Jetbeam SF-R28 XHP-50 1,600 ANSI Lumens on 1X 18650 Video Review

Jetbeam has a new 1X 18650 XHP-50 light out that goes by SF-R28. The SF-R28 has a boost driver to give it's XHP-50 6V off a single 3.7 18650. This light was provided to me by Andrew-Amanda.com for review on YouTube.

The highlights of the SF-R28 are it's output for its size, given it's a single 18650 light. SF-R28 also has a fair measure of throw given that it uses a smaller XHP-50 vs the XHP-70. I also personally like the semi-tactical design with the forward clicking tail-switch. Though the side e-switch for mode switching, is less tactical in nature, it also can make easier mode switching for walks, or any activities if holding the light in the hand for an extended period.

Only ANSI FL1 spec for the following: With my light-box calibrated to give exactly 960 lumens off of the Nitecore SRT7 Revenger using a fully charged high drain 30Q cell, I got 1640 lumens as a result for the new SF-R28 regardless if using IMR or ICR type batteries. I'll just call it 1,600 lumens.

The SF-R28 sustains 1,600 lumens for 1 min. 30 sec. before it will begin to ease down over a period of 45 seconds when it then maintains 850 lumens indefinitely. The light will always go back to it's full 1,600 lumens when clicked off and back on or when cycled through. Also double clicking the e-switch on the side will go straight back to turbo 1,600 lumens without shutting off the light.

SF-R28 does very well with thermal management. 1,600 lumens turbo is prime real estate for a light like this to be used in turbo for extended periods. After 5 minutes of sustained turbo the light was pretty warm but in no way uncomfortable, and not quite what I would call hot yet, for a very unscientific analysis. The light also cools quickly when turned off or switched to lower modes.

At about 3.6V the light cuts out high and turbo modes and only functions in mid and low modes. This basically says that it is time to recharge the light even though it can actually continue for another hour or so in it's 150 lumen low mode. It seemed premature to cut out turbo at 3.6V. However, the light is designed to be optimal for both standard lithium cells as well as high drain, and function the same regardless, so I understand the thinking behind designing the light this way.

The built in charging although better than nothing, only charged up to 4.05V which is sub-par. Charging is 750MA. Given that turbo cuts out at 3.55-3.6V I would have really liked to see a full 4.2V off built in charging. EDIT: If you click the rear switch on when you plug in the USB charger, the light will charge to 4.2V with a good CC/CV rhythm. However, the charge indicator light won't function properly when doing this do just give it a good 4 hours when empty and it will do the rest.

I like the SF-R28 for its size, brightness and it's ease of use. Almost perfect for night walks or even some patrol applications. Glad it has built in USB charging but really wish this was implemented better. My video review is as follows...

Thank you for the review/video!

It does has decent throw. What is the cd rating on turbo?

I hope your vertigo has resolved too. Happy New year!

Jetbeam SF-R28 has a rating for 1500lumens right? Btw. In turbo mode. How much amp does it uses at max? Thx

so if i use a 10 A high drain 18650. it will be enough to drive the turbo mode without going down to 8xx lumens right?? or is it timed? can i go to set turbo mode for as long as i like or until the thermal throttles it?

also.. if i use like standard 18650 ( like only 2A max burst for example ) even if i charge the batt fully, i wouldnt be able to go to turbo mode right? i mean if the amp is not enough , will the turbo and or high mode just blocked? so i only have low and medium? thanks btw

Mine had a fairly definable black spot in the middle.....biggest I have ever seen on any of my flashlights. I thought it would disappear at distance but outside I could make it out at the end of my property. I wasn't aware that it could be a XHP-50 commonality and just assumed that the reflector wasn't at the right distance from the LED. The only other XHP-50 LED light I have is the Fenix TK35UE and it does not have a black hole at all. It kind of bugged me and I returned it.

Also, not sure I liked the really soft mode switch. I prefer a little more tactile. I really wanted to like the light but knew that black hole was going to bug me.

hiuintahs said:

Mine had a fairly definable black spot in the middle.....biggest I have ever seen on any of my flashlights. I thought it would disappear at distance but outside I could make it out at the end of my property. I wasn't aware that it could be a XHP-50 commonality and just assumed that the reflector wasn't at the right distance from the LED. The only other XHP-50 LED light I have is the Fenix TK35UE and it does not have a black hole at all. It kind of bugged me and I returned it.

Also, not sure I liked the really soft mode switch. I prefer a little more tactile. I really wanted to like the light but knew that black hole was going to bug me.

Click to expand...

Do you think that you got a defective unit? as the video did not show any black spot in the middle of the beam? btw can you tell me the specification of the battery u are using on the flashlight? it would help me alot. thanks

carl said:

Thank you for the review/video!

It does has decent throw. What is the cd rating on turbo?

I hope your vertigo has resolved too. Happy New year!

Click to expand...

I got 17680 lux when calculating from 2 meters. This equates 266 meters throw. The stuff from my neurologist seems to be resolving it. Pretty sure it's just a matter of time now. Thanks, Happy New Year.

White7561 said:

so if i use a 10 A high drain 18650. it will be enough to drive the turbo mode without going down to 8xx lumens right?? or is it timed? can i go to set turbo mode for as long as i like or until the thermal throttles it?

also.. if i use like standard 18650 ( like only 2A max burst for example ) even if i charge the batt fully, i wouldnt be able to go to turbo mode right? i mean if the amp is not enough , will the turbo and or high mode just blocked? so i only have low and medium? thanks btw

Click to expand...

Absolutely high drains are not required for this light. Turbo is timed always for 1:30. Double click the side switch will reset turbo without shutting off or cycling through modes. I'm not sure exactly max burst, but I used some laptop pulls and it still went into turbo and tested 1,600 lumens just fine.

hiuintahs said:

Mine had a fairly definable black spot in the middle.....biggest I have ever seen on any of my flashlights. I thought it would disappear at distance but outside I could make it out at the end of my property. I wasn't aware that it could be a XHP-50 commonality and just assumed that the reflector wasn't at the right distance from the LED. The only other XHP-50 LED light I have is the Fenix TK35UE and it does not have a black hole at all. It kind of bugged me and I returned it.

Also, not sure I liked the really soft mode switch. I prefer a little more tactile. I really wanted to like the light but knew that black hole was going to bug me.

Click to expand...

Yes, it is a bit more than some other xhp-50 lights. Maybe even a little more than the Nitecore EC4S. I notice it indoors but outdoor I don't really notice it at all. Yeah, I think it may definitely bug some people more than others. Maybe Jetbeam made the reflector a bit too deep and not enough wide in order to increase throw and maintain a small profile.

I had pretty high hopes for this light too and as it stands I still like it. However, I am definitely not as enthused as I thought I would be. Still like it for nighttime walks at the 400 lumens setting and double click goes to turbo. One more click cycles back to 400 lumens so it works well that way.

Impossible lumens said:

It's harder to see it in the video but it is there. I think that the little spot just bugs some more than others and that there may also be slight variations between samples.
I used Samsung 30Q 3,000MAh with max continuous draw of 15A. I don't see any difference between using any high drains vs something like a non high drain 18650B. Forgot to mention that it takes button tops only though. I was using a little neodymium magnet on the positive end. I'll go add annotations to the video now.

Click to expand...

okay , so both batteries will work fine thanks.. and now last question. i saw on the web there is 5 modes.. some say 4. is there 4 or 5? (4 without moonlight)

White7561 said:

Do you think that you got a defective unit? as the video did not show any black spot in the middle of the beam? btw can you tell me the specification of the battery u are using on the flashlight? it would help me alot. thanks

Click to expand...

It's harder to see it in the video but it is there. I think that the little spot just bugs some more than others and that there may also be slight variations between samples.
I used Samsung 30Q 3,000MAh with max continuous draw of 15A. I don't see any difference between using any high drains vs something like a non high drain 18650B. Forgot to mention that it takes button tops only though. I was using a little neodymium magnet on the positive end. I'll go add annotations to the video now.

Wait. 750mA charging via usb? That means about 4hours++ charging time?? Btw. What is the lowest cost flashlight with 2000lumen or up? Thank you for your time reviewing this flashlight btw.. And i am "Matthew" from the youtube video comments section (Jetbeam SF-R28)

Impossible lumens said:

At about 3.6V the light cuts out high and turbo modes and only functions in mid and low modes. This basically says that it is time to recharge the light even though it can actually continue for another hour or so in it's 150 lumen low mode. It seemed premature to cut out turbo at 3.6V. However, the light is designed to be optimal for both standard lithium cells as well as high drain, and function the same regardless, so I understand the thinking behind designing the light this way.

The built in charging although better than nothing, only charged up to 4.05V which is sub-par. Charging is 750MA. Given that turbo cuts out at 3.55-3.6V I would have really liked to see a full 4.2V off built in charging.

Click to expand...

Hey i have maybe a good news? so here... Jetbeam SF-R28 didnt allow us to charge using more amps than 750 amp and didnt allow us to go to 4.20 volt right? i might found a bug that maybe will give us what we want.. faster charging with more fuller battery.. so heres what you gonna do

first charge the battery fully (to 4.05 V) using the flashlight itself.. but use the usb current meter thinggy ( the one u can see amp and volt when using usb ) and ( until the blue light is off )
then , without pulling the power ... see that the meter should read about 5 volt and the amps gonna go as low as 0 - 0.5 amps ...
Now, when this happens. turn on the flashlight while charging... the light will not on (the XHP50 LED) and the blue charging light will turn on again right? now see the meter.. the amps should be increasing to about 1 A -1.2 A... now if we just let this sit until the battery become full, the internal battery PCB must stop charging when its on 4.2 volt true? ( because we use pin top protected battery )

if this is working... we might have a workaround to getting this flashlight to charge to 4.2Volt and charge faster...

FYI : Sorry if my English is not good ... English is not my main language
and
PS : I actually have not tried this yet. because im not at home but earlier today when im trying to charge my flashlight and using the meter, i noticed the amps getting to about 1A when i charge and turn on the flashlight... i did not let it to go charge like that when im not home... because i dont know if the pcb will stop charging if the battery is already full...


Hope this can be useful

I went right to 16 minutes to see the outside beams video. Looks bright. Thumbs up on the video and subbed your channel.

White7561 said:

Wait. 750mA charging via usb? That means about 4hours++ charging time?? Btw. What is the lowest cost flashlight with 2000lumen or up? Thank you for your time reviewing this flashlight btw.. And i am "Matthew" from the youtube video comments section (Jetbeam SF-R28)

Click to expand...

Hey there White7561. Yes, I remember your comments from YouTube. Welcome to CPF. I think that for this particular light you'd likely begin charging at 3.5 or so volts which is where turbo and high mode cuts out. From there to the 4.05V that built in charging has been doing might be less time since we're not talking about the batteries full capacity.

I'm running a test now on the behavior you discovered with this charger. It does kick back on if you turn the tale switch on. I'm watching it closely with an unprotected cell. If it goes to about 4.2 and cuts out on a CV charge then that's wonderful. If it tries to keep feeding the cell 5V indefinitely then I might be calling Jetbeam because this is a real safety issue. First the Note 7 and now the SF-R28, not on my watch. LOL

Back in a jiffy with some results. Again, the manual mentions nothing about this.

Woods Walker said:

I went right to 16 minutes to see the outside beams video. Looks bright. Thumbs up on the video and subbed your channel.

Click to expand...

Thanks very much. I try to get a few decent beam shots in there. All that technical esthetic stuff doesn't mean much if the beam doesn't impress for your particular usage.

Impossible lumens said:

Hey there White7561. Yes, I remember your comments from YouTube. Welcome to CPF. I think that for this particular light you'd likely begin charging at 3.5 or so volts which is where turbo and high mode cuts out. From there to the 4.05V that built in charging has been doing might be less time since we're not talking about the batteries full capacity.

I'm running a test now on the behavior you discovered with this charger. It does kick back on if you turn the tale switch on. I'm watching it closely with an unprotected cell. If it goes to about 4.2 and cuts out on a CV charge then that's wonderful. If it tries to keep feeding the cell 5V indefinitely then I might be calling Jetbeam because this is a real safety issue. First the Note 7 and now the SF-R28, not on my watch. LOL

Back in a jiffy with some results. Again, the manual mentions nothing about this.

Click to expand...

Yeah. but if it didnt stop feeding 5v to the battery.. will it be kinda fine then? to us that use protected battery? as the battery already stop the charging from happening when on 4.2volt ?

edited : Please share your findings if you find anything new... thanks im gonna go sleep now cause its 3.21AM here Thanks

White7561 said:

Yeah. but if it didnt stop feeding 5v to the battery.. will it be kinda fine then? to us that use protected battery? as the battery already stop the charging from happening when on 4.2volt ?

edited : Please share your findings if you find anything new... thanks im gonna go sleep now cause its 3.21AM here Thanks

Click to expand...

I think it will be ok actually. It's slowing down the amps as gets towards 4.2 I'm pulling to test V every 10 minutes. I don't think you'll need protected cells for this charger and maybe still get close to 4.2V. For me, I have to click the tail switch when on the USB for it to start feeding higher amperage. I'm actually charging another cell because I took the first one out to test it and it was 4.18 which is good. but it was still feeding .2A when I pulled it and wouldn't begin charging when I replaced it. I think it won't begin a charge if the V is already at a certain point, but if it is finishing off a charge then it might just hit 4.2. Looks like good news and that clicking the tail while charging is the key to SF-R28 built in charging. This is great. Thank you so much for sharing this finding as I was completely oblivious. I've never heard of clicking on the tail while USB charging so don't know if it is something already commonplace for lights with this configuration or not. Yeah, get some sleep. I'll post the final result soon.

White7561 said:

Hey i have maybe a good news? so here... Jetbeam SF-R28 didnt allow us to charge using more amps than 750 amp and didnt allow us to go to 4.20 volt right? i might found a bug that maybe will give us what we want.. faster charging with more fuller battery.. so heres what you gonna do

first charge the battery fully (to 4.05 V) using the flashlight itself.. but use the usb current meter thinggy ( the one u can see amp and volt when using usb ) and ( until the blue light is off )
then , without pulling the power ... see that the meter should read about 5 volt and the amps gonna go as low as 0 - 0.5 amps ...
Now, when this happens. turn on the flashlight while charging... the light will not on (the XHP50 LED) and the blue charging light will turn on again right? now see the meter.. the amps should be increasing to about 1 A -1.2 A... now if we just let this sit until the battery become full, the internal battery PCB must stop charging when its on 4.2 volt true? ( because we use pin top protected battery )

if this is working... we might have a workaround to getting this flashlight to charge to 4.2Volt and charge faster...

FYI : Sorry if my English is not good ... English is not my main language
and
PS : I actually have not tried this yet. because im not at home but earlier today when im trying to charge my flashlight and using the meter, i noticed the amps getting to about 1A when i charge and turn on the flashlight... i did not let it to go charge like that when im not home... because i dont know if the pcb will stop charging if the battery is already full...


Hope this can be useful

Click to expand...

Your English is good. So I tested this several times today and what I did was simply turn on the tail switch after I plug in the charger. Charged my non-protected 18650GA until my amp reader showed 0.00 amps. Pulled my 18650GA and tested at 4.2V. This is perfect as far as I'm concerned. Did this a few times beginning from 3.5V, 3.8v, 4.0V and got the same result using a different type non-protected cell each time. That's much better than 4.05 for sure. The manual doesn't mention anything at all about clicking the light on after plugging in the charger but it seems to work just fine. Maybe it just needed proper contact. Power to the LED is cut when charger plugged in so I don't see it hurting anything. I did unclick it before pulling the USB plug as it is a little unnerving when the light comes on in turbo when unplugging the USB.

Impossible lumens said:

Your English is good. So I tested this several times today and what I did was simply turn on the tail switch after I plug in the charger. Charged my non-protected 18650GA until my amp reader showed 0.00 amps. Pulled my 18650GA and tested at 4.2V. This is perfect as far as I'm concerned. Did this a few times beginning from 3.5V, 3.8v, 4.0V and got the same result using a different type non-protected cell each time. That's much better than 4.05 for sure. The manual doesn't mention anything at all about clicking the light on after plugging in the charger but it seems to work just fine. Maybe it just needed proper contact. Power to the LED is cut when charger plugged in so I don't see it hurting anything. I did unclick it before pulling the USB plug as it is a little unnerving when the light comes on in turbo when unplugging the USB.

Click to expand...

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