btw, Just wondering how about if we use the flat top battery? Does it fit and still functioning?

Is that with the supplied battery?

i considered this, LedLenser W6R Work and the Olight Swivel Pro and ProMax. thanks for the input, i ended buying a Fenix CL26R.

Try using a Fenix 21700 battery, it is a bit longer

Sounds annoying but it seems like an easy fix? Can stick a stronger spring in there

Same problem as mine, fixed by putting a five cents US coin on it's (-) end, no more rattling

I have the same issue. The battery doesn't fit well but overall happy with it.

i just wrapped electrical tape on the battery it fixed the flickering. the battery indicator is still faulty on my unit though..

Can we add a copper washer to remove the slack?

you just saved my money. Thanks. I'll wait for an upgraded version (if any in the future)