Question about batteries and solar charging

LEDrock

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You would be surprised how much the Chinese do to try and save a fraction of a cent on manufacturing costs. There have been fake batteries made before with other tiny batteries inside of a bigger cell. Even Rayovac and others have played the game by putting a Sub C battery inside a rechargeable D cell at one time.

Here's a slightly different question that's related to the first. What do you think of solar panels bought from Amazon that are simply a panel with 2 wires coming out of it that would be connected directly to a battery? Is that all that's needed to charge a battery? Does the panel's voltage factor into it?

Here's one I found. What do you think? https://www.amazon.com/dp/B07TVHMMSK/?tag=cpf0b6-20

Or even something like this? https://www.amazon.com/dp/B01N38GZFD/?tag=cpf0b6-20
 
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Dave_H

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I'm surprised the battery your light had was so low in capacity. I didn't know 100Mah AAA's existed. My lights ($1 at Menards before 100% rebate offer) came with 300Mah battery. I did a runtime test with it and found it runs the light for 5.5 hours. I also have 600Mah batteries that I assume would run twice as long.


Keep in mind that this is a dollar-store product and cost needs to be kept down by whatever means. Some solar lights come with cells of higher capacity than the charger can keep up with in some conditions. Not bad, just wasted capacity and higher cost. With NiMH it's better to not reach capacity and overcharge anyway.

I have found solar NiCd AA's as low as 150mAh, and a variety of NiCd/NiMH sub-cells including 2/3AA, 2/3AAA and even 1/3AAA (200mAh). It is all about keeping cost and size down.

My cheap spotlight was running most of the night with good day of sunlight (6-7 hours). Run time depends on the LED brightness/current. I assumed cell could charge to 100mAh in a day under good conditions. Cell capacity was bumped, but I also increased LED brightness by changing an inductor. Just an aside, not important when just charging cells as OP does.

Dave
 

Dave_H

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I agree, the only benefit is if it has a light sensor that shuts it off and you charge a large battery up and when you have an overcast day it can use the extra capacity to power the light but it won't be restored by solar charging.

My estimate doesn't account for efficiency lost in the charging circuit itself. For example many solar charge IC datasheets show connection between solar panel and cell through a diode (some are direct). Schottky diode drop should be less than 0.5v but for 1.25v cell is substantial.

Also unknown how well the solar panel and cell are matched for optimum transfer i.e. at maximum power point, hopefully somewhere close.

Dave
 

Lynx_Arc

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Here's a slightly different question that's related to the first. What do you think of solar panels bought from Amazon that are simply a panel with 2 wires coming out of it? Is that all that's needed to charge a battery? Does the panel's voltage factor into it?

Here's one I found. What do you think? https://www.amazon.com/dp/B07TVHMMSK/?tag=cpf0b6-20

Or even something like this? https://www.amazon.com/dp/B01N38GZFD/?tag=cpf0b6-20

Consider panels like cells in a battery. If a panel has a single "cell" then it is the voltage of that cell alone. You can buy batteries with multiple cells like lead acid batteries and you can buy packs of cells wired together to get higher current output and/or higher voltage and the similar applies to solar cells. While I'm not anywhere near an expert on solar tech, it is obvious that higher voltage panels have multiple cells in series and larger current output panels have either larger individual cells or many paralleled and put the arrays in series to get required voltage. From what I have seen panels can put out a lot higher voltage than they are related and under a load they "sag" to lower voltages and the sunlight on them can vary widely greatly affecting their output. Matching solar cells to loads is likely a challenge if the panel has overall more power (in wattage) than the device can handle which could cause the voltage to float higher than the device is made for and cause damage. This is why they have some sort of regulation circuitry on panels a controller or something like that to limit the voltage to a set level. Most devices are designed to take a certain voltage and as long as that voltage isn't exceeded it can be put on ANY source from adequate amps to 1000 amps even with no issue as the device will only consume what it needs if it draws half an amp then it will draw that much and the other potention 999.5A capability is unneeded. There are ways to get around issues of solar output of cells widely varying due to sun output and weather and daytime and shade and clouds etc one is by charging a big battery and using that to charge and run smaller items it can be as a buffer but may need to be disconnected from solar to use it. Another way is to match the output of the solar cell with the load such that it cannot exceed the load regardless of the light output.
2 wires is all you need from a solar cell to use access its power, but matching the cell to your device is where it can be tricky.
 

Lynx_Arc

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My estimate doesn't account for efficiency lost in the charging circuit itself. For example many solar charge IC datasheets show connection between solar panel and cell through a diode (some are direct). Schottky diode drop should be less than 0.5v but for 1.25v cell is substantial.

Also unknown how well the solar panel and cell are matched for optimum transfer i.e. at maximum power point, hopefully somewhere close.

Dave
I doubt they engineer them with much care for efficiency rather than focus on cheap cost and something that works well enough for a long enough time that people will buy them to "try them out" and maybe buy others and 6 months later when they start to die the stores will run out of them or there will be other folks still buying them for the first time.
 

Dave_H

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Here's a slightly different question that's related to the first. What do you think of solar panels bought from Amazon that are simply a panel with 2 wires coming out of it that would be connected directly to a battery? Is that all that's needed to charge a battery? Does the panel's voltage factor into it?

Here's one I found. What do you think? https://www.amazon.com/dp/B07TVHMMSK/?tag=cpf0b6-20

Or even something like this? https://www.amazon.com/dp/B01N38GZFD/?tag=cpf0b6-20

Yes you could use a stand-alone solar panel (and a much larger one) but requires at least minimal interface circuit to the cell(s) being charged. You need to limit current and not overcharge. Also a blocking diode prevents leakage back into the solar panel during darkness.

Charging a single cell with a poly-crystaline panel requires at least four solar cells in series. You see this on some solar garden lights; or multiple banks of four in parallel for higher current.

First item seems to have two banks of three cells, which is a bit short for a single cell. A little pricey, otherwise would have been OK. Keep in mind 400mA is probably peak, expect lower average.

Second item, 12v panel is way high for single cell charging. Appears to be two 6v banks in series. You could drop the excess voltage but it would be very inefficient. Some sort of step-down converter would be required. Depends how far you want to go with this.

Dave
 
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LEDrock

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Consider panels like cells in a battery. If a panel has a single "cell" then it is the voltage of that cell alone. You can buy batteries with multiple cells like lead acid batteries and you can buy packs of cells wired together to get higher current output and/or higher voltage and the similar applies to solar cells. While I'm not anywhere near an expert on solar tech, it is obvious that higher voltage panels have multiple cells in series and larger current output panels have either larger individual cells or many paralleled and put the arrays in series to get required voltage. From what I have seen panels can put out a lot higher voltage than they are related and under a load they "sag" to lower voltages and the sunlight on them can vary widely greatly affecting their output. Matching solar cells to loads is likely a challenge if the panel has overall more power (in wattage) than the device can handle which could cause the voltage to float higher than the device is made for and cause damage. This is why they have some sort of regulation circuitry on panels a controller or something like that to limit the voltage to a set level. Most devices are designed to take a certain voltage and as long as that voltage isn't exceeded it can be put on ANY source from adequate amps to 1000 amps even with no issue as the device will only consume what it needs if it draws half an amp then it will draw that much and the other potention 999.5A capability is unneeded. There are ways to get around issues of solar output of cells widely varying due to sun output and weather and daytime and shade and clouds etc one is by charging a big battery and using that to charge and run smaller items it can be as a buffer but may need to be disconnected from solar to use it. Another way is to match the output of the solar cell with the load such that it cannot exceed the load regardless of the light output.
2 wires is all you need from a solar cell to use access its power, but matching the cell to your device is where it can be tricky.

So let's say all I wanted to do was connect a solar panel directly to a AA battery (1.2V NiMH with 2000Mah capacity) to charge it fully in 10 hours. What would the voltage and output of the solar panel have to be? My guess is a 1.2V panel that puts out 200 MA. Would I be correct?

Of course, this doesn't involve any converters or controllers. It would just be a matter of keeping an eye on it and testing the battery every so often to make sure it's not about to overcharge. With practice, I could figure out how long to leave it in the sun.
 
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Lynx_Arc

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Yes you could use a stand-alone solar panel (and a much larger one) but requires at least minimal interface circuit to the cell(s) being charged. You need to limit current and not overcharge. Also a blocking diode prevents leakage back into the solar panel during darkness.

Charging a single cell with a poly-crystaline panel requires at least four solar cells in series. You see this on some solar garden lights; or multiple banks of four in parallel for higher current.

First item seems to have two banks of three cells, which is a bit short for a single cell. A little pricey, otherwise would have been OK. Keep in mind 400mA is probably peak, expect lower average.

Second item, 12v panel is way high for single cell charging. Appears to be two parallel banks of 24 cells in series. You could drop the excess voltage but it would be very inefficient. Some sort of step-down converter would be required. Depends how far you want to go with this.

Dave
12v panels can charge 12v larger lead acid batteries directly as long as the continual charging rate is not over trickle charging them or you have a controller to shut off charging and you can then use the battery to charge other devices. This is a common method used. USB 5V charger setups are out there that the only issue with them I know of (and I don't know all issues) is the current output may drop too low to charge some devices at all.
I think you are getting deep into solar setups far beyond my limited knowledge and unless someone who is more experienced than I am steps in I won't be able to give you much info. I've not delved into solar other than reading about it and a knowledge of electronics in general of some circuitry used in it. I have little to know direct knowledge of solar controllers and how they work so setting up something more than a throwaway solar garden light is beyond my expertise at this time. They do make buck converters to step down voltage but for purposes of charging if the cell has the ability to put out more than what is a safe charging rate and can overcharge the cell (doesn't have a shutoff) then it can damage your battery over time.
 

Lynx_Arc

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So let's say all I wanted to do was connect a solar panel directly to a AA battery (1.2V NiMH with 2000Mah capacity) to charge it fully in 10 hours. What would the voltage and output of the solar panel have to be? My guess is a 1.2V panel that puts out 200 MA. Would I be correct?
Nowhere near that simple long term. Yes you could get a setup to charge the battery fully like that but there is many considerations to solar charging like not having continual full output from the cell due to moving sun and weather/clouds, loss in charging due to heating the cell up, overcharging damage to the cell if if you don't stop charging when full also. Over time you could fully charge the battery but it could be slowly damaged and lose capacity such that normal amount of good cycle use would suffer. In order to charge it properly and not harm the battery in doing so you likely will need a larger solar cell and higher voltage to incorporate charging circuitry and also account for a more average sun output as solar cells are labeled for max output a 200ma output cell over 10 hours may only put 1200mah into the battery due to losses and not having peak sun on it. You charge it the next day for 10 hours and only 6 hours are needed for it to reach full and for 4 hours it literally cooks the cell overcharging it and damaging it unless you have some way to detect it is full (a smart charger) you would have to estimate how much charge it got and limit overcharging or undercharge it some.
 

LEDrock

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Nowhere near that simple long term. Yes you could get a setup to charge the battery fully like that but there is many considerations to solar charging like not having continual full output from the cell due to moving sun and weather/clouds, loss in charging due to heating the cell up, overcharging damage to the cell if if you don't stop charging when full also. Over time you could fully charge the battery but it could be slowly damaged and lose capacity such that normal amount of good cycle use would suffer. In order to charge it properly and not harm the battery in doing so you likely will need a larger solar cell and higher voltage to incorporate charging circuitry and also account for a more average sun output as solar cells are labeled for max output a 200ma output cell over 10 hours may only put 1200mah into the battery due to losses and not having peak sun on it. You charge it the next day for 10 hours and only 6 hours are needed for it to reach full and for 4 hours it literally cooks the cell overcharging it and damaging it unless you have some way to detect it is full (a smart charger) you would have to estimate how much charge it got and limit overcharging or undercharge it some.

Thanks! I guess it's more complicated that it seems. I'm not much of a techie like I wish I was. I'll probably just stick with doing things the conventional way instead of buying or scavenging parts and trying to construct my own. Those solar chargers that have an attached 10,000Mah battery (often bigger) sound good, but then that doesn't charge conventional batteries. They're built to charge up smartphones and tablets. They have AA and AAA solar chargers, but they cost just as much and have low reviews. That's why I was thinking of just making my own.
 

Lynx_Arc

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Thanks! I guess it's more complicated that it seems. I'm not much of a techie like I wish I was. I'll probably just stick with doing things the conventional way instead of buying or scavenging parts and trying to construct my own. Those solar chargers that have an attached 10,000Mah battery (often bigger) sound good, but then that doesn't charge conventional batteries. They're built to charge up smartphones and tablets. They have AA and AAA solar chargers, but they cost just as much and have low reviews. That's why I was thinking of just making my own.
If the solar chargers have USB ports just look for a smart USB based charger for your cells and use it.
IMO if you aren't a survivalist or one that likes being away from a main power source for many days/weeks at a time the expense of a solar charger setup that will do a good job quickly enough may not be a good investment. I don't have any prices but likely you could get into the 50 dollar range easily to charge a pair of AAs in a day and the amount of space the solar setup requires you could just carry extra rechargeable batteries on you instead and a charger that operates on main power and/or auto 12v systems and wait till you get power to recharge.
The solar chargers with the power banks are very likely way weaker and slower than you are led to believe. To recharge a 10,000mah power bank it would take about 50 watts of energy from a solar cell to do the job and small solar cells the right voltage are about 0.2W max likely less than 0.1W taking in consideration losses and would take likely 400+ hours to recharge it. the full sized cells on those things may be closer to 1W max or about 1/2 watt effective and take 80-120 hours to recharge or maybe several weeks with good sun. It would be better than nothing but if you can't stay in one place and wait for it to recharge expect moving for it to double or triple that amount of time even.
I would consider looking on Amazon at solar charging stuff and search CF there are a lot of people here that IMO are experts, as I'm just sort of tossing numbers I estimate at you that could be way off.
I typically ignore solar charging gizmos myself and invest in lights that are efficient and have low modes and power banks instead.
Solar power is best with large panels and people that are outdoorsmen and utimate survival gear in hurricane prone areas IMO.
 

LEDrock

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If the solar chargers have USB ports just look for a smart USB based charger for your cells and use it.
IMO if you aren't a survivalist or one that likes being away from a main power source for many days/weeks at a time the expense of a solar charger setup that will do a good job quickly enough may not be a good investment. I don't have any prices but likely you could get into the 50 dollar range easily to charge a pair of AAs in a day and the amount of space the solar setup requires you could just carry extra rechargeable batteries on you instead and a charger that operates on main power and/or auto 12v systems and wait till you get power to recharge.
The solar chargers with the power banks are very likely way weaker and slower than you are led to believe. To recharge a 10,000mah power bank it would take about 50 watts of energy from a solar cell to do the job and small solar cells the right voltage are about 0.2W max likely less than 0.1W taking in consideration losses and would take likely 400+ hours to recharge it. the full sized cells on those things may be closer to 1W max or about 1/2 watt effective and take 80-120 hours to recharge or maybe several weeks with good sun. It would be better than nothing but if you can't stay in one place and wait for it to recharge expect moving for it to double or triple that amount of time even.
I would consider looking on Amazon at solar charging stuff and search CF there are a lot of people here that IMO are experts, as I'm just sort of tossing numbers I estimate at you that could be way off.
I typically ignore solar charging gizmos myself and invest in lights that are efficient and have low modes and power banks instead.
Solar power is best with large panels and people that are outdoorsmen and utimate survival gear in hurricane prone areas IMO.

Well, I didn't want to mention it, but I'm not really a survivalist per se, but maybe a prepper. I was thinking in terms of what I could use to charge up batteries if there was a long-term power outage. I'm into flashlights, so I figured a free source of electricity to charge batteries for them made sense. After getting those AAA solar lights for free from Menards and seeing that they charged batteries that could easily be removed and put in flashlights, I was intrigued by the idea. That's what got me started on all this.
 

Lynx_Arc

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Well, I didn't want to mention it, but I'm not really a survivalist per se, but maybe a prepper. I was thinking in terms of what I could use to charge up batteries if there was a long-term power outage. I'm into flashlights, so I figured a free source of electricity to charge batteries for them made sense. After getting those AAA solar lights for free from Menards and seeing that they charged batteries that could easily be removed and put in flashlights, I was intrigued by the idea. That's what got me started on all this.

As I've "graduated" to lithium ion tech in my lights now all but abandoning nimh where I can and have a bunch of devices with them in them including half a dozen large power banks and over a dozen single cell ones I put batteries I scavenged out of recycling bins from laptop and tool batteries I'm pretty well set. I invested in an 18650 charger but these cheap DIY power banks can also charge batteries too if needed.
A single 18650 of 3400mah is about the power 10-12 AAA nimh cells have in them so if you have 4 of them you have about 40 AAAs in almost no space at all that are easily managed and a lot easier to recharge. I have several 18650 based power banks most of them are Anker brands from 10,000mah to about 18000mah I got for about $2-$3 per cell inside of them. I have 2 headlamps that use 18650s that are rated at about 900 lumens on turbo. I have a flaslight I paid about $20 with cheap charger and 3000mah batteries that says it will go 59 days on firefly mode, if only used 8 hours a day that is about 180 days at a little below 1 lumen and other modes too.
I would strongly recommend if it is within your budget to take a look at 18650 lights and if you have more money 21700 may also be of interest. I see you have a lot of AA/AAA lights, I was heavily invested in those too abandoning C/D and 9V type lights for them previously.
I use only 1 AA/AAA light often but I do have a few cheap plastic AA lights spread around as they are disposable battery and all I have a few cheap $4 18650 lights that are decent but I plan on getting better ones and replacing some of my AA/AAA lights with them around the place. The only advantage I see now in AA/AAA lights is size and cost and availability of batteries. It takes a little doing to get stocked up on enough 18650s and even 14500s as you can't buy them in most stores maybe vape shops sell them but YMMV at the quality of cells at those places I guess I'd rather order them online myself.
So for the size of a solar charging setup you likely can put 2-3 18650s in the space and have 20 or 30 AAAs worth in power so if it takes a day to charge a AAA battery you have enough power to last a month of charging, more if weather does not cooperate. That is a problem with solar charging it can be rendered useless by storms and cloudy days.
 
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LEDrock

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As I've "graduated" to lithium ion tech in my lights now all but abandoning nimh where I can and have a bunch of devices with them in them including half a dozen large power banks and over a dozen single cell ones I put batteries I scavenged out of recycling bins from laptop and tool batteries I'm pretty well set. I invested in an 18650 charger but these cheap DIY power banks can also charge batteries too if needed.
A single 18650 of 3400mah is about the power 10-12 AAA nimh cells have in them so if you have 4 of them you have about 40 AAAs in almost no space at all that are easily managed and a lot easier to recharge. I have several 18650 based power banks most of them are Anker brands from 10,000mah to about 18000mah I got for about $2-$3 per cell inside of them. I have 2 headlamps that use 18650s that are rated at about 900 lumens on turbo. I have a flaslight I paid about $20 with cheap charger and 3000mah batteries that says it will go 59 days on firefly mode, if only used 8 hours a day that is about 180 days at a little below 1 lumen and other modes too.
I would strongly recommend if it is within your budget to take a look at 18650 lights and if you have more money 21700 may also be of interest. I see you have a lot of AA/AAA lights, I was heavily invested in those too abandoning C/D and 9V type lights for them previously.
I use only 1 AA/AAA light often but I do have a few cheap plastic AA lights spread around as they are disposable battery and all I have a few cheap $4 18650 lights that are decent but I plan on getting better ones and replacing some of my AA/AAA lights with them around the place. The only advantage I see now in AA/AAA lights is size and cost and availability of batteries. It takes a little doing to get stocked up on enough 18650s and even 14500s as you can't buy them in most stores maybe vape shops sell them but YMMV at the quality of cells at those places I guess I'd rather order them online myself.
So for the size of a solar charging setup you likely can put 2-3 18650s in the space and have 20 or 30 AAAs worth in power so if it takes a day to charge a AAA battery you have enough power to last a month of charging, more if weather does not cooperate. That is a problem with solar charging it can be rendered useless by storms and cloudy days.

That little list of lights I have in my sig line is outdated by many years. I have about 30 lights of different types now, but none of them are of the 18650 type. I guess I've tried to stay away from them because then they get to be too specialized in that I'd have to get lights for them, and then that's all they'd be used for. However, I've been tempted by some deals on Amazon. Even Sofirn has a deal right now if you're a member of their Facebook group where they give you a code and you get the Sofirn S11c that comes with a 3000Mah 16850 battery that charges inside the light for $12.59 instead of the usual $17.99. It claims 1,000 lumens but reviews say it's closer to maybe 600. I just might end up with something like that.
 

Lynx_Arc

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That little list of lights I have in my sig line is outdated by many years. I have about 30 lights of different types now, but none of them are of the 18650 type. I guess I've tried to stay away from them because then they get to be too specialized in that I'd have to get lights for them, and then that's all they'd be used for. However, I've been tempted by some deals on Amazon. Even Sofirn has a deal right now if you're a member of their Facebook group where they give you a code and you get the Sofirn S11c that comes with a 3000Mah 16850 battery that charges inside the light for $12.59 instead of the usual $17.99. It claims 1,000 lumens but reviews say it's closer to maybe 600. I just might end up with something like that.

Go to their website and look around.
https://sofirnlight.com/
Looks like the SC11 is 11.99 there with battery and $3 shipping but there is free shipping not sure how that works though I bought my sofirn off Ebay. I don't like the mode choices on the SC11 light at all and don't see any output ratings on it for the modes either.
I thought about getting an SP40 headlamp so I have 3 headlamps as I take one to work, another to use around the house and a spare one as the one I have at home is not a removeable headlamp that can be used as a flashlight if needed and trying to charge it using the built in charger is a pain the rubber plug is so hard to get out I have to use a pocket knife or a pair of retractors.
 

Dave_H

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Low-cost solar AA/AAA charging schemes can be fun to play around with, no question. Problem with many (most?) is knowing how much charge has gone into a cell unless it reaches end of charge and circuit indicates this. You might be able to estimate based on hours of sunlight and known charge rate etc. but not convenient or predictable. Then it's getting into overcharge which is not good for NiMH. NiCd can accept limited overcharge at 0.1C (10% of capacity) e.g. 60mA for 600mAh cell.

I too charge Li-ion USB packs from a solar panel (using 5v USB lighter-plug adapter). The overall efficiency is not great, not much better than 60%. Panel is oversized but not doing much else at present. So, optimization is possible.

Most packs have some charge-state indication: 4 LEDs, or single LED flashing or changing colour or going off, when charging. NB most single-cell ones don't indicate remaining capacity while being used; kind of up to the user to know based on usage.

I've also charged single 18650's with a solar setup but it's a bit unwieldy; and the charge cycle being interrupted doesn't help.

Dave
 

Dave_H

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Sometimes you find a device which could do a reasonable job of charging cells. I happened on a small solar pump controller which runs from 4xAA. Its 5"x7" panel by my estimation could charge at up to 500mA peak. I has a charge state LED, so at least it terminates and indicates full charge. I could do a test though not today as it's overcast and rainy.

Regular price of this setup was about $40 and I would not have bought it if not seriously discounted; but you might find something similar.

Dave
 

Lynx_Arc

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I think with solar power you just have to worry about having enough for uninterrupted (mostly) charging in a short enough time frame to be useful. My issue is many people have this romantic idea that they can save money by recharging using solar and in an emergency instead of relying on extra batteries they can recharge fewer ones with it. The problem is that batteries have gotten affordable and 18650s hold a lot of energy so much that if using the very efficient LED lights today with lower modes the cost of a few extra batteries vs a decent output solar setup is a no brainer. One could buy a dozen 18650s and go months at 5-15 lumens lighting without charging a single one of them. I cannot see except for someone that is a survivalist in remote regions if you are without power for longer than a week with no end in sight it may be time to relocate to somewhere else or invest in a gas powered generator and 4-5 5 gallon containers filled with gas. Most of us have vehicles which you can charge a bunch of batteries from then run the engine at idle for an hour or two to recharge it and likely use less than a half gallon of gas or find someone with power to visit for an afternoon and take a power strip with you and all your chargers and batteries and gets recharged.
I just thought of a solution that few every mention for solar charging in emergency situation. A solar car charger setup not a trickle type charger but a larger output one could be used along with your car battery for a power station. A car battery is big enough to continuously charge stuff all the time with the solar cell replenishing it as sun output permits. You wouldn't have to monitor it or worry about dropouts and unless the solar cell was very powerful it could be left on it all during the outage and when it cannot keep up you can idle the vehicle for an hour or so to recharge the battery. The advantage is the solar cell would reduce need for gas usage and also the worry about dropouts and low solar output.
 

LEDrock

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Go to their website and look around.
https://sofirnlight.com/
Looks like the SC11 is 11.99 there with battery and $3 shipping but there is free shipping not sure how that works though I bought my sofirn off Ebay. I don't like the mode choices on the SC11 light at all and don't see any output ratings on it for the modes either.
I thought about getting an SP40 headlamp so I have 3 headlamps as I take one to work, another to use around the house and a spare one as the one I have at home is not a removeable headlamp that can be used as a flashlight if needed and trying to charge it using the built in charger is a pain the rubber plug is so hard to get out I have to use a pocket knife or a pair of retractors.

I looked on their site and couldn't find it (the Sofirn S11c. I also looked on Amazon and couldn't find it there either. Now I went to the Facebook group page to give you the link they had to the Amazon listing and I can't find that either. Maybe it was all just a dream.
 

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