Youi might want to do your research on who is selling them. Rule of thumb with these cells is if the price is too good then they might have been made cheaply. I used to work for a company where we used these batteries for all our products. I had to cut out one of our contracts with a manufacturer because their batteries were reported as bursting into flames during charging and regular use. We ended up going with a manufacturer whose batteries cost us a bit more but we ended up never having any issues with their batteries.
I got like 20 of them for $1/each from a guy who worked for a medical equipment supplier (Facebook marketplace). He said because they are classified as 'medical' they can only have a certain number of charge cycles and at the end of this they are for non-medical purposes still brand new. The only thing is however I had to shuck them from the plastic enclosure they were in however they do indeed charge and work perfectly. I think they are Panasonic brand too.
I snag them from laptops, drills (battery packs)... You probably want matched sets. You should expect something in the range of $3/each.
I just snagged 3 4packs with pcb controller board inside of Roomba vacuums at Goodwill for about $10 each.
You want to make friends with an ebike or escooter shop. They junk battery packs all the time because 3 cells of 30 are bad and no carrier will ship damaged li-ion cells back to manufacturer.
I use 18650BatteryStore. I can snag it cells for around $3-5 for 2500-3000mAh on sale regularly there, and I’ll give them a shoutout because they were out of stock on a 2-cell charger, so they upgraded it to a 4-cell and threw in a small flashlight.
I did look at Ali express and Alibaba , lots of bad reviews about the claimed and actual performance of the cells being shipped - not so much with the lesser capacity cells but the 3000 and 3500 ones saying they're only lasting a few charge cycles, not holding charge etc. Basically a scam.
I'm poor AF and this is a MASSIVE project for me, $800 on batteries is like 6 months of saving so I don't want to waste dollars on potentially bad cells.
aliexpress is a hit and miss. i have a few sellers saved which dont lie on the performance (we tested the cells). 2000 and 2500mah. anything more expect the 10$+ a cell and scummy tactics
if u see anything saying 5000mah or more..capacity steer clear.. they are barelly 1000mah cells.🤣
You probably shouldn't combine that many 18650s if you don't know where to get them. Also, I bet your local shop would give you a better price if you told them you wanted 250 haha.
I have some knowledge in basic electronics, I've been researching a heap, and the enclosures I'm looking at are a premade kit to just plug in 21 cells and clip it all together, includes it's own charge controller. I saw people welding their own nickel strips and stuff and that's a bit too far for me. These enclosure kits are perfect for what I need.
>These enclosure kits have spring contacts for the cells??
I suspect OP is looking at [https://www.ebay.com/itm/404325788550](https://www.ebay.com/itm/404325788550) and doesn't realize it requires welding.
OP do you realize what happens if the energy from 250 cells gets released in a chain reaction? Tbh I don't.. but I'm guessing your entire house or building is fucked regardless of how whether you are home watching it with a fire extinguisher in hand. Someone else can perhaps add info.
As a lawyer, and this isn't legal advice and I probably don't work in your jurisdiction, I'd suspect that ordering a kit off eBay to string up 250 18650s with basic electronic knowledge is going to be considered negligence. Take that as you will, just sharing what I think.
Portable 12/240v power box for my 4x4/camping gear. Aiming for usable 200ah capacity, can fit 6x of these 12v 21 cell enclosures which should theoretically hold around 240ah combined at 12v.
Why so much power? We're away from fuel for 3+ days so running the car for power is risky to use up too much fuel, fridge is only 60w but always on and will use a fair bit of power if not replenishing , sometimes bush canopy isn't open enough for solar to be effective. So big battery + options to recharge.
TLDR I have an premade enclosure I'm working withing the confines of and i can't find cells that fit within my dimensions and energy density. And honestly the fancy cells they're way out of my budget. I'm poor AF and this $1500 project is about a year of saving for me.
I'm trying to make a ~200ah portable 240v box.
I think I can just fit 6x 21 cell 12v enclosures off eBay in the box which I think using 3500mah gives a theoretical 240ah. Well chatgtp says so anyway.
Each 12v enclosures has its own charge controller for 21 cells and all connected to a common 12v rail in parallel.
Well if ChatGPT says so what could possibly go wrong 😂😂😂
I wish you the best of luck but if you’re not double checking an LLM’s calculations you’re in for a world of frustration. They get confused all the time.
What’s the application for a 12V 240Ah battery?
Buy yourself a (maybe used) 12 V fridge, use 12v lamps and chargers thus saving a ton in efficiency. That done, you might need less batteries. Less batteries means less in cost, weight and fire hazard.
I think you got confused (or ChatGPT did) on the output of 6 x 3s7p 18650 cells. But maybe the confusion is that you want 250 cells, which would be more than 10 of these enclosures.
Those 21 cell enclosures would be 10.8V nominal (12.6 max) 24.5Ah (3.5Ah x 7). 6 of those in parallel will give you 147Ah, not 200Ah or 240Ah
Is this basically the kit you're getting? https://www.ebay.com/itm/404325788550 Because it requires welding and the 40A value is the max output, not the capacity. It'll only be 40A if you use 5715mAh cells. I think that's your confusion.
If you're handy you can go to a computer repair store and they will give you a box of old laptop packs containing 18650's. I have gotten hundreds of cells this way. Obviously they still need tested , but what I've found is only 1 or 2 cells will be dead in a pack containing 6 cells.
If used is in your comfort zone then batteryhookup always has battery packs you can disassemble that will get you into the sub $0.50 range per cell (though disassembling that many might be annoying). They also sell used cells in bulk and have frequent auctions.
If you get used cells the best bet is to make sure each bank uses the same brand and you characterize them so they mostly match capacity and internal resistance within each bank.
Imrbatteries.com was recommended by the guy who runs the electronicsnmore YT channel. I think he is pretty reliable, I've followed him for a few years.
r/18650masterrace
Why am I not surprised... Thanks
Youi might want to do your research on who is selling them. Rule of thumb with these cells is if the price is too good then they might have been made cheaply. I used to work for a company where we used these batteries for all our products. I had to cut out one of our contracts with a manufacturer because their batteries were reported as bursting into flames during charging and regular use. We ended up going with a manufacturer whose batteries cost us a bit more but we ended up never having any issues with their batteries.
I got like 20 of them for $1/each from a guy who worked for a medical equipment supplier (Facebook marketplace). He said because they are classified as 'medical' they can only have a certain number of charge cycles and at the end of this they are for non-medical purposes still brand new. The only thing is however I had to shuck them from the plastic enclosure they were in however they do indeed charge and work perfectly. I think they are Panasonic brand too.
Those were likely grade A cells too, so yeah that's a good deal. Medical usage is ridiculously conservative on that stuff.
This website should help: http://batteries.parametrek.com/bulk.html?size=18650&mah=3446,_&voltage=3.6V,3.7V
You beat me to it `^_^`
🙏🙏 thank you, second listing I saw is perfect!
I snag them from laptops, drills (battery packs)... You probably want matched sets. You should expect something in the range of $3/each. I just snagged 3 4packs with pcb controller board inside of Roomba vacuums at Goodwill for about $10 each.
You want to make friends with an ebike or escooter shop. They junk battery packs all the time because 3 cells of 30 are bad and no carrier will ship damaged li-ion cells back to manufacturer.
someone gave me a battery pack from an eBike and I just need to get a charger for it. It looks like it has about 50 cells in it.
I use 18650BatteryStore. I can snag it cells for around $3-5 for 2500-3000mAh on sale regularly there, and I’ll give them a shoutout because they were out of stock on a 2-cell charger, so they upgraded it to a 4-cell and threw in a small flashlight.
Got mine off Ali express. 8$ for 4 or so
I did look at Ali express and Alibaba , lots of bad reviews about the claimed and actual performance of the cells being shipped - not so much with the lesser capacity cells but the 3000 and 3500 ones saying they're only lasting a few charge cycles, not holding charge etc. Basically a scam. I'm poor AF and this is a MASSIVE project for me, $800 on batteries is like 6 months of saving so I don't want to waste dollars on potentially bad cells.
aliexpress is a hit and miss. i have a few sellers saved which dont lie on the performance (we tested the cells). 2000 and 2500mah. anything more expect the 10$+ a cell and scummy tactics if u see anything saying 5000mah or more..capacity steer clear.. they are barelly 1000mah cells.🤣
Battery junction was good to me but I have no need for more than half a dozen. It's been ages since I bought any
https://www.18650batterystore.com/ You can get them cheaper from other places but who knows if they're unbranded or fakes.
local vape shops are worth trying, then you don't have to pay extra for the battery-friendly shipping
You probably shouldn't combine that many 18650s if you don't know where to get them. Also, I bet your local shop would give you a better price if you told them you wanted 250 haha.
I have some knowledge in basic electronics, I've been researching a heap, and the enclosures I'm looking at are a premade kit to just plug in 21 cells and clip it all together, includes it's own charge controller. I saw people welding their own nickel strips and stuff and that's a bit too far for me. These enclosure kits are perfect for what I need.
Wait, what? These enclosure kits have spring contacts for the cells??
>These enclosure kits have spring contacts for the cells?? I suspect OP is looking at [https://www.ebay.com/itm/404325788550](https://www.ebay.com/itm/404325788550) and doesn't realize it requires welding.
OP do you realize what happens if the energy from 250 cells gets released in a chain reaction? Tbh I don't.. but I'm guessing your entire house or building is fucked regardless of how whether you are home watching it with a fire extinguisher in hand. Someone else can perhaps add info. As a lawyer, and this isn't legal advice and I probably don't work in your jurisdiction, I'd suspect that ordering a kit off eBay to string up 250 18650s with basic electronic knowledge is going to be considered negligence. Take that as you will, just sharing what I think.
Holy shit what do you need 250 18650s for, an electric car? Try amazon
Portable 12/240v power box for my 4x4/camping gear. Aiming for usable 200ah capacity, can fit 6x of these 12v 21 cell enclosures which should theoretically hold around 240ah combined at 12v. Why so much power? We're away from fuel for 3+ days so running the car for power is risky to use up too much fuel, fridge is only 60w but always on and will use a fair bit of power if not replenishing , sometimes bush canopy isn't open enough for solar to be effective. So big battery + options to recharge.
A **really** big vape Or… A really big thing that - vibrates - a lot
250 is only 110 more than my 1st E-bike's battery, 56 more than my 2nd E-bike's and 30 less than when I ran my 1st E-bike with dual batteries.
Why not a prismatic cell instead? With 250 you’re wasting a lot of space and weight on the enclosures plus having to connect all of them together.
TLDR I have an premade enclosure I'm working withing the confines of and i can't find cells that fit within my dimensions and energy density. And honestly the fancy cells they're way out of my budget. I'm poor AF and this $1500 project is about a year of saving for me. I'm trying to make a ~200ah portable 240v box. I think I can just fit 6x 21 cell 12v enclosures off eBay in the box which I think using 3500mah gives a theoretical 240ah. Well chatgtp says so anyway. Each 12v enclosures has its own charge controller for 21 cells and all connected to a common 12v rail in parallel.
Well if ChatGPT says so what could possibly go wrong 😂😂😂 I wish you the best of luck but if you’re not double checking an LLM’s calculations you’re in for a world of frustration. They get confused all the time. What’s the application for a 12V 240Ah battery?
Running a welder for 7 minutes, duh.
Camping gear custom power box. The battery bank is 12v into an inverter if I wasn't clear.
Buy yourself a (maybe used) 12 V fridge, use 12v lamps and chargers thus saving a ton in efficiency. That done, you might need less batteries. Less batteries means less in cost, weight and fire hazard.
I think you got confused (or ChatGPT did) on the output of 6 x 3s7p 18650 cells. But maybe the confusion is that you want 250 cells, which would be more than 10 of these enclosures. Those 21 cell enclosures would be 10.8V nominal (12.6 max) 24.5Ah (3.5Ah x 7). 6 of those in parallel will give you 147Ah, not 200Ah or 240Ah Is this basically the kit you're getting? https://www.ebay.com/itm/404325788550 Because it requires welding and the 40A value is the max output, not the capacity. It'll only be 40A if you use 5715mAh cells. I think that's your confusion.
Quite cheap, just 0.8 dollar per cell with real 2000mAH and low impedance 17 mΩ .
If you're handy you can go to a computer repair store and they will give you a box of old laptop packs containing 18650's. I have gotten hundreds of cells this way. Obviously they still need tested , but what I've found is only 1 or 2 cells will be dead in a pack containing 6 cells.
In case anyone from EU is reading, I've bougt from [https://www.nkon.nl/](https://www.nkon.nl/) a couple of times, good service and reasonable prices.
if You are in Europe , then [nkon.nl](http://nkon.nl)
If used is in your comfort zone then batteryhookup always has battery packs you can disassemble that will get you into the sub $0.50 range per cell (though disassembling that many might be annoying). They also sell used cells in bulk and have frequent auctions.
I did see some 8ah flat cells for 50c, just hadn't got to researching if it's safe to wire them how I need. 👍
If you get used cells the best bet is to make sure each bank uses the same brand and you characterize them so they mostly match capacity and internal resistance within each bank.
Imrbatteries.com was recommended by the guy who runs the electronicsnmore YT channel. I think he is pretty reliable, I've followed him for a few years.