Imalent RT90 Luminus SBT-90.2 Flashlight Review

Imalent just released the RT90 Luminus SBT-90.2 flashlight, and it’s quite a little beast!  It sports a “can-sized” body, a very throwy emitter, and good performance.  Read on for some testing and thoughts!

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Official Specs and Features of the Imalent RT90 Luminus SBT-90.2 flashlight

Here’s a link to the official product page.

Versions

There is just one version of the Imalent RT90 Luminus SBT-90.2 flashlight

Price

These are listed at $149.95, and as they’re very new, that’s probably about what you can expect to pay.

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Imalent RT90 Luminus SBT-90.2 Flashlight Short Review

This is a fun light.  While can lights aren’t necessarily lights that I chase or buy often, this is an unusually interesting one.  It’s small.  But it has a deep smooth reflector and has a ridiculous throw for a can light.  Performance is good (aside from missing the 4800-lumen claim at 30 seconds).

Long Review

The Big Table

Imalent RT90
Emitter:	Luminus SBT90.2
Price in USD at publication time:	$149.95
Cell:	Internal
Turbo Runtime	High Runtime
LVP?	Yes
Switch Type:	E-Switch
Quiescent Current (mA):	?
On-Board Charging?	Yes
Charge Port Type:	Proprietary Magnetic
Chargetime
Power off Charge Port
Claimed Lumens (lm)	4800
Measured Lumens (at 30s)	2709 (56.4% of claim)^
Candela per Lumen	79
Claimed Throw (m)	1308
Candela (Calculated) in cd (at 30s)	7270lux @ 5.693m = 235623cd
Throw (Calculated) (m)	970.8 (74.2% of claim)^
All my Imalent reviews!

^ Measurement disclaimer:  Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.

What’s Included

• Imalent RT90 Luminus SBT-90.2 flashlight
• Nylon pouch
• Charge cable (USB to proprietary magnetic)
• Spare o-rings (2)

I did not get a manual, but I have the pdf direct from Imalent – view it below.

Package and Manual

Build Quality and Disassembly

Again, this is a can style light, but overall such a very unusual implementation of it.  The build quality is good.  There are a few surprises, but not with how the quality of the build.

Here’s this emitter…. the Luminus SBT-90.2.  It’s an unusual choice for a can light, indeed!

And here’s the second unusual choice – the battery is built of four 18500 cells.  We’ve seen this setup before.  The Olight Olantern uses 4×18500.  This is neither good nor bad, of course.  Just unusual!  More on the battery pack later.

The body – or “cell tube” in this case – has ample but not aggressive knurling.

The bezel looks removable but I do not believe it is.  It’s a very nice bezel, too, with the crenelations that allow for light to escape when headstanding.

The body has an indicator light, which can be red or green.

Here’s that indicator lighting green.

Here’s a close-up of the knurling.  It’s a diamond pattern, and not terribly grippy.

The reflector is very smooth (and again, very deep!)

The switch is a little unusual.  More on it later.  It’s moderately easy to find without looking, and rotates freely in that opening!

Opposite the switch is the charge port.

A nylon pouch is included too.

The head and body separate easily.  The threads are surprisingly short on this light….  Unscrewing the head from the body takes approximately one turn, which is very unusual.  Conversely, that’s nice when putting the parts back together.  Also that the battery is built-in as it is, which makes screwing the parts back together very nicely.  You’re not required to fight against cells pushing against parts in the head.  All in all, this makes for a better experience.

Only the head has a spring, and it’s a big beefy one.  The body has to be screwed tightly enough to push the external ring of the cell holder against the ring of the head, but that doesn’t require too much effort.  The threads are smooth.

I found the threads to have a bit of excessive lube.  They’re short, anodized, and square-cut.

Also, you can note here where the replacement o-rings would go if you ever needed them.

Size and Comps

Product size: 65(head diameter)51(body diameter)127.5(length)mm

Net weight：428g(battery included)

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

Retention and Carry

The only way to carry the Imalent RT90 Luminus SBT-90.2 flashlight is an included nylon pouch.  The light must go in a “head up” orientation, and can’t be used while in the pouch.

Overall it’s a good pouch and fits the light very specifically.

Power and Runtime

As mentioned above, the Imalent RT90 Luminus SBT-90.2 flashlight is powered by a built-in 4×18500 battery pack.  I have not confirmed with Imalent if this is replaceable, but very likely these will be available for separate purchase.  The battery pack is apparently a 2s2p configuration because the fully charged voltage is around 8.35V.

This does mean that other similar Imalent lights that have the can-style body are absolutely not to be used with this battery body.  Those other bodies will definitely not work on this light either unless they provide >6V (and I don’t believe any at this time do that.)

I did not disassemble the battery, but I may yet.  I’m interested to see the cells used, and if they’re soldered in.  My guess is that they are soldered in place.

Here are a number of runtimes.  Turbo steps down quickly and dramatically but does hit the 4800-lumen claim at startup.  Around 1000 lumens for an hour isn’t bad, either.

High steps down too, but maintains just a little longer.  After the stepdown, the profile looks just the same.

In all tests, the light does shut off with low voltage protection.  There’s also an indicator warning of low voltage on the side of the light.  This sidelight turns red on low voltage.

On bench power testing, the RT90 indicating lights turned red at 6.5V, and at 5.5V everything shut off completely.

Also included on the RT90 is onboard charging.  This is by way of the standard Imalent charge port – USB to proprietary magnetic.  Despite being an 8.4V battery, the charging cable takes 5V input.  Ie there are no issues there.

The charge port on the light is two exposed metal dots.  The connection seems stronger than some early iterations of this connector.  It snaps into place very readily.

Here’s how the connector attaches.  The cord should go toward the tail of the light.

Charging is very good, at around 2A, or 10W for over 2 hours.  The total charge time is under 3 hours in all my testing.  And the final voltage is consistent at 8.35V, which is good for the cells.

Modes and Currents

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps at 8.4V
Turbo	4800/1350	70s/85m	2709	12.49
High	2800/1350	90s/93m	2709	7.50
Middle	1350	1h40m		2.14
Middle Low	350	2h40m		0.61
Low	10	90h		0.03

It’s just a completely random chance that both of the high outputs are 2709 at 30 seconds….  But I double-checked my data, and that’s accurate!  How random – last review a light was rated at 1100 lumens and was exactly 1100 lumens at 30s.  And now this.  Maybe this means things are lining up.  We’ll say that for 2021, ok?  2021 is looking good!

Pulse Width Modulation

Here you can see a “baseline” – a chart with almost no light hitting the sensor.

Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.

User Interface and Operation

There’s a single switch on the RT90.  It’s an e-switch, it’s on the head, and it has a plastic cover.  The action is very low but it clicks very positively.  The switch itself is not an indicating switch, but there’s a red/green indicator just near.

The switch sits almost flush with the surrounding body.  It is also directly opposite the charge port on the body, so just by feel it could be somewhat difficult to differentiate.

Here’s a UI table!  This user interface seems to be just like the Imalent MS06, which shares the style of the RT90.

State	Action	Result
Off	Click	On (Mode Memory (excluding Turbo/Strobe)
On	Click	Off
On	Hold	Mode cycle (10/350/1500/2800 order)
Any	Triple Click	Low
Turbo	Double Click	Strobe
Off	Hold	Iterate the indicator switch (on or off)
Off	Click 4x	Iterate Lock (indicated by 3x flashing of green indicating LED)

This is generally the same UI as the MS03, which I have also reviewed.

LED and Beam

The Imalent RT90 has a Luminus SBT-90.2 emitter.  This emitter is a real beast.

The emitter benefits from a smooth deep reflector.  Again, the reflector in this size light is a real standout.

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level and the beam hits the ceiling around 9 feet away.

Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.

I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!

Conclusion

What I like

• Very good thrower in a can style light
• Beam temperature is not unpleasant
• The user interface is good and consistent with other Imalents
• On-board charging is reliable at ~10W
• The proprietary magnetic charging is the Imalent standard.

What I don’t like

• The battery is built-in, and replacements are unclear
• Proprietary magnetic charging
• PWM on lower modes (but it’s fast and not really noticeable)
• Mode spacing between the two lowest modes is too broad

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Notes

• This light was provided by Imalent for review. I was not paid to write this review.
• This content originally appeared at zeroair.org.  Please visit there for the best experience!
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