Oh, delightful. People soldering right onto lithium cells; always such a tremendous idea, both for instant excitement and longevity.
Also, my experience with old crusty laptops is that their batteries are completely shot. "Hooray, I have some 18650s with 400 mAh capacity! Winner!"
You shouldn't expect anything technical, it's Vice after all. Home energy storage is only useful in limited circumstances:
1. Large rooftop PV without grid-tie, or with grid-tie where the feed-in tariff is too low
2. Where the utility provides time-variant energy pricing.
"Hooray, I have some 18650s with 400 mAh capacity! Winner!"
You can easily find refurbished 18650s for less than $1 each that haven't been abused. There are threads about them here.
Also, my experience with old crusty laptops is that their batteries are completely shot. "Hooray, I have some 18650s with 400 mAh capacity! Winner!"
I know of one large engineering firm that buys about 3000 laptops from Dell every 3 years. Most of those spend 3 years sitting on a desk in an office plugged in, so the batteries would be in pretty good nick (relatively). They recycle all 3000 units on replacement. Someone gets a good deal there!
Hmm. I have maybe 1000 used 18650s, mostly still in the packs.
Kinda assuming you have 10 fingers, let us know how many you have after opening 1,000 packs. Two was enough for me (Dell laptop packs).
You shouldn't expect anything technical, it's Vice after all. Home energy storage is only useful in limited circumstances:
1. Large rooftop PV without grid-tie, or with grid-tie where the feed-in tariff is too low
2. Where the utility provides time-variant energy pricing.
Or when the grid in your area is not very reliable. Even if it is, the peace of mind is worth it for some. Smaller "powerwalls" (like the one I'm building) also come in handy for camping and other outdoor activities.
Oh, delightful. People soldering right onto lithium cells; always such a tremendous idea, both for instant excitement and longevity.
Rinoa Super-Genius has done that a lot with great success. (Of course, she's the kind who takes apart defective 18650s to study them...) The key is to use a very good soldering gun, add plenty of flux to the terminals, and work quickly. And if disassembling a pack to get the cells, try to leave some tab still connected to the cells to remove the need to solder directly to them.
Kinda assuming you have 10 fingers, let us know how many you have after opening 1,000 packs. Two was enough for me (Dell laptop packs).
I said 1000 18650s, not 1000 packs. Comprised of about 190 laptop packs, and a box of very good salvaged never-used cells.
Opening the packs is easy, if you are happy to play gorilla. I am. Trick is to use tools, not your fingers. To do a LOT of identical packs, probably jigs and power tools.
The packs are designed to discourage amateur attempts to open them. So don't be amateurish.
Btw, I've never had problems soldering to 18650 cells either. Surface preparation, then hot and fast. The inner roll structure has non-functional edges, and those are in contact with the cell base end, not the active stuff. Not very thermally conductive.
Also, I think it's best done with the cell mostly discharged, as a precaution.
Why am I getting an Amazon pop-up ad when I view this thread. Never had a pop-up from the blog before?
edit: solved, my little one was playing with my phone in the car the other day and she installed a video game that included a bit of ad-ware
Why am I getting an Amazon pop-up ad when I view this thread. Never had a pop-up from the blog before?
I don't. What browser and OS are you using?
I'm on my PC now and don't have the issue. iPhone 7 +, running iOS 11.2.5, I am installing the update to 11.2.6 now. I couldn't reply because the pop-up loaded and would not let me go back, clear. Anyway...I follow that up later.
I started my YT channel playing with 18650's and have built several small and very large recycled & new 18650 battery's. I have used direct soldering and spot welder. I prefer soldering even though some people despise it. I've run several experiments on new and old cells exploring exactly how much the extra heat from soldering effects the longevity of the cells and have not found any significant results.
edit: I would be happy to share the details of these experiments. I filmed the start of the last project and posted it, but YT flagged it (because I used the word explode?) so I just pulled the videos. They are tedious and boring but I believe it to be necessary for peace of mind. My first goal was to see how long it would take a soldering iron, set to 800 degrees F, to cause a cell to catch fire. Sadly, after 60 secs in direct contact with the cell, no fire. So I pulsed 300A into the same cell and that did the trick..lol. It popped like a firecracker. Then I went on to test 8 cells at a time, after applying heat to the cell for different periods of time, starting at 5 secs, up to 30 secs. Cells were cycled 100 times at 1A and capacity was recorded.
A few months ago there was a post to an eBay sale of 20 pack cells and I got one pack. Last night I started taking them apart and cut myself on a tab on the second battery and got two sets of sparks. So far two have tested over 2500 so now I can start throwing away my 400 laptop recycled ones. I opened three Dell sets and now all batteries have gone to battery heaven. In my opinion old laptop packs are not worth the effort. I am using my 18650s for a dog poop dryer.
When disassembling packs, cut/remove the negative tabs first, then spread the cells apart to get to the positive tabs without such easy chance for shorting positive tab to the negative case.
Contrary to the above, "dead" laptop packs are a good source for cells, not always, but often. I've salvaged cells with >2Ah from old packs that have been sitting in a shed for years, let alone "recently dead" ones. Of course I don't need to draw more than a few hundred mA from a cell in my usual applications, however even if I was building a powerwall the current demands per cell are low, so not much different really.
Soldering to cells is not ideal, if you have to you can, but it will impact the capacity negatively.
Commonly there is good cells in battery packs,
if you take apart the dead cells from battery pack
rest of the cells could be better than falsely claimed some ebay Chinese batteries.
Soldering to cells is not ideal, if you have to you can, but it will impact the capacity negatively.
Not ideal, why? WILL impact negatively, PROOF?.
I hear this all the time but no one seems to publish research. They assume the heat causes damage and think is dangerous..lions and tigers and bears..oh my. After soldering a couple handfuls, I took a dremel and then cut them open. I could not tell the difference between a new cell and one I soldered, and I tried very hard. I unrolled the entire cell and closely examined the edges from start to finish. And then I started my testing cycles described above. When done correctly, the heat created in similar to what a bLast from a 200-300A spot welder creates, just not as focused. I have the raw data AND I have the video footage to back it up. While I may not be on par with many of the topics in this forum, I am very much on the forefront with DIY 18650 projects. (hence the name, inverter powered by salvaged 18650's). But no need to argue, I have found the 'lab-coat-type's' despise soldering and that's great for the rest of us.
@TerraHertz, if you do not use them, you can sell them for a few bucks, so its a win,win.
edit:*If you are going to build a pack, I can send you a bunch of 18650 cell holders, trays, or whatever else you want/need for the build. I have a shop full of stuff and will be happy to be of service. Shipping is 'no worries', we can do the eBay global thing, its super cheap from here. (That's how I sent the Caddock resistors around the globe and it was just ~$8 a box.)
my video on how to get the good cells out
There's an Aussie bloke with a YouTube channel documenting his rapidly growing home-made power bank of recycled 18950s.
I don't know which bit of Oz he's in but it would be interesting for Dave to pop over to have a chat and make a video. (I realise that 'pop over' isn't really doable if he's in Perth and Dave is in Sydney)
There has been some studies involving tear downs showing that soldering 18650s slightly damages them internally. How badly it actually affects capacity is hard to tell. May be negligent especially for cells that are already not at their prime anyway. Soldering temp probably plays a big factor too. Want high temp so you can make it quick. But not too high.
My worry about soldering is when doing the positive. If solder spills too close to the edge it will short out. The entire body of the cell is the negative and wraps around fairly close to the positive at the top.
A laptop or DVD player is thrown away when a newer better one appears in stores. The battery is still good.
I used some 18650 cells from laptops in an electric model airplane and in a portable vacuum cleaner and the batteries work fine.
it was a pain to chop apart the batteries without damaging or igniting the battery cells.
Pete's channel is great. The other YT personality in the forefront is JehuGarcia, if you guys wanted to check them out. Jehu gets a large portion of his battery packs from eBay store, 'AlarmHookUps' out of PA. The store is run by a guy named Tom, who is always trying his best to get the cost as low as possible for DIY'ers. Full disclosure, I do some work here and there or Tom and have reviewed a couple of his battery banks in great deal.
A 30 kWHr power wall from used recycled li-ion batteries. Now who wouldn't want a neighbor with one of those?
A 30 kWHr power wall from used recycled li-ion batteries. Now who wouldn't want a neighbor with one of those?
Anyone who lives in an area where the power often goes out. "Hey, Pete, can you run a cord over for us again?" Haha.
Aren't you building a smaller pack? Hows that coming along? I read a few of your posts about the Arduino code and it sounds like your close to being ready to rock.
There's an Aussie bloke with a YouTube channel documenting his rapidly growing home-made power bank of recycled 18950s.
Hmm, the cute animated intro shows a mix of batteries (different colors), but his power wall uses a large number of all-identical cells. So I don't think those are recycled.
Another 'no details' bit of fluff.
Also, mounting the battery banks on flammable plywood, and no fire containment at all between banks. Really?
A 30 kWHr power wall from used recycled li-ion batteries. Now who wouldn't want a neighbor with one of those?
Anyone who lives in an area where the power often goes out. "Hey, Pete, can you run a cord over for us again?" Haha.
Aren't you building a smaller pack? Hows that coming along? I read a few of your posts about the Arduino code and it sounds like your close to being ready to rock.
My problem was that the solar charge controller I got was designed for 3S packs and that voltage is not a primary application for me (although I can use it). I ended up using the packs as-is and built an e-bike for them. I charge them with an MPPT charger, but the solar panel is usually connected to a PWM controller and 12V lead acid battery. After perusing the solar forums, I was told these (18650) are the wrong kind of batteries to use for solar energy storage - all things considered. However, I guess if they are salvaged none of that matters.
