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

You mean like those hoverboards with no balance circuitry that were catching on fire?

It would be a nice looking feature, but microUSB has the practical aspect in the field use. Chance to find a common microUSB cable if one get lost is higer than getting an proprietary charge adapter.
For long-term use it could even be helpful to add an USB c-type plug (additionally to microUSB maybe).

I should read the whole threat :person_facepalming: . but that’s great, so charging and running the light should pose no problem.

About usb plug charging. I still think there are better options, specially because it’s a lantern the designer(s) is/are less restricted with space. Maybe the charging cable could be stored secured in/on the lantern. And for long term usage I think it’s better to avoid ubs plugs in the lantern. Check the forum and see how many negative comments there are on usb charging. The convoy or olight way also allows for better water proofing then some silicone thingy over the usb input.
But before all this can be discussed it is needed to know the cell configuration. If it’s 4S or 2S2P usb charging is out of the question I believe.

This prototype is 4P configuration, so charging the four cells is safe. I prefer 4P config as the lantern can be run on 1, 2, 3 or 4 cells, is safer, etc. I have tested a TP4056 1A USB charger on 4P 18650 cells and they charge no problem during the day. ( also charging the cells at 250ma each when in 4P series the cells don’t heat up, and last longer over time. A TP charger board can charge the light while its still running, (with light on medium or lower modes so the charger can output more power than is being drawn to both charge cells and power the driver, also that would basically run the light from the USB charger effectively, as once the cells reached full charge the charger would sort of ” float” charge the cells & run the lantern. meaning it can be run from a 12 volt USB adapter, wall USB adapter, etc.

I don’t really understand. So if you run the light while charging, it still charges the cells at 1A AND runs the light. So it’s putting out like 2 or 3 Amps? Or is it drawing the current from the cells that are being charged?

I find 250mA really low takes like more than 12h to charge. Wouldn’t get away with 500mA ,don’t think it woud heat up the batteries that much but he charging board might get hotter?

Don’t know much about electronics but I think I’d rather see the cells disconnected (electronically) from the driver while charging and that the light is run straight from the input. That way the light is able to run without batteries in it. I don’t even know if that is possible at all but that’s what’s inside my head.

I added bold to the important bit above. The charger is supplying 1 Amp to the batteries, split equally between the four batteries installed so they each get 250 ma. As long as the LED is drawing less than the charger is putting in (1 Amp in this case) the batteries are being charged. So assuming that nothing is lost to inefficiency, the formula is:

(I (charger) - I (LED)) / (# of batts) = I (battery)

You got it. Right now the prototype is running a 2-7135 Q-Lite driver, meaning on high it draws 700mA. the TP4056 i tested still “trickle charged” the cells when running, but charged faster if the lantern is run on medium mode. (roughly 390mA from my tests on this prototype.

as mentioned to lazy-r-us, right now the prototype is running a 2-7135 Q-Lite driver, meaning on high-mode it draws 700mA. the TP4056 i tested still “trickle charged” the cells when running the lantern, but charged faster if the lantern is run on medium or low mode. (roughly 390mA from my tests on this prototype on medium-mode) If you run the batteries down to the point the driver low-voltage warning cuts-in then yes it takes a long time to recharge, but average use of 4 to 5 hours in 1 night don’t drain them down much at all, so they onyl need to be topped-up so to speak.

Interested as well.

Also interested, going to follow this post.

Very interested, loving the progress!

Interested, but also holding off committing until a price is mentioned.

(I did not see one but may have missed it in the pages of reading. )

With the 2x7135 and TP4056 charger, this lantern sounds like it would be perfect for camping or long term use, plugging in to a solar panel to top off the cells during the day.

I’m not familiar with the SRK battery compartment setup, but just off hand, with the space of 4x18650, I imagine it wouldn’t be very difficult to rig a carrier for using 3xAA, (or maybe 4 or 5 in 3s2p?) or maybe 3C primaries for anyone not wanting to use Li-Ion?

Sounds great the way the prototype is configured; definitely can’t wait to try one out! :heart_eyes:

The battery compartment is quad-bored resulting in a cloverleaf cross-section. If you wanted to use a 3xAA carrier, you’d have to bore out the battery tube. Doing that would make the 18650 “slots” less stable. It would probably be impossible to hold 1,2, or 3 cells, meaning you’d always have to use 4x 18650. That’s not desirable. I don’t know if it’s possible to make a 4xAA carrier with a cloverleaf cross section. If you were able to get one of those made to fit in the 4x 18650 tube, that would be nice. But then our drivers would have to be made for higher voltage or risk burning up. If you want a drop-in solution (no need to change drivers) you could make it shaped like 4xAA cloverleaf but only hold 3xAA cells. That’s your best bet.

I came across this thread after a while, reading the last post about slow charging with 4P battery config.

Wouldn't be possible to add another port or maybe even 1 port per battery and charge it with multiple microUSB inputs? maybe divided by diodes, so i you just have 1charger than good you charge slow, add another one and you charge double as fast, 1 charger per battery charges it 4 times faster. Many powerbanks nowadays have at least 2 ports of 2+ Amps capable so 4A will be feasible. Dunno about the circuitry tho. Just brainstorming here.... :|

interested

During traveling i don’t think you will have 4 powerbanks and 4 usb-cables with you for charging the lantern.
Also using chargers with different current would result in different voltage cells, which for sure isn’t good.

My idea was just about 1 powerbank as I wrote, as almost every 10Ah + nowadays can deliver more than 3A. You have more than one usb port in the single powerbank and also you can use Y cable to use just powerbank to its maximum rated power delivery. And the cells would all be charged as it would one input so always parallel charging. With lab PSUs it is not uncommon to parallel them to double to Current or put them In series (not this case obviously) to Double the voltage

With my phone I cannot post images but this was the idea

Ahh, I see. Ok, thanks David.
Not that I intended to use primaries, but the thought occurred for a second, (based on someone’s earlier post) that adapting a holder for primaries might be useful in a pinch or for the non-lithium-ion initiated. The idea of a carrier was short sighted however; using primaries would also introduce problems related to someone mistakenly trying to recharge them using the 4056 since it would see the voltage range for Li-Ion cells and, it seems, provide a charge current, yuck :confounded: :person_facepalming:

You have to consider not every traveller has a 10Ah+ (let’s stick to capacitiy, so 40Wh+) powerbank. Means it has to be large enough to fit 4x 18650 cells and weight around 300g if it’s made of plastic.
Most can deliver 1A, some have only one port wich can deliver up to 2A.
Even power plugs only deliver at best 2,5A.

It’s better to stay realistic.