BLF LT1 Runtime test *updated 12/11 with step level 2*

Update 12/19/19 - I added my full review of the LT1 lantern here: https://greencampfire.com/blf-lt1-lantern-review/

Hello all,

I received my LT1 lantern and was eager to test out the runtime of the lantern on high. I plan to write a full review on the lantern (spoiler, I think it’s the best consumer lantern out there right now) as well as many other lanterns under this new handle, but for now here is the runtime chart. As you can see, the lantern stepped down as the manual says it will as the voltage drops. I stopped the runtime test at the 400 minute mark since I didn’t want the voltage of the batteries to get too low. The ending voltage was 2.9V for each cell. I’m using the 3000 mAh Sofrin batteries that came with the lantern as part of the GB.

As you can see the LT1 can sustain output on it’s highest mode for almost 5 hours straight. What other lantern can do that? Very impressive.

Update 11/28/19

I reran the runtime test on high after resetting the firmware to so I could test with the default tint. The runtime is very similar to what I previously tested.

I also did a runtime test on step level 4. The output should be around 342 lumens. Over 8 hours of sustained output.

Update 12/5/19

Here’s a runtime test on step level 3 with the default tint. The output should be around 162 lumens. Over 16 hours of sustained output.

Update 12/11/19

I updated the charts above for step levels 4 and 3 to more accurately reflect what the relative lumens output is at each step. The steps levels is not a linear progression, for example, step 4 is not 80% of max, step 3 is not 60% of max, etc. This is done intentionally since our eye wouldn’t perceive the change in output as linear even if it was.

Here is also the runtime test for step level 2. The output should be around 48 lumens. Over 62 hours of sustained output.

1 Thank

Awesome, thanks for publishing this data. Based on the lumen output measured I’m guessing you have used the lantern as is, that is only 5 of the seven output drivers are enabled? On my lantern high is 1.85A, which would result in about 6.5 hours of runtime for a 3000 mAhr battery. It seems like you didn’t get as long as I would have guessed, much closer to having all 7 output driver channels enabled.

I just noticed this is your first post, welcome to BLF! :beer:

That’s correct, I’m using the lantern as is. I don’t have a way of measuring lumens only relative output so the immediate light output measurement when the lantern is turned on in high mode is what I use as the baseline of 600 lumens in the chart.

Welcome to BLF GreenCampfire! How nice of you to enter with a useful graph :-).

I’m curious how you do the lumenmeasurements?

Edit: just explained :slight_smile:

What’s the best way to measure the amp draw on the LT1?

remove the base, connect one of the driver mounting screws to the non anodize part of the base, put a DVM set to measure current between the battery ring and one of the cells in the base.

I guess I got a better connection this time and got 1.9A.

On high I measure 2.4A but I didn’t enable the other output drivers. I reset the firmware so the tint is the default. Why would this be?

Hard to tell from the image but NW 6&7 might be bridged. Some of the early LT’s were incorrectly soldered so all 7 7135’s were enabled. If they are soldered check with your DMM to see if they are bridged or not.

Sorry I’m a bit inexperienced with this. What connections do I make to test if they are bridged?

Switch to the ohms (resistance) on the dial. Get the leads to touch each side of the 6/7 pads. If it’s low then they might be bridge, if it’s fairly high or out of range then they’re not bridged.

Exactly what I am looking for!

Any plans on doing a runtime on 3rd and 4th mode? I use those more than I do 5th (highest mode).

Yes! I’m going to first figure out if the other output drivers are enabled for my lantern then will do more runtime tests for the default levels in step mode.

We might be able to tell if you post a close-up pic of the driver.

BTW, GreenCampfire your method of measuring current is much better than mine . . . :person_facepalming:

No need for the clip lead that keeps coming off, or to try to clip to the battery holder.

Almost 5 hours!? Wow! Thanks for the testing and welcome to BLF! :person_with_crown: :+1:

Well I did another test of my LT1, using the current measuring method of GreenCampfire above. With 5 channels enabled, I measure 2.2 A on my meter with neutral tint mixing (factory reset) using a 30Q, and 1.6A using a sofirn 2200mAhr battery. Both are button tops. Interesting the Sofirn cell is not really delivering. With my laptop pull cell I get 2.06A. The sofirn cell is near 3.6V, The 30Q is at 3.8V, and the laptop at 3.9V. Guessing that cell impedance somehow factors into current draw, even with the 7135s limiting the current? I don’t really get it, unless the voltage is drooping enough that the 7135s are not really limiting the laptop pull and Sofirn cell.

More experiments to follow, including a run test with 4 ~3000mAhr cells I have that I’m topping off right now.

I get a reading so it looks like my 6/7 pads are bridged then?

Check left half moon of 6 and right half moon of 6. I’m too lazy to open paint and make a picture. Then repeat for 7. Sorry was not clear earlier. But from that close up picture does not look like they are bridged together, so you should get a pretty high reading.

I would expect that one side of pad 6 and one side of pad 7 would be connected. What was suggested (not clearly enough) is to measure the resistance between the two adjacent pads labeled 6, the two adjacent pads labeled 7, for both WW and NW. Zooming in on the picture, I would think they are not shorted together.

The recent measurements I made suggest that the pads are not connected, but somehow there is more current demand from the batteries than expected. I made some measurements in my previous post with a few different cells. I with my 30Q cells, I got numbers close to you. with other cells the readings were a bit lower.

I meant to change the tint to all one or the other direction, will check that out when I pause my current run test later this evening. The current changing with tint was an observation made in the early versions of tint mixing firmware, but I thought that had been addressed.

Welcome to BLF GreenCampfire! Awesome test with graph too :+1: :smiley: That is about what i got on the production model with the 3000mah cells running it on maximum is between the 5 to 5.5 hours non stop. I usually run it on a mode or two down, (75 to 80%) and seems to nearly triple the run times, but i don’t remember if it was on the 3000 mAh , 3200mAh or 3500 mAh cells i was testing at the tome for that lower mode running.