This isn't a standard solar light. It's got very unique solar panels, and even more unique circuitry that makes it very different from ordinary solar lanterns.
This light was sent by Steve at Nokero (No Kerosene) a few years ago, so hopefully the circuitry is still applicable. The Nokero website appears to be down now, so I'm not sure if they're still making these.
The reason this light was designed is to provide safe illumination to parts of the world with no reliable electrical infrastructure. It uses good quality solar cells and a LiFePO4 battery that potentially offers around 2000 charge cycles with low loss of capacity over time.
The most interesting parts of the circuitry are the current regulator, which took a lot of deducing to identify. The use of a Texas Instruments microcontroller that can monitor voltage accurately for circuit control, the unusual charge control technique of using the LED as a shunt load, and the very efficient use of a MOSFET as a very low drop alternative to the more common solar panel diode.
The solar panel's transistor is only turned on when the panel's voltage exceeds the lithium cell voltage. It's effectively being used as a software controlled zero-loss diode (Active rectifier).
That suggests that charge limiting is mainly based on the LED being used as a shunt load.
The use of a LiFePO4 cell is notable, as it is safer and more rugged than the typical rechargeable lithium cells used in most phones and appliances. Although the technology has lower energy density than the classic 3.6/4.2V lithium cells, it offers greater capacity retention over its lifetime, and a much less volatile electrolyte.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
This light was sent by Steve at Nokero (No Kerosene) a few years ago, so hopefully the circuitry is still applicable. The Nokero website appears to be down now, so I'm not sure if they're still making these.
The reason this light was designed is to provide safe illumination to parts of the world with no reliable electrical infrastructure. It uses good quality solar cells and a LiFePO4 battery that potentially offers around 2000 charge cycles with low loss of capacity over time.
The most interesting parts of the circuitry are the current regulator, which took a lot of deducing to identify. The use of a Texas Instruments microcontroller that can monitor voltage accurately for circuit control, the unusual charge control technique of using the LED as a shunt load, and the very efficient use of a MOSFET as a very low drop alternative to the more common solar panel diode.
The solar panel's transistor is only turned on when the panel's voltage exceeds the lithium cell voltage. It's effectively being used as a software controlled zero-loss diode (Active rectifier).
That suggests that charge limiting is mainly based on the LED being used as a shunt load.
The use of a LiFePO4 cell is notable, as it is safer and more rugged than the typical rechargeable lithium cells used in most phones and appliances. Although the technology has lower energy density than the classic 3.6/4.2V lithium cells, it offers greater capacity retention over its lifetime, and a much less volatile electrolyte.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
"nokero" (No Kerosine) sounds suspiciously like a Japanese abbeviation of "Engrish" words: like "rimokon" (remote control) or "eakon" (air conditioner) or "pasokon" (Personal Computer).
isn't MOSFETs have internal body diode? that low side MOSFET connecting solar panel then always charging battery when solar panel produce more voltage than LiPo4 is charged to
The reason LiFePo4 haven't taken over is because device manufacturers are relentlessly pursuing thin for the sake of thin, and the added 0.72mm of thickness added by the larger cells would be converse to this.
As it is they already controlled-overcharge standard lithium cells as high as 4.4V to cram as much capacity into a tiny footprint as possible.
With the push towards laptops being thin enough to shave with as well, that's not exactly a saving bastion either.
There's definitely some planned obsolescence involved here as well, since sealing a cell that's being punished at 4.4v into a Device will make it die within two years and "encourage" its owner to replace the entire Device before its prime, especially coupled with slowing the Device down with bloated firmware patches and equipping everything with AMOLED screens that look nice for the first maybe year if you take care of them before starting to show visible burn by the second, before just ending support outright.
yes I am bitter why do you ask….
One of the worst things about all of this? LAPTOPS ARE BECOMING PHONES. Proprietary batteries locked inside of the PC, chassis designs that're harder to open, soldered down RAM, SSD, secured bootloaders, riveted in keyboards, and yes, AMOLED screens with EDID DRM locks.
I love collecting older computers, including laptops.
I will be basically unable to collect any "older" laptops from the incoming generations, as I can't repair them. I can't add RAM (which at this rate is becoming an increasing problem, thanks software bloat), I can't replace failed storage (very common problem), can't replace failed keyboards, can't easily replace failed batteries (which can easily become actual fire hazards! as discussed in this video – I had a Pentium 4 based machine try to set my dad's house on fire), and will have to increasingly worry about replacing failed and burned-out screens which will also be increasingly difficult if not impossible when I start finding them on the open market in ten years.
Hi clive just a question i made a solar light with a cellphone battery. It works but very dim. When i conect the light straight to the battery though its very bright. What have i done wrong? Please let me know
Nokero is located here in Denver, CO
If only fashionistas would prefer small phones…
And not one mention of the Edison screw type hanger ?
I agree with you, Clive, about LiFePO4. I think its an amazing technology. Compared to other Lithium batteries, LiFePO4 are quite resilient and fault tolerant. I have a 15-year-old 100Ah battery (4 cells in series for ~12v) that still has close to 90% of its capacity, even though for a number of years it was continuously charged by a 2A lead acid charger (I do not recommend charging that way, but it was before I owned it). They're extremely efficient when charging, have a very low leakage rate, and do not get hot when used within their design specs. In fact, charging feels like it cools the cell slightly. Their only "real" downside, and the reason you don't see them in cell phones, is because of their energy density. An 18650 LiFePO4 is usually between 1200mAh and 1800mAh, while Lithium Cobalt 18650s often run about 3400mAh in capacity.
I need some of these, cannot get any 🙁
I'd never seen this video. So pleased I clicked to watch this coming from your clone ripoff vid.
Love seeing these things and less throw away stuff.
If you leave it in the sun it blinks when it's charged. Could just be the it's set to over charge then discharge directly in the programing? or it's programed to overcharge and activate a separate dump, that's why the input is more precise than the output?
What happened to this company? The website is gone and no products are available anywhere…
They seem to be no longer around.