Review: Haikelite HT35, a high-powered zoomable spotlight

A full album with extra images is available at https://imgur.com/a/AlaL6

Quick Review

The HT35 is a large, 2x26650 zoomie with an XHP35 emitter. While beginners often think they want adjustable focus, I consider it a specialty feature better suited to those situations where a spill-free spot is desirable. Applications that come to mind are photography, signaling to indicate a specific object or location, some types of hunting and use as a makeshift followspot.

Haikelite advertises 2300 lumens and 1000 meters throw. I got 2060 lm and 808 m. I think this light was originally intended to have an XHP35 HI emitter rather than the domed XHP35 it comes with; if the HI was used for the original throw number, that would explain the discrepency. The HT35 is still a respectable thrower with its neutral white tint and lack of spill helping to reduce backscatter. Tint is very uneven across the beam with the exact appearance varying based on zoom setting. In general, floody settings are cool white in the middle, warm white at the edge and a gradient between. A HI emitter would probably help with this. Color quality is otherwise average.

Build quality is acceptable, but not great. There are some sharp edges, and unsurprisingly for a zoomie, long-term immersion in water is not a good idea. It did survive a brief dunking and adjusting from flood to throw to create a vaccuum, but a drop of water made it past the seal under the lens. Longer immersion under those conditions may have resulted in water damage. The light is simply described as "waterproof" without specifics, and should be OK to use in the rain and around water, but intentional immersion should be avoided. The head can wobble at some zoom settings, which is not confidence-inspiring, but hasn't caused any trouble.

The user-interface is a simple reverse tail clicky. Click on, half-press to change modes. There are only three, with no blinky modes and no mode memory. It starts in high if it's been off for more than a couple seconds. It's not clear if there's thermal regulation and extended operation on high can get very hot. Output did fluctuate a bit near the end of the uncooled runtime. It's up to the user to switch to a lower mode if the HT35 gets too hot and the manual says as much. The heat is not extreme, and I think user comfort will be the main reason to adjust brightness rather than any harm to the electronics. Output is stable as the batteries drain until the low-voltage stepdown and eventual shutoff.

I don't think most peoples' lighting needs are especially well-served by a big, powerful zoomie, but the HT35 may be the best option for those who have an application for such a light. Its high, stable output, respectable throw and passable waterproofing are rare features in that class, and the addition of a tripod mount should make it more appealing to photographers or anyone who wants to improvise a vehicle mount.

    • Stable output as the batteries drain
    • Passable waterproofing
    • Enough output that the huge flood setting is bright and useful
    • Neutral white option on a zoomie is very rare to see
    • Falls short of advertised throw
    • Severe tint rainbow
    • Sharp edges
    • Advertises 18650 as a battery option, but they do not fit without spacers, which are not included
    • Coil whine
    • Body/head connection wobbles

Details and technical analysis

Accessories

The HT35 comes with a carry strap and a lens cloth.

Modes and user interface

State Action Result
Off Full-press High
On Half-press Cycle modes (H->M->L)
On Full-press Off

Output and runtime

All tests were conducted with Sony VTC6 3000 mAh 18650 batteries unless otherwise noted. The HT35 is intended for use with 26650 batteries, which have capacities as high as 5200 mAh. It's reasonable to add roughly 70% to these runtimes to estimate performance on 5200 mAh batteries. With a mechanical switch, there is no standby drain.

The HT35 has no (or minimal) thermal protection and uses a boost driver able to maintain constant output in all modes. Output is nearly perfectly flat for the entire runtime until the low-voltage blink warning. There is low-voltage protection at 6V, or 3.0V per cell making the use of unprotected cells low-risk. I consider the runtime over when the light starts blinking constantly regardless of output, as it's not very usable for illumination at that point.

Mode Advertised Lumens Estimated Lumens Throw (FL1 meters) Graph Advertised Runtime Time to 80% Time to 50% Time to 10% Tailcap current (mA)
Low 250 290 303 - 32 hours - - 12.5 hours 239mA
Medium 700 865 542 graph 8.5 hours 188 min 188 min 188 min 845mA
High 2300 2060 808 graph 2.5 hours 51 min 51 min 51 min 3300mA

Additional graphs

Light quality

One of the advantages of a zoomie is the ability to have a spot of varying size and relatively even brightness. Unfortunately, the tint is not even. To my eyes, it's about 6000K in the center and 4000K at the edges. Side-by-side comparison of lights with known CRI tells me the CRI of the HT35 is around 70; it does wash out colors and obscure subtle differences.

There is no PWM on any mode.

An 80 CRI XHP35 HI would greatly improve this light, having both better color quality and a more even beam pattern. Such emitters do exist and I expect I'll be upgrading mine with one.

White wall

Outdoor

Ergonomics

The HT35 fits nicely in the hand and has comfortable rings of knurling that provide sufficient grip. The tailswitch is easy to press, however, the guards around it have sharp corners that are quite uncomfortable to put any pressure on. I found the big ring for the carry strap a bit awkward as well; fortunately, it's removable given sufficient torque.

Batteries

The HT35 claims to run on two 26650s or two 18650s. Unsurprisingly, 18650s are a very loose fit without spacers, which are not included. The unprotected, flat-top 18650s I used for testing were also too short to make contact consistently. Short 26650s might also have contact issues. Protected 18650s do fit comfortably.

I wouldn't complain about 18650 not working well if Haikelite didn't advertise this light as being compatible with 18650, but they do. Longer, softer springs would probably help here. 20700 might work, but I have none and did not test it.

Modification potential

I've decided to start including modifications in reviews. Some people just can't leave well enough alone, and I'm one of them.

ToyKeeper has mentioned a couple times that whining noises in flashlights are often produced in the springs. I wondered if bypassing the head spring would reduce the whine the HT35 produces. Unfortunately, it did not.

As I believe this light was intended to have an XHP35 HI, I thought it important to test one, even though I do not yet have the one I want to use long-term. The bezel unscrews easily allowing removal of the lens. A plastic retainer can then be unscrewed to reveal the pill and emitter. It's a heavy brass pill with enough mass to be a decent heatsink.

I used the cool white XHP35 HI I removed from an Acebeam L16 and got these results:

  • Oputput: 1920lm (30s, flood)
  • Throw (FL1, max throw): 1059m
  • Throw (FL1, max flood): 98m

The tint is very harsh, but the beam pattern is more even, and the throw hits the advertised number. Output is marginally lower, but not by enough to matter. I'll definitely be putting an XHP35 HI in the HT35, but not this one. Kaidomain has a nice 5000K 80 CRI that even has a half-decent flux bin. Of course, I'll lose a little output, but output is overrated relative to color quality.

White wall