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Make 18650s long again

danalog
By danalog
in Hobby Electronics
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Last night I had the incredible realization I can get free 18650s from old laptop batteries and now I have 42 18650 cells to do ... something? with.

However they're all the slightly shorter type with the wider, flatter positive top due to being spot welded, so they only fit in like 60% of devices.

PXL_20250706_163803385.thumb.jpg.d413d15b950b5507763cb033644657ad.jpg

Any suggestions of how to make these fit in devices that need that smaller tip? 

I was thinking of spot welding a BB or a tiny spring to the top but there is probably a much better solution. It's my first time working with any lithium batts so any advice would be greatly appreciated!

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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1 hour ago, danalog said:

Last night I had the incredible realization I can get free 18650s from old laptop batteries and now I have 42 18650 cells to do ... something? with.

However they're all the slightly shorter type with the wider, flatter positive top due to being spot welded, so they only fit in like 60% of devices.

PXL_20250706_163803385.thumb.jpg.d413d15b950b5507763cb033644657ad.jpg

Any suggestions of how to make these fit in devices that need that smaller tip? 

I was thinking of spot welding a BB or a tiny spring to the top but there is probably a much better solution. It's my first time working with any lithium batts so any advice would be greatly appreciated!

you might be able to use a little aluminum foil like you can to put AAA batteries in things that use AA

proud owner of a AMD Athlon 64 cpu

PSU tier list: https://docs.google.com/spreadsheets/d/1akCHL7Vhzk_EhrpIGkz8zTEvYfLDcaSpZRB6Xt6JWkc/edit?gid=1973454078#gid=1973454078

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just for reference, there's two "shapes" 18650 cells come in: the flat top commonly used in battery packs (because it's more space efficient), and the button top for use in devices with battery compartiments.

 

an important thing to note here is that the flat top cells generally arent protected, and that ridge sticking out around the positive side is actually the negative side, so it's very easy to short it out if you dont protect it, and the cell has no protection against overcharge or overdischarge.

 

i'd say cut a ring to protect the cell out of electrical tape or something like that, and then use something metal to act as a spacer, depending on what you have available.

 

you really shouldnt use bare cells in any application where they arent connected trough a BMS though, and there are battery holders that'll gladly hold flat top cells if you're about to make a custom pack.

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54 minutes ago, manikyath said:

just for reference, there's two "shapes" 18650 cells come in: the flat top commonly used in battery packs (because it's more space efficient), and the button top for use in devices with battery compartiments.

 

an important thing to note here is that the flat top cells generally arent protected, and that ridge sticking out around the positive side is actually the negative side, so it's very easy to short it out if you dont protect it, and the cell has no protection against overcharge or overdischarge.

Yup, figured that out pretty quickly while removing these still-charged cells from the laptop batteries. I'm building a circuit with a protection chip for charging the flat top ones. 

55 minutes ago, manikyath said:

you really shouldnt use bare cells in any application where they arent connected trough a BMS though, and there are battery holders that'll gladly hold flat top cells if you're about to make a custom pack.

A few of these are going in USB power banks. I'll look into a BMS but my hope was that I wouldn't need a controller on the discharge side - I'm planning to use these simply as more compact replacements for three-AA packs in some of my custom built little gizmos. No crazy high discharge current. 

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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What you can do, in some cases is bend the spring clip that holds the battery tight against the other end, at least for the flat ends batteries

 

To find if this will wok, insert the battery and see if you can bed the spring clip out enough to make good contact,not always doable due the gap.

 

An no matter what you do, if possible leave the battery in sight and easy to access, so you can feel if it's getting warmer after 10 minutes or so. This way if it is getting warmer STOP and unplug. Then either try another battery or place a wad of aluminum foil against the spring and try again. 

Still with the cover off, check again after 10 or so minutes.

 

It's better to be safe than  endanger yourself and whatever you're using the batteries in. 

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I know this is far from the ideal solution, but I usually just solder a nice big blob on the tip. You have to be careful not to melt anything inside the cell. You can use a damp rag right after the solder solidifies to cool the cell back down.

 

The positive end of these is where the roll crimp seals them shut, and so the whole can of the cell including around the end is negative.

 

Just be careful! You want a really grunty soldering iron to get in and out quick.

 

5 minutes ago, danalog said:

Yup, figured that out pretty quickly while removing these still-charged cells from the laptop batteries. I'm building a circuit with a protection chip for charging the flat top ones. 

A few of these are going in USB power banks. I'll look into a BMS but my hope was that I wouldn't need a controller on the discharge side - I'm planning to use these simply as more compact replacements for three-AA packs in some of my custom built little gizmos. No crazy high discharge current. 

 

If you're using them in USB power banks, they've got cell protection as part of their circuitry.

 

If you're using them in retrofit projects, something like these would work, they have protection and a charger on one board, the load connects to the board and disconnects if the cell drops too low:

https://www.amazon.com/dp/B00LTQU2RK/

 

However, if you're using multiple cells in parallel in any application, make sure they're at the same voltage when joined together

Donate your unused computer resources for cancer and other research. For Zinsey ❤

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2 minutes ago, danalog said:

A few of these are going in USB power banks.

as long as the power banks are designed to work with lithium cells (aka you're swapping out other lithium cells for these) the circuitry probably has an integrated BMS good enough to at least prevent critical damage.

3 minutes ago, danalog said:

I'm planning to use these simply as more compact replacements for three-AA packs in some of my custom built little gizmos.

look into buying some single-cell BMS modules, they can be had for dirt cheap as long as you're not looking at very high current scenarios. the single cell ones i have laying around do 2A and are €1 a piece (and i'm WAY overpaying for them for the sake of fast delivery times)

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#BringTheNippleBack ??

22 hours ago, iamdarkyoshi said:

I know this is far from the ideal solution, but I usually just solder a nice big blob on the tip. You have to be careful not to melt anything inside the cell. You can use a damp rag right after the solder solidifies to cool the cell back down.

 

The positive end of these is where the roll crimp seals them shut, and so the whole can of the cell including around the end is negative.

 

Just be careful! You want a really grunty soldering iron to get in and out quick.

 

 

If you're using them in USB power banks, they've got cell protection as part of their circuitry.

 

If you're using them in retrofit projects, something like these would work, they have protection and a charger on one board, the load connects to the board and disconnects if the cell drops too low:

https://www.amazon.com/dp/B00LTQU2RK/

 

However, if you're using multiple cells in parallel in any application, make sure they're at the same voltage when joined together

I've done this, but inverted the process to the device. I dripped solder onto the device's positive contact pad and made a easy raised surface to take up the gap. I figured the device was less heat sensitive than the battery. Now the device can use both styles bc the spring for the negative end has enough play in it to work for both lengths without damage or deforming. I have also just stretched the negative spring out some to make good contact if the positive pad has an existing raised surface.

Dreaming of the day when my brain cell doesn't betray me.

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5 minutes ago, CasualExtremist said:

#BringTheNippleBack ??

I've done this, but inverted the process to the device. I dripped solder onto the device's positive contact pad and made a easy raised surface to take up the gap. I figured the device was less heat sensitive than the battery. Now the device can use both styles bc the spring for the negative end has enough play in it to work for both lengths without damage or deforming. I have also just stretched the negative spring out some to make good contact if the positive pad has an existing raised surface.

That's a very smart option. I worried about soldering between the positive and negative on the battery and not catching it till it was too late..

What the horse considers play, the monkey considers business...

But to Tom, it's all foolery. 

 

 

 

 

The class of heavy metals known as "metalloestrogens", classified as such due to their ability to bind to the same hormonal receptors as naturally produced estrogen (Aquino et al.), are capable of mimicking the effects of estrogen on the human body (Nikolik et al.). Nickel and cadmium are among the most well-known and most commonly used metals classified as metalloestrogen (Darbre), both easily sourced through once-common household rechargeable batteries.

Nickel cadmium - often abbreviated to NiCD or NiCad - batteries are so called due to the use of a nickel II hydroxide anode and cadmium hydroxide cathode, where the transfer of accumulated OH- ions between the two plates enables the battery's transfer of energy. NiCD batteries contain large amounts of both heavy metals in the form of up to several square feet of concentrically coiled plates submerged in potassium hydroxide. Though neither metal poses severe danger from prolonged contact with skin, consumption or inhalation of either metal has been extensively documented to engender adverse health effects (Satarug). 

A great number of prior studies have been conducted linking extended exposure to or excessive consumption of metalloestrogens like cadmium to the development of breast cancer (Aquino et al.) - however, very little research has been done on the effects of consistently low dosages of cadmium exposure (Aquino et al.). Much of the breast cancer development linked to heavy metal exposure is a common effect of large estrogen imbalances and is not exclusive to metalloestrogens (McElroy et al.). Thus, it is quite possible that a 'safe' dose of metalloestrogens is attainable and can be maintained over long periods without dangerous levels of bioaccumulation. 

Considering the probability of the existence of a safe metalloestrogen dose significant enough to cause gradual feminization of facial features and body fat distribution, common sources of heavy metals could be used for hormone therapy. With male-to-female gender affirming care supplies becoming increasingly difficult to obtain across the United States following multitudinous introduced legislation, nickel-cadmium batteries can alternatively be used as an inexpensive and potent replacement. 

 

Works Cited

      Aquino NB, Sevigny MB, Sabangan J, Louie MC. The role of cadmium and nickel in estrogen receptor signaling and breast cancer: metalloestrogens or not? J Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2012;30(3):189-224. doi: 10.1080/10590501.2012.705159. PMID: 22970719; PMCID: PMC3476837.

      Rollerova, E., Urbancikova, N. Intracellular estrogen receptors, their characterization and function (Review). https://www.sav.sk/journals/endo/full/er0400f.pdf.

      Nikolic J, Sokolovic D. Lespeflan, a bioflavonoid, and amidinotransferase interaction in mercury chloride intoxication. Ren Fail. 2004 Nov;26(6):607-11. doi: 10.1081/jdi-200037149. PMID: 15600250.

      Darbre PD. Metalloestrogens: an emerging class of inorganic xenoestrogens with potential to add to the oestrogenic burden of the human breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. doi: 10.1002/jat.1135. PMID: 16489580.

      Satarug S, Garrett SH, Sens MA, Sens DA. Cadmium, environmental exposure, and health outcomes. Environ Health Perspect. 2010 Feb;118(2):182-90. doi: 10.1289/ehp.0901234. PMID: 20123617; PMCID: PMC2831915.

      McElroy JA, Shafer MM, Trentham-Dietz A, Hampton JM, Newcomb PA. Cadmium exposure and breast cancer risk. J Natl Cancer Inst. 2006 Jun 21;98(12):869-73. doi: 10.1093/jnci/djj233. PMID: 16788160.

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11 minutes ago, CasualExtremist said:

#BringTheNippleBack ??

Oh shit, I thought I deleted that hashtag after thinking of something actually useful to say. I guess Imma stick with it now that danalog has it permanently archived as a quote too.💀🤣

Dreaming of the day when my brain cell doesn't betray me.

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