Their history doesn’t matter because they’re not in series. There’s no balance between the cells that you have to maintain. Fully charge them all before putting them in the LT1 and it’ll be fine.
Yep exactly, you could even use some 1200mah, 2000mah, 3000mah and 3500mah batteries mixed together, as long as they are the same voltage when you start, they will act a giant 9700mah battery, no problems. That becomes less true when there’s more current being drawn, but for this light it’s perfectly fine.
Normally it’s amber/orange but when charging it’s red and when charged it’s green.
See the “production model” video at roughly 6:30
By default it should go up to about 600 lumens. Maybe 800 if you connect the extra 7135 chips by soldering some pads on the battery side of the driver. At the low end, it goes down to about half a lumen. In-between, it can do whatever you want, since it has 150 brightness steps and 254 tint blends (plus two “auto” tints).
Also by default, it uses a 5-step ramp instead of a smooth ramp. I think the lowest step is about 10 lumens and the top is full power (~600 lm). But this is configurable.
Runtime at the highest level is about 6.8 hours with 3000 mAh cells or 8 hours with 3500 mAh cells. At lower levels, it’s much much longer, like close to a year on the lowest level.
For battery type, any married set of 4 identical button-top cells should work. If you already have some available, use them. If not, get a new set. Sofirn’s cells are 3200 mAh and pretty decent, especially for the price. But I used a set of old LG cells I had in my Q8, which were originally purchased to go with a Meteor.
People usually just put a diffuser cap on their favorite 1x18650 flashlight. It helps if the light has a side switch so it can be operated while tail-standing or hanging on a lanyard, but that’s not a difficult requirement.
The control chip can only access the amber LED. It can be dim, bright, or off. During use, it mirrors what the main LEDs are doing, and while the main LEDs are off it can be configured as off, low, high, or blinking.
The charging circuit is completely independent, and controls red + green LEDs. They are only used while the lantern is plugged in.
So the firmware cannot change the color of the button. It’s not even physically connected to the red+green LEDs.
About inserting the batteries the right way and fire hazards, the LT1 has the exact same design and traits as most soda-can-style lights like the BLF Q8, the Noctigon Meteor, the Sofirn SP36, the Skyray King, the Emisar D18, the Blackshadow Terminator, and the ROT66v2. Basically, anything which uses a shared contact ring for multiple batteries.
To use it as intended: Use button-top cells, keep their voltage the same, and insert them all with + facing toward the contact ring (and - facing toward the springs). The presence of a single shared contact surface should be a big clue that all the batteries must go the same direction.
If some of the batteries are inserted backward, the wrong-way ones shouldn’t make contact because the cell wrapper is in the way. However, it can make contact anyway. This happened when my mother tried to put batteries into a SRK. When that happens, the result is two dead springs. The springs act as fuses to prevent any worse issues from happening.
If cells of very different voltages are inserted, the result is pretty much the same as if some cells are backward — rapid equalization until the springs melt. Depending on the cells used, this could also damage the cells.
If all four cells are backward, it shouldn’t do anything bad. If I recall correctly, the driver has electrical reverse polarity protection so it simply doesn’t turn on.
To fix these issues, it would need to either get rid of the contact ring design entirely or add some plastic spacers which physically prevent flat cells from making contact.
I was already down for 1, but in case there are individual codes I would like to add +2. I’m very excited for this launch.
I’d like one more, for a total of 3.
Hi all. I’ve followed this project since the first post and what a marathon effort it has been. This really is looking to be a fantastic lantern and kudos to all involved.
Pretty late in the process to be asking this, but from recent posts I understand the USB-C input connector is not potted? IPX rating is only met if the charging socket is covered with the rubber plug. IIRC, Den mentions this in either a thread comment of one of his video reviews. I think he said it would be OK in the rain but not submersible.
I am highly interested in using this lantern with a solar panel. The issue for me is that I will sometimes be using the rig on long canoe trips and wondered what would happen in the event of a capsize if I was charging while paddling during the day. (No comments about it sinking to the bottom please!)
I guess it boils down to:
1. How much additional effort would be involved to have the socket potted at the factory?
2. If the factory option is not possible, is this a mod that I could make relatively easily?
3. If the worst does happen and I get water ingress, what would be the likely effect? Fried driver?
Once again, thanks to all concerned.
1. Not much actually. Just more expensive, and a lot more time to manufacturer.
2. Yes. Just put some RTV silicone around the USB-C internal hole.
3. Well, that depends if the batteries get submerged. The electronics themselves would likely been fine, but once the cells get submerged, they will rust away.
I would like one!
Thanks BlueSwordM
Maybe an obvious question but the RTV silicone option you mention - are you talking about opening the light to apply it or just using a fine needle to put some in the base of the socket from the outside?
Batteries I can replace easily if the worst happens but the lantern I cannot.
Cheers
Opening the light itself to apply it obviously.
Just put it around the USB port.
It should actually be pretty easy to open the light via the driver, as it is necessary to do to mod the driver and perhaps other components, since it’s based on the BLF Q8.
Add me please!
+1. It’s unlikely that an experienced backpacker do multi-day hiking with this lantern in tow.
I would consider carrying it into the woods for a single overnight if I was with a large group and we were simply hiking back out the next day, but even then I’d have to leave something else behind. You can afford such sacrifices on an overnight jaunt or party, but not for multi-day hikes.
Non-backpackers should not buy backpackers gifts unless they already know some specific items that the person wants or needs (this is a good use for a public Amazon wish list, btw). Car-camping is very different than backpacking, especially long-distance backpacking.
Pretty much the only car-camping items that I own are things that people gave me as gifts and I then had to be gracious about receiving stuff that was useless to me 
.
Let’s put it this way; most people understand that they shouldn’t gift a very nice-looking backpack to a skydiver and the same concept applies to backpacking, mountain climbing, or deep-sea fishing 
. Unless you also do those things, then you probably don’t know which stuff to buy.
Still, backpackers may sometimes use car-camping equipment near trail-heads before or after being in the woods for a week, so the LT1 may still be appreciated in those situations. An LT1 is likely most useful for people in their homes and apartments, so it should be an appreciated gift whether the recipient hikes, kayaks, or simply collects human heads. Just don’t suggest that the LT1 is for backpacking the AT 
.
Thanks.
It’s a little hard for me to visualize from drawings. Still waiting for the inevitable “tear down” video.
I’m almost embarrassed to admit it here but somehow I never got around to getting the BLF Q8 - a bit of an omission on my part! :person_facepalming:
@gadabout, since you’ll open the light, why not waterproof the components?
For waterproofing the USB port: https://www.amazon.ca/Red-Devil-0795-StormGuard-Silicone/dp/B071F9W84K/
For waterproofing the driver itself, you would need some sort of thermal epoxy, or something like conformal coating!
@BlueSwordM thanks for that info.
I’ll look into these; the Conformal seems particularly useful.
On advice from a thread here, I remember coating some small usb touch lights with clear nail varnish a couple of years ago and they are still going strong.
I’m interested, please put me down on the list. Thanks.
I tried really but did not find the youtube video anywhere. Any links to it? Cheers