A heavy headlamp will ensure a powerful lightbeam, long runtime and a strong neck, all of which are good things. 
Ultraportable, affordable, HID, headlamp, … :-D
Cheers 
On the subject of headlamps, does anyone have any experience with the Convoy head strap? Is it comfortable when loaded with an S2+ or similar tube light?
18650 does have better energy density than anything smaller.
But if you compare 18650 light with 18350 + 2 spares, you arrive at pretty much the same numbers for both weight and capacity. 18350 variant will require extra work to change batteries, but can be used without spares for lower weight.
Nitecore NU20 CRI can be powered/charged via micro USB while using it, so with USB power banks the runtime is limitless.
I’d say it’s probably limited by the size of the power bank 
very good option!
Im a huge N219b fan. Have not seen a beam shot to know the tint or CCT of the LED in the Nu20CRI, but for my needs, which may not be the needs of the OP… I would strongly consider the Nu20CRI.
Now that we are including lights with built in LiPoly power and USB charging… the Nitecore TipCRI becomes a candidate because it comes with a clip that fits a cap…
Or the number of them. 
I have one, but haven’t used it for anything larger than an Hugsby AA and / or Olight S15R (I figure I might as well use my Wowtac A2 or Skilhunt H03 if I’m going 18650 size).
It’s comfortable for AA size lights, but is sometimes hard to get the beam to go where you want it to. There are two elastic bands on each side of the headband to hold a light (or two lights if you put one on each side) plus two bands on the top strap. The side bands only hold the light parallel to the headband, so it only points where your head is pointed. The top bands can be moved back and forth on the top strap, so you can point that light closer to where you want. It’s much easier to use the H03 and just pivot it up and down.
The headband itself is about the same quality as the Wowtac headband, and a little lower quality than what comes with the Skilhunt. I’ve found it much easier to use a light with a side switch such as the S15R as pressing on a tail switch moves the headband around, but then again I’m bald so your slippage may vary. I originally bought it so that I could use it with an 18650 while wearing a baseball cap, but haven’t had a chance to try that out yet.
They should sell them in pairs so you can look like Mickey Mouse… :laughing:
PS - On the lightweight headlight question, I have a Wowtac A2, Skilhunt H02 and H03, and Boruit RJ-02. Of those, the first 3 are fairly light and I’ll gladly deal with a little extra weight using an 18650 to pick up both brightness and run time. The Boruit feels heavy when I wear it, and it’s now the keep in the car for emergency use light.
However, the new Manker angled lights look interesting.
Thanks for this tip, i wasn’t aware of these tir’s. I’m a big fan of the h-03, but the spot is too narrow for me. Now I can remidie that
Do you plan to run with it on?
I have a Petzl Actik and a Nitecore NU20, which are both good for running forests at night (I use them for orienteering).
NU20 has built in battery so is only good for short events (can’t change batrery) or camping, but for those things it’s brilliant for the price. VERY light.
Petzl Actik is much more expensive and twice the weight but you can change batteries. You can buy a rechargeable 1800mah Li battery or 3x AAA. Good unit.
If you want more capacity than nu20 but don’t care about changing batteries I think the NU30 looks like a good compromise. Not an option for endurance events though.
DELETED due to lack of anyone reading, understanding or actually giving a rip
I have no Zebra lights (i think they take the ‘fun’ out of ‘funding’… ), but on my scales the H03 weighs 1.57oz that’s without the clip.
Did you replace the magnet with the plastic thingy?
Maybe it’s just me but I can’t understand the thought
of any of these popular headlamps being “too heavy” .
I feel like this is similar to saying a baseball cap is too heavy.
I just weighed my favorite cap. 86.4 grams.
It’s because it’s on your forehead, or rather suspended from your forehead.
The heavier the light, the tighter the head band has to be to keep it in place, increasing very much the feeling that there’s a thing on your forehead.
the H03 with short tube mod and aspire 18350 1200mAh has significant more capacity than 14500s and is below 100g with modded headband
i suggest a seperate battery pack headlamp if u want long hours. OLIGHT H35 WAVE is light weight, seperate 4 18650 battery pack, max 1500lm, hansfree activation, and if u say 3hrs 50lm is horrible then this has 550lm for 8hrs, 50lm for 24hrs :+1:
from my experience strapping a headlamp strap onto your head for more than several hours no matter how soft the strap is will still be very uncomfortable becos it blocks veins around your head. The best way is strap them onto a helmet then put them on that will be much comfortable