Need a new brighter headlamp battery system. Lack of bright lamps caused our climbing party to get off route on the descent so many times we spent the whole night getting back to our car.

The 4 of us had all different kinds of lamps, BD, Thrunite, Princeton Tec etc.
What we didn't have was enough changes of batteries to shine a long distance for a long time to avoid being cliffed out. Everyone had plenty of light to see 50 feet or so, but we needed to be able to see a full rope length - 200 ft. for several hours.

Do the li-ion rechargeable batteries have high output longer than others?
regular lithium disposables? Alkaline?

I would say it depends entirely on the cell. Some are better than others.

Definitely depends upon the cell and its Mah (milli amp) rating which ranges frequently from 2600 Mah to 3500 Mah in 18650 batteries. The higher capacity cells are more expensive, but in my experience well worth it. One trade off is that they wear out sooner, so I am told

Becoming available are 21700 batteries and associated lights which are rated at 5000 Mah.

For night excursions in tricky terrain, I like a lower power headlamp, coupled with a higher power hand held light for those interesting sections.

Basically you want rechargeable lithium ion batteries in a light with variable light levels, pretty common these days, but they ain't cheap!

The short answer is yes. The current state of the art batteries are 5000 mAh 21700 cells, but while these are available in headlamps, they are fairly massive for that purpose, and not something I’d want hanging on my noggin, if I could at all avoid it.

My Fenix PD36 TAC uses a 5000 mAh 21700 and is rated to run for over 10 hours at 350 lumens, which gives a beam distance of 302 feet. The Fenix HM70R headlamp has a 500 lumen mode with a beam distance of 325 feet that runs for 6 hours. The HM70R weights 7.27 oz with the battery installed. But, that’s their newest model. You won’t find much out there, if anything, that beats it.

Be advised that some lights are designed as "throwers" and can spot items at a distance and others are 'floods' for nearby overall light.

The marketing folks always talk about maximum lumens, but these are often only available for relatively short bursts. Pay attention to the lumen level sustainable for at least an hour or so.

LED choice, size of reflector and optics generally dictate how far light can throw.

That's why see some headlamp designs with multiple LEDs, one set specifically for throw/spot and rest to provide area lighting/flood.

I've found you get brighter, or you get longer. You don't get brighter-and-longer unless you also accept bigger-and-hotter.

For my lights that take multiple battery types, if I need max longevity (not storage time longevity, but longevity during use), I put NiMH in them. If I need max brightness, I put Li-Ion in them. If I need long storage time, I put primary lithium in them. And I always have a few of those Costco "alkaline 5 bazillion battery packs" laying around for long duration power outages where I wouldn't be able to recharge anything.

Your specific use sounds like you need a very narrow focused beam pattern headlamp (lens) equipped with a corded external battery belt.

Yeah, or both. Here's one that has a single central LED for regular use, and 4 outside for a spot and is powered directly off a USB powerbank.

https://flashlight.nitecore.com/product/hu60

I recharge during power outages with portable solar panels and power banks. A generous supply of rechargeable batteries, loaded and ready to go, is also a plus.

I have dumped all alkaline batteries - obsolete technology

Its actually milliamp per hour, not just milliamp.

https://en.wikipedia.org/wiki/Ampere_hour

Just like your home electricity is kiloWatt/hour(s).



You could have a 2 AA battery pack with a 2000mAh rating or a lithium Ion Battery pack with with a 2000mAh rating.

You can have LEDs which are more efficient than others and give more lumens of light per mAh consumed.

You can have different lenses and reflectors that make the beam wider or more focuses as well.

So, unfortunately, there is not a direct answer as to which battery technology will have longer output unless you eliminate other variables, i.e. have the same light with adapters for different technologies.

You'll find that different technologies might be able to provide more energy compared to their weight https://en.wikipedia.org/wiki/Rechargeable_battery#Types but what often happens is electronics utilizing a battery type with a more efficient power to weight ratio are often use physically smaller cells so you get a similar amount of runtime from both. Think how a smaller car might be more efficient mpg wise but have a smaller tank and a larger car, while getting less mpg, will usually have a larger tank so they can both typically drive the same distance before needing a fill up.

I used to standardize on AA powered devices, be it lights or GPS or camera, and a carried a pack of spare AA's. However I've begun to transition to USB rechargeable devices, not only for the smaller size and weight, but also the ability to have them all connected via the smallest/lightest USB cables I can find, and keeping those devices always connected via those cables to a battery bank in my backpack. Could that be an option for you as well? Do you carry/wear a backpack on outings?