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

I’ve heard that people occasionally put batteries in backward. I don’t really understand it, but I guess it happens sometimes. Fortunately, the Q8 already has a way to deal with potentially-hazardous situations. When a cell was inserted backward, the springs worked exactly as designed and acted as a fuse to prevent any serious issues.

Maybe a thin plastic ring could be added for additional protection. Maybe not. Not sure if it’ll be a feasible option. One was part of the Q8 design for a while, but then it didn’t happen. It’d be nice, but not having it isn’t a huge loss.

I think it could work.

Not a huge loss on a lantern, unless you actually were relying on it to be a lantern, for light, in the outdoors, and to “just work”, with maybe little or no backup. Rather than a plaything. Better carry a few candles too.

Could be quite a big loss, if the springs are bypassed on a tuned-up Q8. We haven’t seen that, yet.

Surely this is a fundamental for any lantern to be taken seriously, i.e. ruggedness, reliability and fool-proofness, in all hands, young to old, not necessarily indoctrinated in arcane LiIOn procedures. I’m not sure I am hearing this loud and clear.

Just a worrier, who sometimes doesn’t get cells in the right way around, an imperfect human.

It has already been warned of the risks of placing an inverted battery

A worrier paints a vivid picture which sticks easily in the minds of people who see it, often overriding a more accurate map of reality in which the meaningful risks lie elsewhere. People spend inordinate amounts of time and effort worrying about one-in-a-million risks while ignoring things which are actually likely to happen. This has a cost, and can be contagious. On an individual basis it’s a relatively small opportunity cost, but when repeated on a larger societal scale it has bigger and more meaningful consequences. So I try not to encourage people to focus on unlikely risks.

Several companies have been using the contact-ring design for several years with a near-zero rate of incidents, so I expect the risks involved are very small. This is probably because it’s common knowledge that batteries have a right way and a wrong way; it is not an arcane or chemistry-specific procedure.

If you know you are personally at a high risk though, it’s fairly easy to prevent issues by applying a bit of non-conductive tape or shrink wrap. For example, a bit of tape over the outer edge of the contact ring, or an extra layer of tape or wrap on the batteries to recess the negative pole. I’ve done something like this with good results — my bench power supply is on a wire shelf so I wrapped nearby surfaces with kapton tape to avoid accidental shorts where I do electrical testing. And, after burning myself one day during a test, I make sure my clip leads are shrouded.

Anyway, if it’s feasible to do so, I’d like to add a plastic layer on the edges of the contact ring to improve fool-proofness. Even a small risk is worth avoiding if there is no significant cost in doing so. But given how rarely it has been an issue in past products, I don’t think it’d be a big problem if it didn’t happen. Other design details have a higher priority.

Then we are agreed. By the way, the Q8 brass ring is different, it is small in diameter, and only just meets the centre of the cell buttons, so they have a natural tendency to tilt when put in the wrong way around, so are more likely to make contact when reversed.

Traditional SRKs with no brass ring, just a flat driver surface, or other designs with brass rings that have better contact with the buttons, are less susceptible. For these, decent wrappers on the negative of the cells are probably enough to prevent contact when reversed.

Not necessarily so on the Q8, and it cannot be denied that it has happened, at least twice, and I am sure will again.

I agree This is important.
But also needs to be water proof , I know I sometimes get caught in the rain camping

I will be performing some tests eventually soon (if the weather don’t get to bad when i get it ready to test) (outdoors under controlled conditions of exactly those scenarios. ( 1 cell in reverse against the other three and full connection made. ) and other tests like a depleted cell thrown in the 4-paralell config with three fully charged. ( if any cells survive the first tests) I will build a jig to hold the cells with 10-gauge solid copper wire 8 feet to a 50 amp switch)

a good water “resistant” to rain and splashing is easily possible, but make this “waterproof” as to an IPX standard will drive costs up not completely necessary to have it reach an IPX7 or 8 level.

Because the lantern will be of a lower amps draw/load, maybe even four fusible links between the four negative traces on the bottom cap PCB is possible? ( 5 or 10 amp flat SMD fuses are cheap, and if one cell manages to contact then the fuse for that leg can blow to open the short.

I do like this plastic riser to prevent reversed cells from contacting though, especially if one cell gets inverted accidentally at night. >> Q8 modding - #1202 by 5ar

Please put me down on the interest list for one.

This looks great! Thank you all for the hard work you are putting into this project.

Count me in on the interest list please.

Looks like a great bit of kit.

Definitely agree with keeping the default modes simple!

Also while I think USB charging is really important in a lantern, I don’t think the ability to act as a power bank is that important if increasing cost and complexity. Actual power banks with quick charge are so readily available, light and compact that probably most people take one tramping, letalone car camping.

Interested

Hi,

Interested in 1 (depending on price).

Good to see this suddenly taking off and taking shape with a Team now.

Thanks for your hard work.

Appreciated.

Cheers,
S-L :slight_smile:

At the moment it’s mostly DEL doing all the work, designing a circuit which will handle light and USB in a SRK-style form factor. It may well be the hardest part of this project.

Physical host design seems like it’ll be a fair amount of work too, due to the USB port(s) and all the lantern-style adjustments to the head.

Since I’m doing firmware, I’ve got the easy job… all I have to do is port my FSM toolkit to the new driver and tweak the calibration and settings. Most of the work there was done months ago.

Ok, I thought I already joined this one………but I dont see it so,

Put me in for at least 1, more than likely 2-4 if the price is not too high.

Thanks,
Jim

I am working on doing a modification to the prototype to make the head of the lantern more stronger, (using a center bolt to hold the head & globe/shade together) but testing with two LEDs. Also will revise the drawing design to show the change that works with o-rings. Also adding tripod mounts to the bottom as some mentioned that would be as good option, (for lighting up a campsite or back yard are on a tripod.

Please add me to the list for 1.

Thanks!

This project has me excited!

Please add me to the interest list

If the LED (s) will not be in the center, and instead a bolt will be there, I’d rather see three (or four) LEDs used, so the light doesn’t become bi-directional with shadow lines between the outputs of the two LEDs.

But you’re testing it, so I’ll trust you to come up with what works. :smiley: