Kerry, I think for a lot of applications the 1MHz switching noise will not be appearent in application. What interests me most about these are 3 things: Capacity, self discharge and chemical leakage. Since no manufacturer on the planet makes a leak proof alkaline battery (and Duracell is the worst for this as well as Costco) these batteries seem a very viable alternative. I have not researched the cost but if they are comparable to the Eveready Ultimate Lithium AA cells they are worth a look for me. These are the only cells I am currently using in my T&M equipment after alkalines destroyed the AA battery pack in my Fluke 289 DMM which cost me $80.00 for a new back. I would be interested to find out what the real self discharge looks like. It seems with NiMh cells and even some T&M gear (my Owon SDS6062 LiOn powered DSO an an example) are always dead when I need them. Thanks again for doing the review on these as I will be checking them out just as soon as I click the comment button. Sam W3OHM
I have 8 AA Eneloop batteries which were left for 6 years in satellite meter. Every one of them were discharged to 0V. None of them leaked, and all of them have been charged and have almost factory capacity. I don't remember any AA or AAA battery leaking that I've owned. In the past, NiCd button batteries leaked frequently.
@@brahmoone Long ago, I read that NiMH cells can leak, and I was skeptical, since my eneloops never did. Then everybody moved on to newer NiMH chemistries. I had high-capacity Energizers, Duracells, Rayovacs all getting grossly imbalanced and dying early -- and yes, they started leaking too. High capacity NiMH cells all seem to be a bad tradeoff. You're getting a little more capacity when young, but it's much less stable and more prone to leaking. Those old Eneloops from 16 years ago still work, and none have leaked. All but two out of dozens of newer legacy-brand high-capacity cells have failed, and a few have indeed leaked. The two that are left are barely able to run my wireless travel mouse for a few hours. At least that's my limited experience, grain of salt required.
good in depth review. I have two xtar cells and they were powering the device until the voltage dropped to zero. But the next day when I put them on the charger they would not charge anymore. Luckly after connecting them to a variable power supply set at 5V for a few seconds, with 450mA drawn current, they switched to charging mode again. You have to be careful not to wait too long after they get discharged because the lithium ion cell is likely to go very low and get damaged . Normally if you wait a few weeks the Li-ion cell should still be within limits, but not sure if the circuit will accept charging anymore, even if connected to a 5V PSU.
Why do I want to watch a video about testing a battery ? Because this is not just a battery ! 😉 As a beginner I have just learned sooooo much about these lithium batteries. 👏 Thank you so much for explaining the details in such a calm and informative style. I will never just pass on a 'simple battery review' again. Brilliant 😁
You covered under "switching noise" the problem I had trying to use Li-Ion rechargeable AA batteries in an AM/FM radio. If you take a li ion AA battery and place it close to the ferrite AM internal antenna of a radio, it completely blocks AM reception. How that was explained to me was the stepdown circuitry is working all the time whether the battery is being used or not. Your video is the first to explain this! Thank you. Great video.
You cant turn the circuit inside them off? Its like my small powerbank all over again! Kept making that almost audible noise and clicked every half second, It also was super loud on my SDR and AM radio. Opened it and soldered a switch into the circuit, but thats no option here... I was considering getting a couple of these, but thats not an option anymore. Thanks for warning me about that.
Nice review. Are there any issues with the batteries in series and parallel? Are the outputs of the regulator fully isolated from the inputs so you can use them together? Did you trace out the circuit? It would be nice to know how the circut is connected.
Hi Kerry, thank toy for a very interesting Video, you confirmed what I thought the construction was inside the cell. Here in Sweden I bought a similar product with the brand name XOXOPO, the AA cells are rated at 1850 mAhr together with a charger that is driven by a 5V USB cable. The instructions specifically say do not use the charger for any other cell type (such as NiMH). I am using the cells for driving an electric toothbrush, so the regulator noise does not bother its operation, at least I get 1.5 V which works great, as compared with when you use NiMN cells which have an output voltage of 1.2 and as a consequence runs slow. I have done capacity tests on these cells and at 200mA load they gave a performance of a little more than the rated 1850 mAhr. It will be interesting to see how long the cells last.
What would the intended use case for these be? Anything that runs from AA cells should work fine on NiMH cells unless it was very poorly designed. These have less capacity than NiMH cells while costing more than twice as much. They have a noisy output, I would imagine the self discharge rate is rather high because of the DC-DC converter, and they need a special charger.
The real difference between these and NiMH are likely only the constant output voltage and slightly lighter weight. I'm having trouble thinking of anything (other than maybe flashlights?) that would enjoy those benefits while also being OK with the noise and somewhat unpredictable shutoff. If it had another significant benefit (i.e. capacity, price, etc.) I think it could be a winner, but right now it seems pretty niche. I'd be curious if the noise caused any issues in something like a portable radio, too.
I have several motor-driven appliances (automated window blinds, kitchen garbage can lid, blood pressure machine, etc.) that are designed for AA cells and they ALL struggle with the decreased terminal voltage (1.2 volts) presented by NiMH cells.
@@setSCEtoAUX I've tried using rechargeable Li-ion AA batteries in AM/FM radios. They completely shutdown the AM band. I did an experiment a few days ago placing a Li ion AA in parallel with the ferrite antenna. Horrible noise and no signal.
Flashlights are the biggest thing. The 0.3v nominal voltage per cell makes a difference if the flashlight doesn't have voltage regulation, and most don't. I normally modify 4 cell devices to use 5 cells if they were designed for alkaline and I'm using Ni-MH. If it's a more sensitive device, I use a buck converter to drop the voltage to whatever it needs, maybe add a capacitor to smooth ripple.
I just received some AA and AAA usb type-c rechargeable both Rated for 5500mAh. I ran them down to 1.1v and measured the capacity of input energy. The AAA took 200mAh at 5V = 1000mWh and the AA took 675mAh at 5V = 3375mWh. The usealbe output capacity would be the mWh / 1.5V = 2250mAh for AA and 667mAh for AAA. I have asked how they calculate 5500mah without reply. Maybe the capacity is 5500 but only a partial amount is able to discharge. Testing 3 AAA in a small 9 LED flashlight caused damage to 2 flash lights. Flickering and burnt out LEDs while using these batteries. The switching noise was 50 to 100 mv and I suspect the flash lights received high voltage surges when the batteries were depleted. The safety circuitry is weak or non existent. Not sure if I trust using these batteries in my devices.
I'm affraid they included all 4-pack capacity in those 5500mAh. 😅 Or maybe summary capacity from brand-new to end-of-life usage 🤣 Also try to avoid using those batteries for devices that rely on internal resistance (IR) of cells and gradually lowering voltage - such as christmas LED lights, torches etc. These devices, especially cheap ones, dont have any corrent limiting resistors and rely solely on IR of batteries. This may be the reason, some LEDs failed. I think, these batteries can have their niche of usage with devices that need 1,5V like of alkaline, and operate poorly, when Ni-MH are used.
When used in series, is there less noise overall, or does the noise double? If you start will two fully charged cells in series, will they both reach full discharge around the same time? I would assume only one cell dropping to reduced voltage would not trigger a low battery signal. With the two cells disassembled, it would be interesting to track the voltage and current of each lithium cell through a discharge cycle. I suspect these cells will be used in series more often than not. When the one cell expires, does it allow current to flow or does it go open circuit? The potential problem is the continued battery output is limited by the weakest cell, shutting down more quickly than a standard rechargeable would.
Like you said, when connected in series, it's only going to last as long as the weakest one. And the cutoff would be abrupt compared to your typical cells.
excellent excellent video.. been waiting for an in depth explanation of these batteries.. if ever possible, please do a comparison.. 1.5v to 1.5v and 1.5v to 1.2v.. thanks again..
@Kerry Wong, I have a challenge for you :) First, thank you for this fabulous video. I learned quite a lot about the 1.4V Li-Ion cell. My challenge: How can I see how full a 1.5V Li-Ion battery is charged, since there is no voltage drop until the last 5% capacity, hence a standard Ni-Mh battery tester will show a full battery because of the consistent voltage even though it might be drained down to 20% of it's capacity? (final voltage drop to indicate the empty cell is at the last roughly 5% if I got it right) I thought about measuring the internal resistance in Ohm because I believe it would become larger as the cell discharges, but the chip inside the cell might distort the result. Can you recommend a special test device or workaround? Thanks a bunch again and keep up your great videos.
It won't be easy as the DC-DC converter will try to maintain the 1.5V output. In theory, you should be able to infer by drawing close to the maximum allowed current. As when the internal resistance of the lithium ion cell increases, it wouldn't be able to sustain the high current draw without significant voltage drop and the DC-DC converter would cut out at smaller current.
@@KerryWongBlog thanks a lot for sharing that approach. As I am a home user with little equipment, I am afraid I have to wait till the market offers home user testers. On the other hand, as there is no home user testing device yet, is there any chance you create a video how you would test the current charging status of a 1.5V Li-Ion if this is interesting to more users?
@@sklepaAt a guess is should be comparable with any Lithium Ion cell of the same size. Low current Lithium cell that is, similar in performance to a button cell. Since it can support 2 Amps maximum AFTER the STEP DOWN from 4.2 to 1.5 V its maximum native current should be in the vicinity of 700 mAmps.
I tried NiZn but the charger would not work. I had defective cells, a defective charger or possibly both. I just returned them. This shows that some alkaline alternatives are mediocre! Not only that but the two more common rechargeable chemistries have a voltage of 1.2 volts. That can put a huge limit on the number of things they work in. I had a digital camera that uses AA cells so I would know a bit about the abysmal life of nickel cadmium and the somewhat better yet still mediocre nickel hydride.
these seem to behave exactly like a random chinese brand I bought few years ago... it was solid 1.5 volts out until near end then it stepped down to i think 1.0 volts... used them for a long time in a wireless keyboard i had... one of them them failed in a way that it wouldnt charge anymore.
Whaaaaaat?! Really? They use ordinary Shottky diode instead of some kind of mosfet-operating protection against reverse polarity? that could be the source of this 75 degree heat, when drawing 2,5A of power... I hope, they improve this converter, to be more efficient. Also, deeper testing would be nice, in that area. Also, I would love to see the battery voltage, to be gradually falling from 1,5 to 1V in last 30% of energy state, instead of that one-step fall, which may cause some operated digital instruments to crash before they notice user of low battery.
wowww now you have let the cat out of the bag, the converters will be the failure point just like the bms is on the large lithion 100ahr batteries leaving a person with a dead battery ...Its a given, the electronics can NOT hold the constant cycle of In out voltage /current , so sad stick with nimh no internal parts circuits etc .
I find the idea good, but what you mention about current draw/ temperature could be a problem with combustion.I would wonder if the battery could be used in outside wireless weather stations.
@@johnwest7993 because it's Li or the voltage configuration? I don't remember hearing about low temp problems with Li. Could you please explain or should I just "see the books".I wasn't thinking of charging them in place. Oh heavens, my station has no way to recharge in place. I believe I see your point now, thanks.
@@jdmccorful Most lithium ion cells can be damaged if charged below 0°C. You can usually get away with a very slow trickle charge though. They would work if you are not charging them outside, but the DC-DC converter in these cells will probably drain them rather quickly. 1.5V lithium primary cells would be a much better choice for a low powered device like a weather station sensor since they can handle below freezing temperatures well.
@@rocketman221projects I hear what you are saying. I have always used the Energizers Li batteries in my station, but in the past year they have gotten so expensive and I hate disposing. Initial expense ok for these rechargable and I would swap and recharge in stable 72 degree home.Thanks for your time.
Kerry, I think for a lot of applications the 1MHz switching noise will not be appearent in application. What interests me most about these are 3 things: Capacity, self discharge and chemical leakage. Since no manufacturer on the planet makes a leak proof alkaline battery (and Duracell is the worst for this as well as Costco) these batteries seem a very viable alternative. I have not researched the cost but if they are comparable to the Eveready Ultimate Lithium AA cells they are worth a look for me. These are the only cells I am currently using in my T&M equipment after alkalines destroyed the AA battery pack in my Fluke 289 DMM which cost me $80.00 for a new back. I would be interested to find out what the real self discharge looks like. It seems with NiMh cells and even some T&M gear (my Owon SDS6062 LiOn powered DSO an an example) are always dead when I need them. Thanks again for doing the review on these as I will be checking them out just as soon as I click the comment button. Sam W3OHM
Neither NiMH or non-rechargeable Lithium AA leaks..
I have 8 AA Eneloop batteries which were left for 6 years in satellite meter. Every one of them were discharged to 0V. None of them leaked, and all of them have been charged and have almost factory capacity. I don't remember any AA or AAA battery leaking that I've owned. In the past, NiCd button batteries leaked frequently.
@@brahmoone Long ago, I read that NiMH cells can leak, and I was skeptical, since my eneloops never did. Then everybody moved on to newer NiMH chemistries. I had high-capacity Energizers, Duracells, Rayovacs all getting grossly imbalanced and dying early -- and yes, they started leaking too. High capacity NiMH cells all seem to be a bad tradeoff. You're getting a little more capacity when young, but it's much less stable and more prone to leaking. Those old Eneloops from 16 years ago still work, and none have leaked. All but two out of dozens of newer legacy-brand high-capacity cells have failed, and a few have indeed leaked. The two that are left are barely able to run my wireless travel mouse for a few hours.
At least that's my limited experience, grain of salt required.
good in depth review. I have two xtar cells and they were powering the device until the voltage dropped to zero. But the next day when I put them on the charger they would not charge anymore. Luckly after connecting them to a variable power supply set at 5V for a few seconds, with 450mA drawn current, they switched to charging mode again. You have to be careful not to wait too long after they get discharged because the lithium ion cell is likely to go very low and get damaged . Normally if you wait a few weeks the Li-ion cell should still be within limits, but not sure if the circuit will accept charging anymore, even if connected to a 5V PSU.
Why do I want to watch a video about testing a battery ?
Because this is not just a battery ! 😉
As a beginner I have just learned sooooo much about these lithium batteries. 👏
Thank you so much for explaining the details in such a calm and informative style.
I will never just pass on a 'simple battery review' again.
Brilliant 😁
You covered under "switching noise" the problem I had trying to use Li-Ion rechargeable AA batteries in an AM/FM radio. If you take a li ion AA battery and place it close to the ferrite AM internal antenna of a radio, it completely blocks AM reception. How that was explained to me was the stepdown circuitry is working all the time whether the battery is being used or not. Your video is the first to explain this! Thank you. Great video.
You cant turn the circuit inside them off?
Its like my small powerbank all over again! Kept making that almost audible noise and clicked every half second, It also was super loud on my SDR and AM radio.
Opened it and soldered a switch into the circuit, but thats no option here...
I was considering getting a couple of these, but thats not an option anymore. Thanks for warning me about that.
It would be nice to have measurements of the quiescent current of the regulator under no load and also under light loads to get an idea of the losses.
full range efficiency plot would be awesome
Thanks Kerry. Interesting cells. But obviously RF noisy, and expensive, suitable only for very limited applications.
Thank you for so much useful information! I wish all batteries came with a stat sheet of all the info you gave in this video. Great work.
Great review, and an interesting cell....cheers.
Nice review. Are there any issues with the batteries in series and parallel? Are the outputs of the regulator fully isolated from the inputs so you can use them together? Did you trace out the circuit? It would be nice to know how the circut is connected.
Good job, you answered all my questions. Thanks.
Hi Kerry, thank toy for a very interesting Video, you confirmed what I thought the construction was inside the cell. Here in Sweden I bought a similar product with the brand name XOXOPO, the AA cells are rated at 1850 mAhr together with a charger that is driven by a 5V USB cable. The instructions specifically say do not use the charger for any other cell type (such as NiMH). I am using the cells for driving an electric toothbrush, so the regulator noise does not bother its operation, at least I get 1.5 V which works great, as compared with when you use NiMN cells which have an output voltage of 1.2 and as a consequence runs slow. I have done capacity tests on these cells and at 200mA load they gave a performance of a little more than the rated 1850 mAhr. It will be interesting to see how long the cells last.
Thanks for the video. Can a similar analysis be done for Eneloop Lithium ION Batteries?
What would the intended use case for these be? Anything that runs from AA cells should work fine on NiMH cells unless it was very poorly designed.
These have less capacity than NiMH cells while costing more than twice as much. They have a noisy output, I would imagine the self discharge rate is rather high because of the DC-DC converter, and they need a special charger.
The real difference between these and NiMH are likely only the constant output voltage and slightly lighter weight. I'm having trouble thinking of anything (other than maybe flashlights?) that would enjoy those benefits while also being OK with the noise and somewhat unpredictable shutoff. If it had another significant benefit (i.e. capacity, price, etc.) I think it could be a winner, but right now it seems pretty niche. I'd be curious if the noise caused any issues in something like a portable radio, too.
I have several motor-driven appliances (automated window blinds, kitchen garbage can lid, blood pressure machine, etc.) that are designed for AA cells and they ALL struggle with the decreased terminal voltage (1.2 volts) presented by NiMH cells.
@@setSCEtoAUX I've tried using rechargeable Li-ion AA batteries in AM/FM radios. They completely shutdown the AM band. I did an experiment a few days ago placing a Li ion AA in parallel with the ferrite antenna. Horrible noise and no signal.
Flashlights are the biggest thing. The 0.3v nominal voltage per cell makes a difference if the flashlight doesn't have voltage regulation, and most don't.
I normally modify 4 cell devices to use 5 cells if they were designed for alkaline and I'm using Ni-MH. If it's a more sensitive device, I use a buck converter to drop the voltage to whatever it needs, maybe add a capacitor to smooth ripple.
@@Pantology_Enthusiastthe best flashlishts runs on 18650
I just received some AA and AAA usb type-c rechargeable both Rated for 5500mAh. I ran them down to 1.1v and measured the capacity of input energy. The AAA took 200mAh at 5V = 1000mWh and the AA took 675mAh at 5V = 3375mWh. The usealbe output capacity would be the mWh / 1.5V = 2250mAh for AA and 667mAh for AAA. I have asked how they calculate 5500mah without reply. Maybe the capacity is 5500 but only a partial amount is able to discharge. Testing 3 AAA in a small 9 LED flashlight caused damage to 2 flash lights. Flickering and burnt out LEDs while using these batteries. The switching noise was 50 to 100 mv and I suspect the flash lights received high voltage surges when the batteries were depleted. The safety circuitry is weak or non existent.
Not sure if I trust using these batteries in my devices.
I'm affraid they included all 4-pack capacity in those 5500mAh. 😅 Or maybe summary capacity from brand-new to end-of-life usage 🤣
Also try to avoid using those batteries for devices that rely on internal resistance (IR) of cells and gradually lowering voltage - such as christmas LED lights, torches etc. These devices, especially cheap ones, dont have any corrent limiting resistors and rely solely on IR of batteries. This may be the reason, some LEDs failed. I think, these batteries can have their niche of usage with devices that need 1,5V like of alkaline, and operate poorly, when Ni-MH are used.
You do realize that they are using Chinese mAh in their documentation?....
When used in series, is there less noise overall, or does the noise double? If you start will two fully charged cells in series, will they both reach full discharge around the same time? I would assume only one cell dropping to reduced voltage would not trigger a low battery signal. With the two cells disassembled, it would be interesting to track the voltage and current of each lithium cell through a discharge cycle. I suspect these cells will be used in series more often than not. When the one cell expires, does it allow current to flow or does it go open circuit? The potential problem is the continued battery output is limited by the weakest cell, shutting down more quickly than a standard rechargeable would.
Like you said, when connected in series, it's only going to last as long as the weakest one. And the cutoff would be abrupt compared to your typical cells.
Thanks for explaining this. I was wondering how they work.
This article was mentioned on an Elecraft listserv about batteries.
Please connect spectrum analyser for RF noise analysts
Nice review, can i know is NICD 1.2v batteries do have noise like this lithium 1.5 battery?
excellent excellent video.. been waiting for an in depth explanation of these batteries.. if ever possible, please do a comparison.. 1.5v to 1.5v and 1.5v to 1.2v.. thanks again..
@Kerry Wong, I have a challenge for you :)
First, thank you for this fabulous video. I learned quite a lot about the 1.4V Li-Ion cell.
My challenge:
How can I see how full a 1.5V Li-Ion battery is charged, since there is no voltage drop until the last 5% capacity, hence a standard Ni-Mh battery tester will show a full battery because of the consistent voltage even though it might be drained down to 20% of it's capacity?
(final voltage drop to indicate the empty cell is at the last roughly 5% if I got it right)
I thought about measuring the internal resistance in Ohm because I believe it would become larger as the cell discharges, but the chip inside the cell might distort the result.
Can you recommend a special test device or workaround?
Thanks a bunch again and keep up your great videos.
It won't be easy as the DC-DC converter will try to maintain the 1.5V output. In theory, you should be able to infer by drawing close to the maximum allowed current. As when the internal resistance of the lithium ion cell increases, it wouldn't be able to sustain the high current draw without significant voltage drop and the DC-DC converter would cut out at smaller current.
@@KerryWongBlog thanks a lot for sharing that approach. As I am a home user with little equipment, I am afraid I have to wait till the market offers home user testers.
On the other hand, as there is no home user testing device yet, is there any chance you create a video how you would test the current charging status of a 1.5V Li-Ion if this is interesting to more users?
Very well done. Over my head a bit, but I did see understand quite a bit.
It would be nice if the DC voltage conversion would work both ways, so you can charge them with a regular 1.5 volt NiMH battery charger.
That would make it way more complicated and would probably need more space.
Does the same charging mode apply to lithium battery with usb port as well?
Very thorough. Wonderful.
can i use a regular nimh AA/AAA battery charger with this xstar lithium battery ?
Have you measured bare cell capacity? It would be interesting how much it has.
16:45 Measured battery capacity
I mean without dcdc conveter. From 4.2V to lets say to 2.8V
@@sklepaAt a guess is should be comparable with any Lithium Ion cell of the same size. Low current Lithium cell that is, similar in performance to a button cell. Since it can support 2 Amps maximum AFTER the STEP DOWN from 4.2 to 1.5 V its maximum native current should be in the vicinity of 700 mAmps.
@@blg53 yep, i know but was curious if Kerry measured some exact numbers 👍
I should be able to charge this with my XTAR VC4 charger then? Since it's just basically a 18650 type battery but in a AA size format
I don't think so. The VC4 is for charging NiMH or Li-ion cells. These require 5 volt charging.
@@AdamHelbThe video does show the charging starts at around 3.7v I think
@@mohgujai I still think the VC4 does not know how to charge these cells properly. The charger for these XTAR cells is really inexpensive.
@@AdamHelb it's not about $ it's about minimising waste, if the charger is still good I want to reuse it
Does this mean the Xtar charger isn't compatible for 1.5v li-ion batteries from other brands?
18 uA standby is very usefully information
Thank you
I tried NiZn but the charger would not work. I had defective cells, a defective charger or possibly both. I just returned them. This shows that some alkaline alternatives are mediocre! Not only that but the two more common rechargeable chemistries have a voltage of 1.2 volts. That can put a huge limit on the number of things they work in. I had a digital camera that uses AA cells so I would know a bit about the abysmal life of nickel cadmium and the somewhat better yet still mediocre nickel hydride.
these seem to behave exactly like a random chinese brand I bought few years ago... it was solid 1.5 volts out until near end then it stepped down to i think 1.0 volts... used them for a long time in a wireless keyboard i had... one of them them failed in a way that it wouldnt charge anymore.
Goooood. I did buy 3 ....
Whaaaaaat?! Really? They use ordinary Shottky diode instead of some kind of mosfet-operating protection against reverse polarity? that could be the source of this 75 degree heat, when drawing 2,5A of power... I hope, they improve this converter, to be more efficient. Also, deeper testing would be nice, in that area. Also, I would love to see the battery voltage, to be gradually falling from 1,5 to 1V in last 30% of energy state, instead of that one-step fall, which may cause some operated digital instruments to crash before they notice user of low battery.
Great review--very thorough.
Hello, do you still have the source code for this project?
ua-cam.com/video/XzmNSrF72LI/v-deo.html
I bought Lazada 1.5v rechargeable battery 6 month after leaking very disappointed
wowww now you have let the cat out of the bag, the converters will be the failure point just like the bms is on the large lithion 100ahr batteries leaving a person with a dead battery ...Its a given, the electronics can NOT hold the constant cycle of In out voltage /current , so sad stick with nimh no internal parts circuits etc .
I find the idea good, but what you mention about current draw/ temperature could be a problem with combustion.I would wonder if the battery could be used in outside wireless weather stations.
Not if you live anywhere it freezes if your weather station has PV recharging. You do not want to try to charge those cells below 0c.
@@johnwest7993 because it's Li or the voltage configuration? I don't remember hearing about low temp problems with Li. Could you please explain or should I just "see the books".I wasn't thinking of charging them in place. Oh heavens, my station has no way to recharge in place. I believe I see your point now, thanks.
@@jdmccorful Most lithium ion cells can be damaged if charged below 0°C. You can usually get away with a very slow trickle charge though.
They would work if you are not charging them outside, but the DC-DC converter in these cells will probably drain them rather quickly. 1.5V lithium primary cells would be a much better choice for a low powered device like a weather station sensor since they can handle below freezing temperatures well.
@@rocketman221projects I hear what you are saying. I have always used the Energizers Li batteries in my station, but in the past year they have gotten so expensive and I hate disposing. Initial expense ok for these rechargable and I would swap and recharge in stable 72 degree home.Thanks for your time.
Great review, and an interesting cell....cheers.