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

[quote=sbslider]
Ok, I have been out of touch a few days and am catching up.

dekozn, you are currently number 363 on the interest list, are you looking for a second lantern, or just lobbying for 2700K emitters
[/quote ]

For now I just want one lantern

Please add me to the list for one!

Respectfully

Seems tha an USB Type-C plug only charges $0.57 and is already the standard of the future.
https://aliexpress.com/item/1x-16P-16-Pin-USB-3-1-Female-socket-Connector-for-repair-mobile-camera-MP3-MP4/32769193616.html

Apple will use USB-C in future iPhones and future smartphone chargers in the EU are planned to be USB-C.
http://www.digitaleurope.org/DesktopModules/Bring2mind/DMX/Download.aspx?Command=Core_Download&EntryId=2630&language=en-US&PortalId=0&TabId=353

Would be an advantage if the charging cable can be plugged in into the lantern without looking for the orientation of the cable. DualSide microUSB cables are still not that common and magnetic USB adapter cables are still above 10€.
An alternative could be at least to illuminate the USB Port :slight_smile:

If the additional cost for USB c is that low I would also prefer the use of USB c, but I am still not really happy with the planned low 1A charging current. Yes, it’s enough for the intended purpose of slow solar charging over the day, but I’m sure that many (especially non flashaholic) users would be happy if they don’t need to take out the batteries for reasonable charging times, so how much would it cost to implement power delivery or at least increase the current (the Olight X7r can take up to 4A)? Or would an classic DC plug be an option?
And how do you want to implement the powerbank funktion? Using the USB c with a dongle or installing an additional USB A port?

Thank you, angerdan, that was useful information for the USB connection poll thread:

Done, you are number 889 on the interest list.

Wow, that 3000k looks NICE for a lantern. I prefer a nice warm tint for lanterns and that looks amazing. I LOVE the progress being made and can’t wait to order a bunch up. THANK YOU!

good points on the USB-C. I do like the ambidextrous design of the interface being able to plug in either direction.

its not really limited to 1 amp, we can probably have the charge current up to 1.5A maybe at the most, to be practical and allow the lantern to accept charging from more various smaller & lower powered charging devices, (the tests i did is with a TP4056 charger circuit and i only have a 1A version in the V1, but i did a dual TP4056 test last fall and found most all smaller USB power devices could not sustain enough voltage to run them) My thoughts and tests from experience i found that trying to pull 2+ amps from most small solar panels less than 25 watts, from most generic cig-socket adapters, Even most portable power banks i have tested and had can not sustain 2 amps very well without voltage drop or overheating. i seen the voltage drop to much and damage chargers/adapters from over-heating or not charge the cells at all with the low voltage. (as many charging circuits will cut off charging if the voltage drops below 4.5 volts. Only the massive brick-sized Interstate booster/powerbank i have seems to be the only one i have that can sustain a 2 amp USB load and keep the voltage above 4.8 volts. The built in USB charger ports in my RV can sustain 1.5 amps but not much more.
Most people will likely be charging the lantern from Car USB adapters, panels, RV USB ports, small wall warts, etc. during the day when the lantern is not used anyways, and no real need to rush charge it in a hour or two. That is the problem when trying to pull to much amps from weaker USB power sources, is the 5.0 volt standard output drops substantially thus causing the charging circuit to either shut off, or go into a “switching off/on” cycle because of the voltage fall & ending up with not charging the cells at all & overloading the USB power source. 1 amp to 1.5 amps for this needs to be the upper limit really to make it more versatile and able to charge from a more wide range of USB power sources, because that is it a lantern, its likely to be used more in locations where grid-power is not available. Its better to sacrifice some charging time and have it more compatible with a wider range of USB power sources. Its better to have the lantern more versatile for charging from lower USB power sources than it is to have a fast-charge rate. For anyone to want a fast charge rate, its better to just have a second set of cells or use a external 4-bay charger when at home or on-grid power. 1-amp charging it better suited for this application to work with most power sources.

That’s weird and not how a power supply should work.

A USB power supply can maintain the 5 volt while supplying the full current. And it can’t deliver more than the rated current so you can’t overload a power supply.
There is no reason to limit the chargecurrent in the charger itself to a low current. The power supply should and will limit the charging.

A powerful power supply that can output multiple amps and will charge it faster but a smaller power supply, like a solar charger, will charge it with less amps and slower.

That’s the law of demand and supply.

Good point DBSAR, I didn’t thought about that as a possible problem. Good to know that you put some thought and testing into that decision. But maybe we could still use two TP4056 if one shuts down if the power source couldn’t handel the current. This could be done automatically with some sort of voltage drop detection or manually with a simple 1A / 2+A switch next to the charging port.

In theory, yes.

When I’ve measured actual USB power supplies though, I haven’t found any which actually maintain full voltage at full power. Most are cheap and tend to sag. Sometimes even at just 500mA.

That’s what i believed one time, until i began to use USB monitors to test my powerbanks, panels, and various adapters. A 7 watt panel i tested dropped to 3.15 volts with a 1.5 amp load. The ports in my RV can sustain 5 volts up to 1 amp, then it drops as the amps increase past that, and while i can get close to 2 amps from the ports, the voltage sags to 4.3 volts at that amperage load. (I now use a similar model to this: USB 3-in-1 Voltage/Current/Capacity Meter
also the same thing with smaller powerbanks, the voltage sags badly when the load goes up, especially on those with two USB ports. Only the best, largest, and most powerful power bricks & booster i tested can keep the voltage above 4.9 volts with a large amp load.

That would be a good idea if its electronically possible, (and not to expensive) to have a dual charging rate design, (switchable somehow between a 1 amp trickle charging for use with lower power USB sources, then a higher rate 2+ Amp charging for use with a larger 120 volt USB power adapter. ( such as a tiny DIP-switch nex to the USB port on the lantern.

@Toykeeper and DBSAR, all of my USB power supplies can easily do 2A continuous without sagging down 5V, or even higher. You just need to have quality sources.

However, I still think we should stick to 1.5A charging using the TP5000 IC, as to support most USB chargers as you both said, and to support cheaper long cables.

I have had cheap cables from friends actually heating up and losing a lot of power just to thin wires.

cables definitely can cause voltage sag with small gauge wires. I never got the chance to really test out the TP5000 yet on any devices or charging.

The part currently being pursued is the BQ25895 made by Texas Instruments. I have been trading emails with an applications engineer at TI regarding using this part with less than stellar USB power source. Here is a bit of the conversation

ME: Can the Ilim pin configure the chip to limit the input current, and hence the current delivered to the batteries being charged? I think what I really want to do is limit the input current such that I don't load down a USB power source, and allow as much current as is available to charge the batteries. Likley want to limit the input current being supplied to VBUS to 1 or 1.5A. Is this a simple as selecting the correct resistor on the Ilim pin (pin 10).

TI: yes, the ILIM pin limits input current which is directly proportional to output current SYS and BAT. If you have no load SYS, then the relationship is simply efficiency=(VBAT*IBAT)/(VBUS*IBUS) where IBUS is clamped to ILIM resistor setting. The charger also has the VINDPM feature and ICO features which prevent the charger from collapsing its input source.

What is key is the last sentence from the TI engineer. I was reading about the VINDPM and ICO features last night. Basically the IC senses the input voltage and input current being drawn from the source, and limit the current into the batteries based on several variables. If the battery charging is demanding too much current for a given source, and causes the source to droop, the IC will back off on the demand to keep the source from collapsing due to excessive current. Seems like this will mitigate having to artificially limit the charge current into the batteries. The IC is also able to detect what sort of USB source it is, and base the current limit from the source based on that sources characteristics.

From the data sheet, The bq25890 contains a D+/D– based input source detection to set the input current limit automatically. The D+/D- detection includes standard USB BC1.2, non-standard adapter, and adjustable high voltage adapter detections. When input source is plugged-in, the device starts standard USB BC1.2 detections. The USB BC1.2 is capable to identify Standard Downstream Port (SDP), Charging Downstream Port (CDP), and Dedicated Charging Port (DCP). When the Data Contact Detection (DCD) timer of 500ms is expired, the non-standard adapter detection is applied to set the input current limit.

This is a very capable part which DEL selected. BQ25895 datasheet

it would be good if a charging circuit was able detect the current & voltage from a USB source to adjust the amp load/charging rate to sustain the needed voltage without to much sag, especially with solar panels which most have no regulation for the voltage sag when put under amp loads approaching their maximum output efficiency.

Fantastic idea sbslider, the BQ25895 seems to be exactly what we are looking for. The wide voltage range with automatic step up/down is perfect to deal with unstable power surces and would us even allow to add an additional 12V input for even faster charging in the car/ trailer or with larger solar panels.

I am interested x2