*BLF LT1 Lantern Project) (updated Nov,17,2020)

no way i can imagine a boost circuit to make the 2.9-4.2V cells deliver 12V would make sense and probably is very expensive
Lets forget about anything other then 5V USB out please.

Definitely agree there. Its just not practical or a good idea at all to put a 12 volt output on a small lantern, especially one that has to be compact as a beer can and have long run times from 4 - 18650 cells in parallel.
a 5 volt USB charging cirsuit is possible, but a 12 volt out, no.

Many power banks have cells in parallel with QC USB output at 12V. Let alone all the single 18650 XHP35 lights.

And all those XHP35 drivers out there?
A single boost driver could deliver 6(?)V to the LEDs, 5V to the USB output and 12V to the 12V output. It would possibly be somewhat more expensive than linear + small boost, but would deliver better efficiency, higher 5V power and 12V (with slightly worse efficiency) on top of that.

[quote=sac02]

Is it really? There are plenty of 12V->USB converters out there…

Great, thanks! (nobody has understanding for the decision of pb anyway)

[quote=Agro]

This is true
And would mean a port less, less electronics so yeah valid IMHO but it is up to DBSAR of course.

[quote=The Miller]

To keep the cost, size, and complexity of the lantern to what is practical, no 12 volt output is planned. This is to be a “lantern” that is meant to do what a lantern is supposed to do. :slight_smile:
(I use a portable 20 AH LiIon booster unit i bought from Interstate for when i need a portable 12 volt output on wilderness or camping trips.

HI,

ive been watching this project off and on for a long time now,

I have a couple of suggestions for you , feel free to totally ignore them as they are only a couple of ideas from a distant admirer,

1, if you are going to put a USB power out on the lantern then please make it a USB-c compatible output.

yes i know this is not a simple circuit but it means it is 100% upto date and would make it last a lot longer as a design.
it would allow fast charge (2-3 amps from memory) both in and out with the right components.

2. is there a reason you dont just use the led’s on the torch side with a reflector on the top not the bottom and then just turn the torch upside down? it would mean you are just adding a reflector to the top instead of trying to mount the led’s up on top.

anyway , feel free to ignore

Scorpia

Physically it’s a good choice. But supporting USB 3.1 by protocol would make the project to expensive.
Also the 2.4A usable without USB3.1 are indeed quite a bunch of power (15W). More than enough to charge 1-4x 18650 cells with up to 1A and powering the lantern simultaneously.

Talk is being done
While there are very cheap chips to be found it is a tell tale sign Xiaomi is using a Ti chip in its powerbanks.
I asked the USB C question in the PM DBSAR, DEL and TK are having aboit the driver. But as always costs are an important factor and with all the mUSB hardware it is long from dead and loads if adapters can be found and surely will be able to be bought for many many years to come.

yes i understand cost is an issue not sure how much of an issue,

as for the usb-c connector it has one big advantage if done properly. 1 connector for charging and discharging.

also you wouldn’t need to support usb 3.1standard as this is a power back, im pretty sure there is a different standard for power delivery.

Either way, people are looking at the idea so it cant be all bad,

I have been playing with my Q8 with lantern attachment for a while and I noticed that the Q8 is pretty heavy for a lantern. And then I realised that this weight is not at all needed for a lantern: apart from the batteries the lamp may weigh next to nothing because the maximum power used will just be around 3W, so heat-path and -sinking is as good as irrelevant. A bit counter-intuitive for BLF, but I vote for a (sturdy enough for abuse but) lightweight design.

I definitely agree. If BLF is going to take on this project, I’d much rather see an original lantern design that strives to push the design of LED lanterns forward rather than a diffuser-like attachment or a design based off a flashlight that was never intended as a lantern. That said, I do like the size and form-factor of DBSAR’s prototype.

So it will feature 300lm?
Seems a bit low i believe.

I got the 3W from DBSAR’s discussion with sac02:

But even with 2A a really lightweight build is sufficient.

Three 7135’s provide more than enough light for this type of application. My similar in concept 4th annual contest entry, the mug-o-light, has three and I never run it on high. I understand why DBSAR reduced it to 2.

I think we talk 700-1000mA (3 * 7135 max)

The integrated shelf of the Q8 is not needed, a small flat area above the tripod mount for the USB connectors (well that is going with my idea of using the tripod mount to secure a rubber flap to ensure water proofing which seems logical to me)

Above that the diffuser and wires holding poles
So I expect the lantern to be lighter but some weight helps inbsturdy placement so is not bad.

Unfortunately, weight=good at BLF, while when I go out camping reducing weight is all-dominating!!! If I want a firm base I rather make the base wider instead of the light heavier.

Well true, but I don’t see a lot of fat on Q8 tube, tail and lower part head so removing the integrated shelf that is not needed and a good diffusing downwards facing led part seems the lightest 4 18650 config without going titanium
Seeing the HJK thermal images if powerbanks makes me think the few fins remaining on the head do have a function.

We are talking 172gr of cells

Plastic lanterns are plenty but come on, it only needs one time placing the backpack down wrong to render them useless.