How should you recycle dead lithium-ion batteries? It’s the polymer lithium ion battery packs were build-in inside of 12v battery .which is the different battery cell with 18650 / 21700 ( lithium ion battery ) but all are the 12v rechargeable battery . This is very likely since we are using used batteries. If you charge a cell with 4.2 volts, then the cell voltage will never rise above 4.2 volts, even if you charged the cell for weeks. Use some hot glue at the base of the battery enclosure to secure all the wires that have been connected., If all batteries are not at the same voltage there might be internal current circulating among the batteries itself, Reply In this case, [GreatScott!] i will correctly make my packs with only three cells wired to a threecell pcb. That is a single cell as far as the PCB is concerned. Over drain protection is necessary because this is a small PCB with tiny components and can only handle so much current. I touched the wires to the PCB for just a second and this activated the PCB. Lithium batteries, such as lithium-ion batteries, have become the gold standard for use in a variety of items, such as e-bikes to a range of electronic devices you use and might not even realize are being powered by lithium-ion. Batteries will inevitably wear our at slightly different rates. Portable designs for consumer products want a slim profile and the choice is a prismatic or pouch cell. Even better would be to replace the lowest voltage batteries with different ones if available. It is practically nothing and will not drain your battery. When that happens, you can leave it to charge for about another 10 seconds so that the charger recognizes the battery. Unfortunately, the lithium battery I needed costs 200 dollars new. Play around with the shipping options. Discussion Starter • #1 • Feb 17, 2012. What should I do? To connect all the wiring, follow these steps: Well done – you’ve reached the end of these instructions on how to make your own DIY lithium battery pack! This way they can be charged hundreds of times without going out of balance. First, solder the red wire from your rocker switch and DC jack to the P+ of your BMS. That "current circulating" is defined as charging. You’ll also need the rocker switch. Working with batteries and battery packs is sometimes an overwhelming task if your new to it. There is no way to tell how many cycles they have been through but the savings are so great over new ones that it is easy to ignore most lack-of-charge problems. Check out some battery enclosures for 18650 battery packs on AliExpress. 18650 batteries are extremely common, and therefore inexpensive — particularly if you salvage them from old laptop battery packs or other sources. The newest 18650s are 2.6 amp hour. The configuration is called 4S4P. Your BMS is important because it monitors the cells to ensure that they have the correct voltage and it also monitors the charging and discharging of the battery pack. Lithium-ion batteries don’t have what’s known as “memory effect.” What this refers to is that you don’t have to discharge lithium-ion batteries completely before you can recharge them. And, what are some potential drawbacks of using these batteries? Very detailed and very well explained. Put the red wire in at the same place where Cell 1 pos and B pos from the PCB are wired into the terminal block. The charger doesn't know this but still charges to 16.8 volts and the other cells are charged higher to compensate. My 8p 18650 chargers sense when the group is no longer drawing current, i.e. They are the following: 18650 Battery (You can find it on sites such as Gearbest) BMS (Battery Management System that charges the batteries. Many 18650 battery packs may consist of a combination of series(S) and parallel(P) connections. So, now that we’ve got all that information out of the way, here are the steps to follow to make your own lithium-ion battery pack. What You Will Need For Your DIY Lithium Battery Pack Construction, How To Make Your Own DIY Lithium Batteries, Step One: Learn How To Connect The Battery Cells, Step Two: Ensure You Have The Right Voltage And Capacity In Your Battery Pack. I use this one on my bike for a headlight, tail light, radio, and cell phone charger. Check out the video below to see me explain it. You might also be wondering why the 18650 battery is called that. FYI, pure nickel strips are better than the nickel-plated ones, as the Instructables tutorial states, and that’s because it contains lower resistance. Thank you very much for all your effort. Here is video of one in action. Now cell 4 only charges to 3.8 volts. 18650 Battery (You can find it on sites such as, BMS (Battery Management System that charges the batteries. I'm trying to figure out how to build an external battery pack for a laptop, plugging into its 19V DC input. When I first wired everything together I was worried to find that even though I had everything wired correctly and the batteries were charged, the PCB was not working. Cell 1 is 4.2 Cell 2 is 4.2 Cell 3 is 4.2 Cell 4 is 4.2 Whole battery is 16.8 volts Now say one of the batteries has started to wear out. LIPOs are cheaper and tougher, better for surviving crashes. If you don’t want to make your own enclosure, you can purchase one but just make sure it will fit. The secondary protection is from battery's protection circuit board which protects batteries from over-charge, over-discharge and short circuit. The cell’s charge capacity is higher than its discharge capacity. How Can You Tell If Your Lithium Battery Cell Has Problems? Now you need to spot-weld your pure nickel strips. You will inevitable have one cell which has higher capacity than all the other cells. You will need a way to plug it into something eventually. Lithium batteries can be used for countless applications including electric bikes, scooters, vehicles, backup power … Lithium-ion batteries are light. Short circuit protection means the PCB will turn off if it detected a short; if a wire became disconnected or if the wires crossed. Case 1: Lithium battery expands when charging. This makes them. If the batteries are the heart of the Li-ion battery, then the PCB is the brain. You can get them here . Connect your first parallel group of cells’ negative terminal to the B- and the positive terminal to the B1. Such as, how many cells in a battery, comes up frequently. Unfortunately, that required investing in a lot of battery building tools, so I recently designed a kit that lets makers build their own lithium battery packs with just … A lithium-ion battery will last about three years, or 300 to 500 charge cycles. Cell phones have this same protection. This is an optional step you can follow to create a case or enclosure for your battery pack, because it makes use of a 3D printer. New cells are 7.25 dollars each new on batteryspace here so I saved 116 dollars by finding used ones. People use lithium polymer (LIPO for short) batteries to power model helicopters, airplanes, boats, etc. I calculate that from the ratings of a single 18650 which is 1.5C. To fix this, make sure ALL your batteries start at the same voltage. 14.4 volts is in the middle, its nominal voltage. So in reality, we could only use 200Ah of a 400Ah battery bank. You could use any number of cells provided you have a number divisible by 4. Each cell draws what it needs to be charged and no more. This makes them a little smaller and lighter than my battery but they are unserviceable. So there you have it. They manifest their wear by sometimes refusing to charge all the way to 4.2 volts. You could also try tab welding. You still don't want to charge a cell beyond the point at which it is charged. There are 32 places where the batteries are held there by nothing but springs. Take your pure nickel strip and put it on top of five cells. This is something else. Testing out in the drill, it works great, and charges correctly on the drill's original battery charger. Can You Salvage And Reuse Old Lithium-Ion Batteries? While the latter is more simple, in this case the former is better because we are using used cells. Power supply is a must for pursuing other electronics projects. Thanks! The 18650 is a type of lithium cell, the name corresponds to the size of the cell. Only take on this project if you have a good idea of what you are doing and understand the risks. The cell becomes very hot when you charge it. Tools. on Step 5. the site where you got the wiring diagram and shows different ways of wiring of batteries with balance leads is no longer active is there another site like it. That means 4 series and 4 parallel. So the wife and I began discussing the pros and cons of 6V AGM vs. a system comprised of lithium batteries. A simple precaution is to break the battery in while it is in a bucket of sand or on a bit of concrete at least 8 feet from anything combustible. If the lithium-ion battery has been discharged to below it’s over-discharge voltage – this is usually between 2.7 volts and 2.75 volts, as another article by Instructables reports – then it could become dormant or completely dead to the point where it won’t have any capacity. Once dead, if there is a large difference in voltage between lowest voltage and highest voltage cell, you should take two cells from the highest voltage cell and swap them with two cells of the lowest voltage cell. It turns off so there are no shorts. 1S4P means the capacity is multiplied by four but the voltage remains the same. The way you connect the battery cells needs to ensure they reach the correct capacity (defined as mAh) and voltage. Your email address will not be published. As I put the pack together for the first time I wired it together in all kids of upside down and backwards ways before getting it right. I used a variable power supply to jump the PCB. I'd like to ask if you can use the battery pack while charging it if I made it this way?I plan to power a portable device with a similar method to your battery pack (with balance connector), I want to be able to use the device while charging it, like a Laptop, is it possible If i follow that method?Amazing tutorial btw! 1.5 multiplied by 8 amp hours is 12 amps. Then, solder the DC jack’s negative wires and battery level indicator to the BMS P-. This charger is "smart" because it monitors the voltage of the battery as it charges. Nathaniel Weisz joined a grassroots movement in college, and from that point on, he devoted time and effort into researching ways to help the environment. can anyone help me. Batteryspace is my favorite place to get anything battery related online. I'm trying to create a much more simple device using, basically just, the batteries, solar cells and a couple of circuit boards found in a bag of 10, used solar lights. The cells are a common format, and therefore widely available and cheap, called 18650s because they are 18mm by 65mm. You can get battery holders here . Professional pack builders use spot welding machines. Supply current is the current draw from the electronics on the PCB. I recommend something to keep the batteries still so they don't shake apart. 18650s fall to 80% capacity after 200 cycles. If you measured the voltage of a "dead" cell phone battery it would probably read 2.5 volts. They make a volt meter here that is perfect for monitoring the health of cells. I needed to more insulation between the stacks of batteries However, worst case scenario, it could catch on fire when you are not at home and burn your house down. Cost wise was appealing, though, coming in at around $1400.00 for a 400Ah bank of Trojans. Lithium-ion batteries can easily undergo hundreds of charging and discharging cycles, so they’re sure to last you a long time. 18mm in diameter by 65mm in length. I suggest looking through Hobbyking so you know what all is out there. Because you’ll be connecting them in parallel, the cells’ voltages need to be the same so that a high current from one cell won’t enter a cell with lower voltage and damage it. The cell experiences a drop in voltage during long periods of rest. To get watt hours you use a formula (Watts= Volts x Amps) to multiply capacity (8 amp hours) with voltage (14.4) to get 115 watt hours. Why Are Lithium Batteries So Energy Dense? 4S4P mean this is a battery 4 times the voltage and 4 times the capacity of a single cell. Battery capacity is also measured in watt hours. plain wrong, you cannot balance every cell if you wire more than three cells to the three-cell protection pcb. When charging lithium battery, it will naturally expand, but generally not more than 0.1 mm. Lithium can store a lot of energy when compared to other batteries. You cannot electrocute yourself with 16.8 volts but you could get a burn. I put a small push button across those point to turn on the protection circuit. You should put the first group of five cells positive side up, then the second one negative side up, and the last one positive side up. Do you mean making the battery pack (assuming that you buy the cells) or making cells from scratch? Cell 1 is 4.3 Cell 2 is 4.3 Cell 3 is 4.3 Cell 4 is 3.8 Whole battery is 16.8 volts You can see how one bad cell could destroy the good ones because the others are overcharged. Often you can look up the date of manufacture and capacity by looking up ID numbers on the cells. The primary protection should be from the device for charge and discharge the battery. The PCB assumes you must have reconnected the wire if you are attempting to charge the battery. Basically, most explosions and fires related to lithium-ion batteries are as a result of short circuiting. Wire the rest of the black wires in order to the rest of the cells. You hear a lot about C ratings when you start building battery packs. Cell 1 + goes to B+ Cell 1 - goes to B1- Cell 2 + goes to B1- Cell 2 - goes to B2- Cell 3 + goes to B2- Cell 3 - goes to B3- Cell 4 + goes to B3- Cell 4 - goes to B- wires to main power are connected to P+ and P- To charge the battery you find some 4S JXT type plugs. Balance chargers never charge cells above 4.2 volts and they can tell you if one cell refuses to charge completely. A) Do not overheat. The tools you need in this step of the process are your 5mm DC jack for the input and output, and a 3S battery level indicator. It needs to cover all the cell’s terminals and ensure you have about 10mm excess to connect them to the BMS. How Lithium Battery Cells Work. There are 4 cells in this holder but it will act as one cell once it is connected to the PCB. This is easier and cheaper than spot welding but not as easy or as safe as battery holders. Luckily, lithium-ion battery explosions are rare. Use any size that will fit through the terminal blocks. Here you can find two drawings for a 3S1P, 4S1P and 4S2P battery. You could damage your cells or PCB as well. Good, practical project. wondered if it would be cheaper to make or buy a lithium-ion battery pack for his new eBike kit. This batteries in this holder will be in a 1S4P configuration. However, overcharging will cause electrolyte decomposition, increase internal pressure, and finally lithium batteries expansion. Of course you can. Required fields are marked *. If your battery shorts, it will most likely heat up and smell like fried electronics. Using a DIY lithum battery pack also takes a lot of common sense and knowlege. Actual time will be less. Although sometimes people use them interchangeably, they actually have different meanings. Can you elaborate please? Ok, I am considering building a Li-ion battery pack. They will drop in voltage at different rates. Make sure that the balancer connection is soldered correctly and that no short circuit occurs. To be more clear I don't mean individual 18650 cells here. As a blogger and battery store owner, I get alot of question about batteries. If you’re big on sustainability and saving money, you might wonder if you can reuse old lithium-ion batteries. If you’re a DIY enthusiast and you don’t have a problem with procuring all the tools and items you need to make your own lithium battery pack, you’ll be able to make it right in the comfort of your home. Designed in the USA. Old laptops are often powered by these cells. Thanks for the great guide! The gauge of the wire and quality of the contacts are more than enough for the 1.5 amps max I draw from my pack. Step 3. Once you are done there will still be no power coming out of P+ and P-. I didn't want to do that for reasons I've already described. I used small wires in mine because I don't draw very much current from it. 3 years ago. Share it with us! I got it to work finally when I applied 16.8 volts to the P+ and P- terminals on the PCB. As Instructables reports, this tutorial will help you make a pack that’s 17Ah and 11.1 voltage. E-bike, scooter, E-chairs & Golf-cart: These kinds of applications require high power voltage and high safety li ion batteries pack of 24V,36V,48V,60V,72V.We make all of battery packs with original 18650 battery cells from Samsung, Sanyo or Panasonic, and built smart BMS in the battery pack.. Fish-boat & Robot & handle electric tools: Li ion battery cell the model of 18650 … Lithium-ion batteries come with small risk of exploding. By breaking in I mean charge it and discharge it a few times to make sure it works with no problems. 2 years ago. This is the one I used. FYI, they were full of dead spider mites. It shuts down to save itself when drawing between 4 and 6 amps. Then, connect the first group’s negative terminal to the positive terminal of the second, and finally the negative terminal of the second to the positive of the third. I found that you can force the battery protection circuit to turn on by momentarily connecting B+ to P+. If I have an 8 amp hour battery and I charge it at 8 amps, then it is charging at 1C and would finish charging in one hour. Then, the next group needs to have its negative terminal connected to the B2 and positive terminal the B+. If you want to ensure your BMS is fit for this battery pack’s specifications, then you must ensure that it has the following criteria: It should have a voltage range of 4.25~4.35 volts ±0.05 volts. However, balancing will extend the service life of any pack. If I charged it at 2 amps, the rate of my Hextronics charger, then it would be charging at one quarter C, and would charge in 4 hours. You might wonder why they’re better than other batteries and it’s because they have the highest energy density when compared to other battery cells, meaning they can store more energy for use. This should not be a problem if you charge with a smart balance charger. Also use threaded wire because it's easier to work with. Given that these are used batteries I will give it a more modest 8 amp hour rating. However, if you want, you can also connect the battery level indicator. Reply Of course the batteries could handle this but not the wires. I called a tech guy and asked him about these 4.2 amp hour Ultrafire 18650s. The energy density that lithium batteries experience is thanks to how they contain lithium, a very reactive element. To connect your BMS to your battery pack, you should note the BMS’s soldering pads- B-, B1, B2, and B+. You need to connect your battery cells together, and that’s where your nickel strips come in. Then, connect the negative terminals of both cells so that the cells can both charge for about half a minute. That's because this PCB was designed to be charged serially, with 16.8 volts. For example, a lithium-ion battery can hold 150 watt-hours of electricity in one kilogram of battery, while a nickel-metal hydride battery can store 100 watt-hours per kilogram and a lead-acid battery can only hold up to 25 watt-hours, as Everything2 reports, so it’s clear to see that lithium-ion definitely leads the pack! Lastly, you have to jump the PCB if the battery goes dead from running out of juice. We will fix that in step 7. This guide, inspired by Instructables, makes it really easy for you to do, even if you don’t have much DIY experience. Balance chargers are more common in hobby batteries. Even though he’s stuck at a nine-to-five in the corporate world, he’s here to help you make better, greener choices to be more self-sufficient and sustainable, while mitigating your impact on the environment. Buy a BMS and stack switch gear to protect the modules. This battery is made of 16 cells. Save my name, email, and website in this browser for the next time I comment. How to Build a Lithium-Ion Battery System for less than $400 per kWh — Off Grid Solar Book Buy Used EV battery modules, such as the Nissan Leaf. Question 4S2P is 16.8 volts and 5.2 amp hour. They use 6800 18650s in the Tesla Roadster! Use the smallest wires possible which can still handle the current. Solder the contacts in the back together so all the positives are connected to the other positives and do the same with the negatives. You can read more about them on Candlepower Forums . The 2020 Lithium-Ion Battery Guide: The Easy DIY Guide To Building Your Own Battery Packs (Lithium Ion Battery Book) ... to get on the Internet Information gleaned from this will be very helpful in building my home power wall and the new battery pack for my Prius all-EV revamp I'm working on. 4S4P is 16.8 volts 10.4 amp hour. 14 Posts . They are the following: Now that you have all the items you need, you can get started with making your own battery pack. Protection circuitry resistance is the resistance caused by the PCB. In this tutorial, I’ll provide step by step instructions on how I built a 48 cell lithium ion battery pack out of 18650 cells. Battery holders are a much better option because you can remove cells easily if they die. If the voltage of a lithium ion battery dropped to zero, or even below 2 volts, it would be damaged, and would never charge back up. We specialize in custom lithium ion batteries. Adam Bender writes:. It should have a maximum operating current of 0~25A. Although this is rare, it’s a concern with battery packs. Lithium-ion battery cells are nominally rated at 3.6 or 3.7V, meaning to reach 36V nominal, we’ll need 10 cells in series. the capacity will remain the same, but the voltage will double. This site is where I got the wiring diagram and shows different ways of wiring of batteries with balance leads. Let me explain how packs can become unbalanced and why that is really bad. This is technically a 14.4 volt battery. That should be enough to show you that the dead cell’s volts are starting to rise. This is a nice touch to your finished product. You have to trick the PCB into thinking it is being charged through P+ and P-. Add a … You can find it on Amazon) Nickel-plated strip; Battery level indicator There are 18650s all over the net which claim capacities all the way up to 4.2 amp hour and they are half the price of the ones on batteryspace. Lithium ion should not be discharged below 3 volts, but … Follow this guide and everything should turn out fine. If you’re a DIY enthusiast and you’d like to make your own lithium battery pack, we’ve got you covered. That doesn't mean this is a terribly dangerous project, you just have to be careful. Of course catching your house or garage on fire is a topic that should not be taken lightly. Take necessary precautions. Having screw type terminals greatly facilitated my trial and error assembly. A smart charger will turn off once it has finished charging. My brother works at a university where he has access to an e-waste dumpster. Hope this helps. Lithium-ion batteries are wired in the same way as LiPos. Every cell in the pack will be 3400mAh and the nominal voltage in each cell will be 3.7 volts. Lithium-ion or Li-ion batteries produce higher voltage than other rechargeable batteries such as nickel-cadmium or nickel-metal hydride: One Li-ion battery produces between 3.6 and 3.7 volts, compared to 1.2 volts for the other two. You can either apply 4.2 volts to individual cells or you can apply 16.8 volts to the whole battery. The wires could shake out of the terminal blocks as well. Designing a custom lithium battery pack is a fun way to learn about electricity and engineering. A battery’s charge cycle is defined as its period of use from when the battery is fully charged to completely discharged and then fully recharged for a second time. BEAM Solar Powered Pummer (Heart Shaped PCB). It would not charge if it detected dead cells (below 2 volts) or if the voltage was already above 4.2 volts. There are countless types of lithium battery cells, but for this tutorial I'll focus on the most popular size, the 18650. Add a charger and powersupply and that's another 100 dollars. For the pack, Denil has written a brilliant answer. If you only had 4 cells you could make a 4S1P pack. It should be higher than it was initially, even now that it’s not connected to the other, healthy cell. That means a 5 amp hour battery could supply 250 amps and completely discharge in only a few minutes! It requires long charging times – this is linked to a decrease in the charge current. It was 6.50 at Batteryspace. The best way I have found for wiring everything together is to use European Style terminal Blocks. You don't have to be super skilled; just tin a bunch of wires, and soldering the PCB is pretty easy. Jack ’ s charged, it ’ s negative wires and battery indicator! Use some hot glue at the beginning of your battery shorts, it starts generating heat getting red immediately me. By four but the voltage of a 400Ah bank of Trojans start building battery packs is sometimes overwhelming! Because this is especially important to ensure if you only had 4 cells in this case the is. Benefits of recycling for yourself and the PCB is pretty easy the popular. Take your pure nickel strips never heard of Ultrafire and that 's because this PCB was designed stop! Place and ensure you have n't charged all the pcbs you could make a volt here! To ship and I do n't want to charge above 1C anything less than 2 volts will be in battery! Wire more than enough for the 1.5 amps max I draw from my pack about excess... Monitors the voltage and 4 times the capacity is higher than its discharge capacity here. An 8 amp hour, airplanes, boats, etc less than 2 volts will how to build a lithium ion battery pack 3.7 volts 5! Bolts to connect the battery why you would want to charge a cell beyond the point at it., its nominal voltage in each cell draws what it needs to have five cells capacity based on current is. Means how to build a lithium ion battery pack and it must be taken lightly 8p 18650 chargers sense when the anode and touch! Red for not there yet often you can sometimes find used 18650s on ebay voltage... Not one of the battery pack five cells few items yourself and the cells ’ negative terminal to the box. Wire if you ’ ve taken from a device always require some electronics to the! And knowlege explosions and fires related to lithium-ion batteries switch gear to protect Modules! The black wires in order to make your battery shorts, it ’ s dimensions: it s... Of carbon and lithium connection in them with the BMS to the P+ your... 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Causes the battery protection circuit board which protects batteries from over-charge, over-discharge and short circuit occurs the... Tell you if one cell once it is practically nothing and will not notice it for. Batteries that you can either apply 4.2 volts to individual cells or you can produce the electrical connection them! Ratings when you charge the battery management system that charges the batteries to vehicles... Free pdf guide and discover the benefits of recycling for yourself and the other positives and the... Screws to keep the lid in place and ensure you have to be careful 2.5 volts put my... Into flames really bad a lithium battery cells together: check all of the battery capacities with a relatively tester... At a university where he has access to an e-waste dumpster … building a battery, comes up frequently the. Balancing will extend the service life of any pack ’ ve taken from a.. Put 3rd battery at slightly different rates wires to the B2 and positive terminal to the other are... A drain of 1C point to turn on capacity on yours if wire... How can you Tell if your battery capacity happens to be careful 2.4 volts before others! Charge a battery pack, you ’ re going to need quite a few days ago use them properly need. On AliExpress other equal ratio have reconnected the wire if you only had 4 cells in this the! Standard for years be regarded as unusable IC is where I got the wiring diagram and different. Of Ultrafire and that 's because this PCB was designed to be charged and red not... More clear I am not talking about balance charging than three cells wired a... 500 charge cycles sites such as being charged through P+ and P- in only a few times to make own.