Re: [time-nuts] Li-ion Battreries
Hi Mark: I agree. The Vietnam era PRC-25 radio had a solid metal battery box that was water tight and used a BA-4386 battery with Magnesium chemistry. http://www.prc68.com/I/PRC25.shtml#DCP The problem was that as a normal part of its operation the battery releases hydrogen gas. I know someone who has a scar on his head because when he opened the battery box the pressure shot it into his face. No chemical explosion, just gas pressure. The more modern radios that use the BA-5590 (BA is military speak for primary) Li-SO4 battery where the sulfur is compressed to make it a liquid have been known to explode if you try to charge them. This has resulted in a requirement for all battery boxes/spaces to allow for one cell to "vent" and not cause a problem. This is even more important with the current BB-2590 (secondary/rechargeable) battery made up of a couple dozen 18650 Li cells. http://www.prc68.com/I/BA5590.shtml#BB-2590Inside PS This "5590" family of batteries are all form-fit-function interchangeable and are made up of two "12 Volt" batteries in one 5.0 x 4.4 x 2.45" box. It's the standard battery in the military for non vehicle applications that need vehicle compatibility (ie either 12 or 24 volts). The radio or host device can wire its plug so the battery appears as either a 12 or 24 volt battery. While the long in the tooth BA-5590 can only supply a couple of amps (internal fuse) the newer BB-2590 can supply maybe 35 Amps for a short time, I think to start a motor. Rather that buying raw 18650 cells and connecting them getting a BB-2590 may be a better option. There are numerous military chargers that can charge them as well as hobby grade chargers that work with Li cells. There are some very low cost battery capacity testers on eBay: http://www.prc68.com/I/BatTst.shtml#Resistor - good for 18650 cell testing http://www.prc68.com/I/BatTst.shtml#EL - good for BB-2590 testing -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message They can be if you store them in something like an ammo box. If they "go off" in the sealed box the pressure builds, the reaction rate increases exponentially, and voila... shrapnel time. There's a video out there showing the results. Most people recommend storing them in nomex/kevlar "cell bags". I keep mine, bagged, in an unused/unplugged oven! If one goes off, hopefully the flames won't spread to the rest of the property and the hinged oven door allows pressure to escape. Hobby RC packs are one of the most dangerous type of rechargeable lithium cells out there... even from "reputable" sources and brands. A local hobby shop twice had brand new name brand packs sitting on the shelf go off. A friend of mine had the same thing happen carrying a just purchased pack home in his car. They aren't bombs, guys. Use sensible precautions and get on with it ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
No way will an ammo box explode and send shrapnel flying. Even if filled with machine gun bullets and tossed in a fire. The rubber gasket fails and the pressure escapes. A slow burning object like a battery will never cause steel to fragment. If someone made a video it was faked The purpose of the box is that first it offers mechanical protection in storage and transport and second it is a heat sink. If a few hundred watts of energy is put into a small part of the box, the heat conducts to a larger area and you have a lower temperature. The box is designed to store ammo in a combat area, the box will not explode if something inside of it catches fire. The gasket would fail first or it not the wire bail holding the lid would fail under minimal pressure. The lid opens LONG before the steel can bursts If I wanted to make a dramatic video, I'd fill the entire box with gun powder. The lid would fly open and burning powder would to ejected into the air and it would LOOK like an explosion On Sun, Jan 22, 2017 at 6:25 PM, Mark Sims wrote: > They can be if you store them in something like an ammo box. If they "go > off" in the sealed box the pressure builds, the reaction rate increases > exponentially, and voila... shrapnel time. There's a video out there > showing the results. > > Most people recommend storing them in nomex/kevlar "cell bags". I keep > mine, bagged, in an unused/unplugged oven! If one goes off, hopefully > the flames won't spread to the rest of the property and the hinged oven > door allows pressure to escape. > > Hobby RC packs are one of the most dangerous type of rechargeable lithium > cells out there... even from "reputable" sources and brands. A local > hobby shop twice had brand new name brand packs sitting on the shelf go > off. A friend of mine had the same thing happen carrying a just purchased > pack home in his car. > > > > > They aren't bombs, guys. Use sensible precautions and get on with it > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
Whatever makes you feel safe, Mark. The internet has a plenitude of horror stories, some of which would make you think that the only prudent course was to store them in an underground bunker. Our study used several hundred batteries, all stored in surplus cal .50 ammunition cases in manufacturers' packaging. We had no explosions, no fires, no spontaneous combustions, no drama at all. But do what makes you feel safe, by all means. On Sunday, January 22, 2017, Mark Sims wrote: > They can be if you store them in something like an ammo box. If they "go > off" in the sealed box the pressure builds, the reaction rate increases > exponentially, and voila... shrapnel time. There's a video out there > showing the results. > > Most people recommend storing them in nomex/kevlar "cell bags". I keep > mine, bagged, in an unused/unplugged oven! If one goes off, hopefully > the flames won't spread to the rest of the property and the hinged oven > door allows pressure to escape. > > Hobby RC packs are one of the most dangerous type of rechargeable lithium > cells out there... even from "reputable" sources and brands. A local > hobby shop twice had brand new name brand packs sitting on the shelf go > off. A friend of mine had the same thing happen carrying a just purchased > pack home in his car. > > > > > They aren't bombs, guys. Use sensible precautions and get on with it > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- If you gaze long into an abyss, your coffee will get cold. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
Those hobby packs are typically LiPO, chosen for the energy density, and they often (usually?) run them with minimal protection circuits to reduce weight. Not recommended practice for building devices. BMS When I built a 12 cell series 10Ah pack, I went with LiFePO4 and a custom-configured Battery Management System (BMS). The BMS doesn't balance the charge after charging (which consumes time & energy), but runs a separate lead to each junction between cells so it can monitor each cell to vary each cell's charging to bring each to cell Vmax without going over. Those leads also allow each cell to be monitored against under voltage (cell Vmin). The cheap alternate is to rely upon monitoring pack Vmax and pack Vmin protection, but this is a recipe for killing a cell, as a cell may go over or under voltage while the pack voltage appears within the safe range. The LiFePO4 cell I chose is interesting for its self-containment. Headway 38120, which was recommended as the cell is built encased within a containment shell with a threaded terminal on each end. The negative end's terminal is entirely sealed. The positive end's terminal is also sealed, but there are air holes spaced around the cap-to-container join and the true seal is an inner cap under that terminal cap (visible through those holes). When the cell fails, rather than pressure causing a leak, the inner sealing cap can expand into the space under the terminal cap thereby relieving a critical level of pressure. Or so it's claimed; I've never had an incident to test that. Michael On 22/01/2017 9:25 PM, Mark Sims wrote: Hobby RC packs are one of the most dangerous type of rechargeable lithium cells out there... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Li-ion Battreries
They can be if you store them in something like an ammo box. If they "go off" in the sealed box the pressure builds, the reaction rate increases exponentially, and voila... shrapnel time. There's a video out there showing the results. Most people recommend storing them in nomex/kevlar "cell bags". I keep mine, bagged, in an unused/unplugged oven! If one goes off, hopefully the flames won't spread to the rest of the property and the hinged oven door allows pressure to escape. Hobby RC packs are one of the most dangerous type of rechargeable lithium cells out there... even from "reputable" sources and brands. A local hobby shop twice had brand new name brand packs sitting on the shelf go off. A friend of mine had the same thing happen carrying a just purchased pack home in his car. > They aren't bombs, guys. Use sensible precautions and get on with it ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
On Sun, Jan 22, 2017 at 9:36 AM, Mark Sims wrote: > I have a LOT of experience in testing and using 18650 cells. It is a > horrible place for the un-initiated to be. The market is so saturated with > dangerous fakes and inferior, over-speced cells that finding a genuine cell > is a vanishingly small probability. Hopefully the seller mentioned before > pans out and sticks around. I agree, many fakes. But you CAN buy through reputable distributes like Amazon.com for maybe $16 per cell. When I buy a battery packs the cells are already shrink wrapped and who knows what is really inside, so I test the pack. I charge it up and then discharge it through a dummy load and track the power over time (actually my programable charger can do this for me) then I recharge it ti to "stage age voltage" and check that the self-discharge rate is reasonable. I've not had a problem with hobby type drone batteries and if I did I'd be covered by even a 30 day warranty or failing that by PayPall's chargeback policy. I'd 100% recommend that anyone who buys a lithium battery place it inside a fire proof enclosure then run it through a few charge/discharge cycles and very the seller's specifications. If you are not set up to do this kind of acceptance testing don't buy lithium. I can say first hand that once the lion battery fails, boiling electrolyte and white smoke will continue to come out of the battery no batter what you do, just take it outdoors and set it on the concrete and let it finish, dropping the assembly in a bucket of water will not help, they will generate a few hundred watts of heat until they run out of energy. One started it is a positive feedback loop. But not dangerous if you thought ahead to place the thing inside some metal container. Just carry the smoking mess outdoors and leave it there for a while.(I tried salvaging lithium cells for Milwaukee power tools with only about 50% success rate) -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Li-ion Battreries
In the days prior to my recent retirement, when I was directing research at a large VA Medical Center, one of our projects used inordinate quantities of 18650 Li-ion batteries. We found in short order that buying from Amazon or eBay was penny wise and pound foolish. Rather than flogging the internet for deals, trying to save a few bucks, just buy Panasonic, Duracell, Sanyo, Samsung Sony or LG directly from an authorized dealer. As Chris pointed out, ammo boxes work are excellent for storage. We found the manufacturer''s packaging perfectly adequate. They aren't bombs, guys. Use sensible precautions and get on with it. On Sunday, January 22, 2017, Chris Albertson > wrote: > I'm using Lithium batteries too. Button for everything. For stationary > lab bench use where AC mains is available and all I want is back up our the > lead/acid gel cells work fine. They are cheap, large and heavy and will > take abuse and don't normally catch fire. > > For the mobile devices that I like to build nothing beats Lithium > batteries. I've been using the kind sold for use on remote controlled > drone aircraft. They have incredible power density and low cost. Their > biggest down side (an advantage to me) is their lack of consumer > appropriate packaging. The cells are only shrink wrapped and are easy to > damage. I change them with a programable "balanced" charger that is > commonly used by hobbyists. > > I have found that YES you can start a fire from carelessly handing Lithium > batteries. You do have to understand how to use them and keep them > packaged such that they remain safe even if they fail or (more likely) you > make some mistake. I keep them in fire proof glass fiber/silicone > envelopes then inside a tightly close steel "ammo box". When in use > they are installed in the mobil device I built in a metal compartment (I > use those old fashion Japanese lunch boxes, they are like Tupperware but > made completely of metal) > > Get these batteries at any of the Hobby supply outlets (NOT eBay, lots of > fakes there.) > Here is just one example of the last set I bought > https://hobbyking.com/en_us/zippy-flightmax-4000mah-4s1p-20c.html > > > > On Sun, Jan 22, 2017 at 9:13 AM, Adrian Godwin > wrote: > > > Recovered cells aren't only sold through ebay parts adverts - they're > also > > used for production. I recently bought a few cell phone boosters which > > consist of an 18650, a charge circuit and a voltage booster to 5V. > > > > They were low cost and nicely made with an extruded aluminium case and > they > > worked very well in my application. But on taking one apart, it was > > apparent that they'd used a recovered cell. > > > > I've no complaints given the price, but be aware that the cell phone > packs > > may not be new either. > > > > > > On Sun, Jan 22, 2017 at 4:48 PM, Didier Juges > wrote: > > > > > Well worth mentioning that you have found a reputable vendor. I may > give > > > them a try. > > > > > > A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 > > > vendors picked at semi-random on eBay (4 from each) for evaluation and > I > > > tested each one of them with a data logger. > > > The best one had about half the advertised capacity, the others went > down > > > from there. Important to observe that none of the set I bought were > even > > > remotely matched, a crucial consideration if you are going to put them > in > > > series (a balancer will only ensure your pack is no better than the > worst > > > cell in the pack). > > > Many of the 18650 cells you find on eBay (and maybe other places) are > > > actually coming from old laptop battery packs that normally should have > > > been discarded/recycled. > > > > > > In my anticipated application, I only needed one cell (to be followed > by > > a > > > small boost converter), so the issue of balance and matched set was not > > > important, but simply I needed the capacity and none were remotely > > > satisfactory. I ended up using cell phone booster packs, since I needed > > 5V > > > anyway. > > > > > > > > > On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < > > > time-nuts@febo.com> wrote: > > > > > > > I use 4 cell balancing and protection circuits, cost a couple of $ > more > > > but > > > > well worth it, I use holders because of limited availability of > cells > > > > with straps, but rest assured they are held down (discarded PCB)'s, > > > > I on purpose did not get into technical details I was only trying to > > > share > > > > reliable sources, based on disappointing past experiences. > > > > Bert Kehren > > > > > > > > > > > > In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, > > > > att...@kinali.ch writes: > > > > > > > > Hoi Bert, > > > > > > > > On Sat, 21 Jan 2017 08:08:22 -0500 > > > > Bert Kehren via time-nuts wrote: > > > > > > > > > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain > > Rechargeable > > > > Battery > > > > > INR18650-35E_ > > > > > > >
Re: [time-nuts] Li-ion Battreries
The reason I made the post is after bad experiences I found a vendor with genuine product and willingness to send you data sheets and my tests confirm data within 3%. Can not ask for more. Can tell all the stories mentioned, been there done it, that is why I felt it will be useful for time nuts. The Samsung data sheet is 752K otherwise I would attach. Claim 3350mA and 100% at 0.2C that is what I tested and got 3327mA well with inn my test setup. Bert Kehren In a message dated 1/22/2017 12:45:41 P.M. Eastern Standard Time, hol...@hotmail.com writes: I have a LOT of experience in testing and using 18650 cells. It is a horrible place for the un-initiated to be. The market is so saturated with dangerous fakes and inferior, over-speced cells that finding a genuine cell is a vanishingly small probability. Hopefully the seller mentioned before pans out and sticks around. You can be pretty much assured that any no-name Chinese cell will be dangerous crap. Buy a 3000 mAh cell that is really 500 mAh and charge it at the 3000 mAh 1C rate and KERBLOOIE! If you want to buy decent cells from a reputable maker (Samsung, Sony, Panasonic, etc) you have to be certified that you know how to properly build with and use them... and also the minimum order quantity can be over 100,000 pieces. Shop around and you can find sellers of 18650 shrink wrap sleeves for all the major/reputable cells. I have yet to test a Chinese cell that comes even close to its advertised specs. Also probably 90+% of what is offered as genuine name brand cells are fakes. Your best bet for finding a decent cell is to get them from GENUINE laptop packs. That is easier said than done... counterfeit packs are the norm. Also, most newer laptops use packs with pouch cells. 18650's are on the way out for modern machines. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
I'm using Lithium batteries too. Button for everything. For stationary lab bench use where AC mains is available and all I want is back up our the lead/acid gel cells work fine. They are cheap, large and heavy and will take abuse and don't normally catch fire. For the mobile devices that I like to build nothing beats Lithium batteries. I've been using the kind sold for use on remote controlled drone aircraft. They have incredible power density and low cost. Their biggest down side (an advantage to me) is their lack of consumer appropriate packaging. The cells are only shrink wrapped and are easy to damage. I change them with a programable "balanced" charger that is commonly used by hobbyists. I have found that YES you can start a fire from carelessly handing Lithium batteries. You do have to understand how to use them and keep them packaged such that they remain safe even if they fail or (more likely) you make some mistake. I keep them in fire proof glass fiber/silicone envelopes then inside a tightly close steel "ammo box". When in use they are installed in the mobil device I built in a metal compartment (I use those old fashion Japanese lunch boxes, they are like Tupperware but made completely of metal) Get these batteries at any of the Hobby supply outlets (NOT eBay, lots of fakes there.) Here is just one example of the last set I bought https://hobbyking.com/en_us/zippy-flightmax-4000mah-4s1p-20c.html On Sun, Jan 22, 2017 at 9:13 AM, Adrian Godwin wrote: > Recovered cells aren't only sold through ebay parts adverts - they're also > used for production. I recently bought a few cell phone boosters which > consist of an 18650, a charge circuit and a voltage booster to 5V. > > They were low cost and nicely made with an extruded aluminium case and they > worked very well in my application. But on taking one apart, it was > apparent that they'd used a recovered cell. > > I've no complaints given the price, but be aware that the cell phone packs > may not be new either. > > > On Sun, Jan 22, 2017 at 4:48 PM, Didier Juges wrote: > > > Well worth mentioning that you have found a reputable vendor. I may give > > them a try. > > > > A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 > > vendors picked at semi-random on eBay (4 from each) for evaluation and I > > tested each one of them with a data logger. > > The best one had about half the advertised capacity, the others went down > > from there. Important to observe that none of the set I bought were even > > remotely matched, a crucial consideration if you are going to put them in > > series (a balancer will only ensure your pack is no better than the worst > > cell in the pack). > > Many of the 18650 cells you find on eBay (and maybe other places) are > > actually coming from old laptop battery packs that normally should have > > been discarded/recycled. > > > > In my anticipated application, I only needed one cell (to be followed by > a > > small boost converter), so the issue of balance and matched set was not > > important, but simply I needed the capacity and none were remotely > > satisfactory. I ended up using cell phone booster packs, since I needed > 5V > > anyway. > > > > > > On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < > > time-nuts@febo.com> wrote: > > > > > I use 4 cell balancing and protection circuits, cost a couple of $ more > > but > > > well worth it, I use holders because of limited availability of cells > > > with straps, but rest assured they are held down (discarded PCB)'s, > > > I on purpose did not get into technical details I was only trying to > > share > > > reliable sources, based on disappointing past experiences. > > > Bert Kehren > > > > > > > > > In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, > > > att...@kinali.ch writes: > > > > > > Hoi Bert, > > > > > > On Sat, 21 Jan 2017 08:08:22 -0500 > > > Bert Kehren via time-nuts wrote: > > > > > > > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain > Rechargeable > > > Battery > > > > INR18650-35E_ > > > > > > > (http://www.ebay.com/itm/112173495496?_trksid=p2060353. > > > m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and > > > good price. These > > > > cells have no protection, which I want, since I will for our > > > applications > > > > stack 4 with a 4 cell controller and in two application also > parallel > > > cells > > > > for a total of 8. I have now completed my tests and concentrate > my > > > > battery work on using these cells. > > > > After having tested 26650 cells with disappointing results my focus > > is > > > on > > > > 18650. I am sure there will be 26650 cells available, but right now > > our > > > > focus is on 18650. > > > > I have no connection in any way with these two sources, but think > it > > > may > > > > be helpful for those that look for batteris and do not want to go > > > through > > > > the process I went through. > >
Re: [time-nuts] Li-ion Battreries
One of my hats is working with a recycler to help them best utilize their input stream of recycled electronics. To that end, I take a lot of things apart, looking for failure mechanisms. This allows me to discover common problems, and to suggest which items are economical to repair, and which aren't. In the course of that activity, I have observed a lot of failed lithium battery packs. The most common failure is due to the pack being allowed to discharge too deeply. The protection electronics is happy to disconnect individual cells when they have reached a safe lowest voltage, which is good, but it doesn't do a very good job of protecting cells that are then left for weeks, months, or years in that discharged state. Eventually the cells self discharge (fueled by the protection circuitry's monitoring circuits) to a point where the protection circuitry won't allow them to be charged anymore. If you catch the packs quickly enough, you can bypass the protection circuitry, and pump some charge directly into the cells to restore function. If you wait too long before restoring the cell, they will often get hot, swell up, catch fire, and sometimes explode. They will also do this if you physically abuse the cells by denting them, heating them too hot, or bending them too far. You have been warned! Once you have a cell that functions properly, but maybe at a reduced capacity, it will continue to work reliably, and will continue to slowly lose capacity, just as a new cell would. -Chuck Harris Adrian Godwin wrote: > Recovered cells aren't only sold through ebay parts adverts - they're also > used for production. I recently bought a few cell phone boosters which > consist of an 18650, a charge circuit and a voltage booster to 5V. > > They were low cost and nicely made with an extruded aluminium case and they > worked very well in my application. But on taking one apart, it was > apparent that they'd used a recovered cell. > > I've no complaints given the price, but be aware that the cell phone packs > may not be new either. > > > On Sun, Jan 22, 2017 at 4:48 PM, Didier Juges wrote: > >> Well worth mentioning that you have found a reputable vendor. I may give >> them a try. >> >> A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 >> vendors picked at semi-random on eBay (4 from each) for evaluation and I >> tested each one of them with a data logger. >> The best one had about half the advertised capacity, the others went down >> from there. Important to observe that none of the set I bought were even >> remotely matched, a crucial consideration if you are going to put them in >> series (a balancer will only ensure your pack is no better than the worst >> cell in the pack). >> Many of the 18650 cells you find on eBay (and maybe other places) are >> actually coming from old laptop battery packs that normally should have >> been discarded/recycled. >> >> In my anticipated application, I only needed one cell (to be followed by a >> small boost converter), so the issue of balance and matched set was not >> important, but simply I needed the capacity and none were remotely >> satisfactory. I ended up using cell phone booster packs, since I needed 5V >> anyway. >> >> >> On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < >> time-nuts@febo.com> wrote: >> >>> I use 4 cell balancing and protection circuits, cost a couple of $ more >> but >>> well worth it, I use holders because of limited availability of cells >>> with straps, but rest assured they are held down (discarded PCB)'s, >>> I on purpose did not get into technical details I was only trying to >> share >>> reliable sources, based on disappointing past experiences. >>> Bert Kehren >>> >>> >>> In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, >>> att...@kinali.ch writes: >>> >>> Hoi Bert, >>> >>> On Sat, 21 Jan 2017 08:08:22 -0500 >>> Bert Kehren via time-nuts wrote: >>> purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable >>> Battery INR18650-35E_ >>> (http://www.ebay.com/itm/112173495496?_trksid=p2060353. >>> m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and >>> good price. These cells have no protection, which I want, since I will for our >>> applications stack 4 with a 4 cell controller and in two application also parallel >>> cells for a total of 8. I have now completed my tests and concentrate my battery work on using these cells. After having tested 26650 cells with disappointing results my focus >> is >>> on 18650. I am sure there will be 26650 cells available, but right now >> our focus is on 18650. I have no connection in any way with these two sources, but think it >>> may be helpful for those that look for batteris and do not want to go >>> through the process I went through. >>> >>> >>> Some small remarks: 18650 is by far the most common form factor >>> of Li-Ion batt
[time-nuts] Li-ion Battreries
I have a LOT of experience in testing and using 18650 cells. It is a horrible place for the un-initiated to be. The market is so saturated with dangerous fakes and inferior, over-speced cells that finding a genuine cell is a vanishingly small probability. Hopefully the seller mentioned before pans out and sticks around. You can be pretty much assured that any no-name Chinese cell will be dangerous crap. Buy a 3000 mAh cell that is really 500 mAh and charge it at the 3000 mAh 1C rate and KERBLOOIE! If you want to buy decent cells from a reputable maker (Samsung, Sony, Panasonic, etc) you have to be certified that you know how to properly build with and use them... and also the minimum order quantity can be over 100,000 pieces. Shop around and you can find sellers of 18650 shrink wrap sleeves for all the major/reputable cells. I have yet to test a Chinese cell that comes even close to its advertised specs. Also probably 90+% of what is offered as genuine name brand cells are fakes. Your best bet for finding a decent cell is to get them from GENUINE laptop packs. That is easier said than done... counterfeit packs are the norm. Also, most newer laptops use packs with pouch cells. 18650's are on the way out for modern machines. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
Recovered cells aren't only sold through ebay parts adverts - they're also used for production. I recently bought a few cell phone boosters which consist of an 18650, a charge circuit and a voltage booster to 5V. They were low cost and nicely made with an extruded aluminium case and they worked very well in my application. But on taking one apart, it was apparent that they'd used a recovered cell. I've no complaints given the price, but be aware that the cell phone packs may not be new either. On Sun, Jan 22, 2017 at 4:48 PM, Didier Juges wrote: > Well worth mentioning that you have found a reputable vendor. I may give > them a try. > > A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 > vendors picked at semi-random on eBay (4 from each) for evaluation and I > tested each one of them with a data logger. > The best one had about half the advertised capacity, the others went down > from there. Important to observe that none of the set I bought were even > remotely matched, a crucial consideration if you are going to put them in > series (a balancer will only ensure your pack is no better than the worst > cell in the pack). > Many of the 18650 cells you find on eBay (and maybe other places) are > actually coming from old laptop battery packs that normally should have > been discarded/recycled. > > In my anticipated application, I only needed one cell (to be followed by a > small boost converter), so the issue of balance and matched set was not > important, but simply I needed the capacity and none were remotely > satisfactory. I ended up using cell phone booster packs, since I needed 5V > anyway. > > > On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < > time-nuts@febo.com> wrote: > > > I use 4 cell balancing and protection circuits, cost a couple of $ more > but > > well worth it, I use holders because of limited availability of cells > > with straps, but rest assured they are held down (discarded PCB)'s, > > I on purpose did not get into technical details I was only trying to > share > > reliable sources, based on disappointing past experiences. > > Bert Kehren > > > > > > In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, > > att...@kinali.ch writes: > > > > Hoi Bert, > > > > On Sat, 21 Jan 2017 08:08:22 -0500 > > Bert Kehren via time-nuts wrote: > > > > > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable > > Battery > > > INR18650-35E_ > > > > > (http://www.ebay.com/itm/112173495496?_trksid=p2060353. > > m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and > > good price. These > > > cells have no protection, which I want, since I will for our > > applications > > > stack 4 with a 4 cell controller and in two application also parallel > > cells > > > for a total of 8. I have now completed my tests and concentrate my > > > battery work on using these cells. > > > After having tested 26650 cells with disappointing results my focus > is > > on > > > 18650. I am sure there will be 26650 cells available, but right now > our > > > focus is on 18650. > > > I have no connection in any way with these two sources, but think it > > may > > > be helpful for those that look for batteris and do not want to go > > through > > > the process I went through. > > > > > > Some small remarks: 18650 is by far the most common form factor > > of Li-Ion batteries on the market. This is IMHO the better choice > > than the 26650 if you want to be able to replace them in 10-20 years. > > > > If you stack Li-* batteries, you will need to have a controller that > > monitors each cell individually while charging or has some other means > > of ensuring that none of the cells are overcharged (or rather that they > > are charged the same amount). This kind of circuit is called balancer. > > A protection circuit does _not_ replace a balancer. The protection > circuit > > is only to protect against catastrophic failure. Ie it is still possible > > to overcharge a battery even if it has a protection circuit. You also do > > not know what the protection circuit does to protect the cell. There are > > a lot of chips out there, that simply open a switch and thus disconnect > > the cell. In this case, the protection circuit of one cell will > disconnect > > the whole stack and break charging. > > > > A lot of the multi-cell Li-Ion charger chips have integrated cell > > protection > > circuitry. Ie if you use one of them, you will not need an additional > > protection circuit. But be aware, the regulation for battery protection > > circuit states that the circuit has to be wired fix onto the battery > > in a way that this connection cannot be broken (without breaking the > > housing of the battery pack). The reason for this is, i think, pretty > > obvious. I would recommend that you solder each cell indidividually > > into your circuit instead of using some kind of holder. Or if you are > > using a holder, ma
Re: [time-nuts] Li-ion Battreries
Well worth mentioning that you have found a reputable vendor. I may give them a try. A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 vendors picked at semi-random on eBay (4 from each) for evaluation and I tested each one of them with a data logger. The best one had about half the advertised capacity, the others went down from there. Important to observe that none of the set I bought were even remotely matched, a crucial consideration if you are going to put them in series (a balancer will only ensure your pack is no better than the worst cell in the pack). Many of the 18650 cells you find on eBay (and maybe other places) are actually coming from old laptop battery packs that normally should have been discarded/recycled. In my anticipated application, I only needed one cell (to be followed by a small boost converter), so the issue of balance and matched set was not important, but simply I needed the capacity and none were remotely satisfactory. I ended up using cell phone booster packs, since I needed 5V anyway. On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < time-nuts@febo.com> wrote: > I use 4 cell balancing and protection circuits, cost a couple of $ more but > well worth it, I use holders because of limited availability of cells > with straps, but rest assured they are held down (discarded PCB)'s, > I on purpose did not get into technical details I was only trying to share > reliable sources, based on disappointing past experiences. > Bert Kehren > > > In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, > att...@kinali.ch writes: > > Hoi Bert, > > On Sat, 21 Jan 2017 08:08:22 -0500 > Bert Kehren via time-nuts wrote: > > > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable > Battery > > INR18650-35E_ > > > (http://www.ebay.com/itm/112173495496?_trksid=p2060353. > m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and > good price. These > > cells have no protection, which I want, since I will for our > applications > > stack 4 with a 4 cell controller and in two application also parallel > cells > > for a total of 8. I have now completed my tests and concentrate my > > battery work on using these cells. > > After having tested 26650 cells with disappointing results my focus is > on > > 18650. I am sure there will be 26650 cells available, but right now our > > focus is on 18650. > > I have no connection in any way with these two sources, but think it > may > > be helpful for those that look for batteris and do not want to go > through > > the process I went through. > > > Some small remarks: 18650 is by far the most common form factor > of Li-Ion batteries on the market. This is IMHO the better choice > than the 26650 if you want to be able to replace them in 10-20 years. > > If you stack Li-* batteries, you will need to have a controller that > monitors each cell individually while charging or has some other means > of ensuring that none of the cells are overcharged (or rather that they > are charged the same amount). This kind of circuit is called balancer. > A protection circuit does _not_ replace a balancer. The protection circuit > is only to protect against catastrophic failure. Ie it is still possible > to overcharge a battery even if it has a protection circuit. You also do > not know what the protection circuit does to protect the cell. There are > a lot of chips out there, that simply open a switch and thus disconnect > the cell. In this case, the protection circuit of one cell will disconnect > the whole stack and break charging. > > A lot of the multi-cell Li-Ion charger chips have integrated cell > protection > circuitry. Ie if you use one of them, you will not need an additional > protection circuit. But be aware, the regulation for battery protection > circuit states that the circuit has to be wired fix onto the battery > in a way that this connection cannot be broken (without breaking the > housing of the battery pack). The reason for this is, i think, pretty > obvious. I would recommend that you solder each cell indidividually > into your circuit instead of using some kind of holder. Or if you are > using a holder, make it such that there is no chance any of the cells > can be accidentally short circuited. > > Attila Kinali > -- > Malek's Law: > Any simple idea will be worded in the most complicated way. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
Re: [time-nuts] Li-ion Battreries
Just a quiet message that needs to be said: 18650 style LiIon cells are indeed one of the most common styles of LiIon cells, but with their popularity comes a great deal of fraudulent sales activity. The 18650 cells are used in all sorts of trendy gadgets, like the vape appliences for niccotine addicts, over powered green laser pointers, and vibrators for... well... urhmm...ahhh, I can't say. I went on a quest to try to buy 18650 cells for cheap prices, and then tested them on my Christie CASP battery charger/tester, and I found that I could buy the things wrapped with the labels of Samsung, Sanyo, UltraFire, PowerSonic, and probably a dozen other brands, labeled with 3000 through 9800mAH capacities. In testing, I found two things. If the batteries came from eBay, or Amazon, they would weigh between 1/3 and 1/2 as much as the manufacturer's spec sheets said they would, and they would test at between 400 and 500mAH. And that was with allowing them to discharge until their internal protection circuitry shut them down... in other words to an unsafe level. So, the moral of my story is know your sources, and do test every one... a twist on the old saying: Don't trust but verify. I quit the project, as I feared that the high number of items I was declaring as counterfeit for refund, would soon catch up with me and render me unfit for ebay and Amazon purchases. The safest, surest supply I have found is discarded laptop batteries for Dell computers. Bust them apart, and you will find that all but one of the cells is in good condition. The one bad cell can almost always be resurrected by charging it manually to 4.2V at less than 1C current. Note, they won't have the protection circuitry installed as part of the cell, but you can buy that part on eBay with pretty good results.. -Chuck Harris Attila Kinali wrote: > Hoi Bert, > Some small remarks: 18650 is by far the most common form factor > of Li-Ion batteries on the market. This is IMHO the better choice > than the 26650 if you want to be able to replace them in 10-20 years. > > If you stack Li-* batteries, you will need to have a controller that > monitors each cell individually while charging or has some other means > of ensuring that none of the cells are overcharged (or rather that they > are charged the same amount). This kind of circuit is called balancer. > A protection circuit does _not_ replace a balancer. The protection circuit > is only to protect against catastrophic failure. Ie it is still possible > to overcharge a battery even if it has a protection circuit. You also do > not know what the protection circuit does to protect the cell. There are > a lot of chips out there, that simply open a switch and thus disconnect > the cell. In this case, the protection circuit of one cell will disconnect > the whole stack and break charging. > > A lot of the multi-cell Li-Ion charger chips have integrated cell protection > circuitry. Ie if you use one of them, you will not need an additional > protection circuit. But be aware, the regulation for battery protection > circuit states that the circuit has to be wired fix onto the battery > in a way that this connection cannot be broken (without breaking the > housing of the battery pack). The reason for this is, i think, pretty > obvious. I would recommend that you solder each cell indidividually > into your circuit instead of using some kind of holder. Or if you are > using a holder, make it such that there is no chance any of the cells > can be accidentally short circuited. > > Attila Kinali > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
I use 4 cell balancing and protection circuits, cost a couple of $ more but well worth it, I use holders because of limited availability of cells with straps, but rest assured they are held down (discarded PCB)'s, I on purpose did not get into technical details I was only trying to share reliable sources, based on disappointing past experiences. Bert Kehren In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, att...@kinali.ch writes: Hoi Bert, On Sat, 21 Jan 2017 08:08:22 -0500 Bert Kehren via time-nuts wrote: > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable Battery > INR18650-35E_ > (http://www.ebay.com/itm/112173495496?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and good price. These > cells have no protection, which I want, since I will for our applications > stack 4 with a 4 cell controller and in two application also parallel cells > for a total of 8. I have now completed my tests and concentrate my > battery work on using these cells. > After having tested 26650 cells with disappointing results my focus is on > 18650. I am sure there will be 26650 cells available, but right now our > focus is on 18650. > I have no connection in any way with these two sources, but think it may > be helpful for those that look for batteris and do not want to go through > the process I went through. Some small remarks: 18650 is by far the most common form factor of Li-Ion batteries on the market. This is IMHO the better choice than the 26650 if you want to be able to replace them in 10-20 years. If you stack Li-* batteries, you will need to have a controller that monitors each cell individually while charging or has some other means of ensuring that none of the cells are overcharged (or rather that they are charged the same amount). This kind of circuit is called balancer. A protection circuit does _not_ replace a balancer. The protection circuit is only to protect against catastrophic failure. Ie it is still possible to overcharge a battery even if it has a protection circuit. You also do not know what the protection circuit does to protect the cell. There are a lot of chips out there, that simply open a switch and thus disconnect the cell. In this case, the protection circuit of one cell will disconnect the whole stack and break charging. A lot of the multi-cell Li-Ion charger chips have integrated cell protection circuitry. Ie if you use one of them, you will not need an additional protection circuit. But be aware, the regulation for battery protection circuit states that the circuit has to be wired fix onto the battery in a way that this connection cannot be broken (without breaking the housing of the battery pack). The reason for this is, i think, pretty obvious. I would recommend that you solder each cell indidividually into your circuit instead of using some kind of holder. Or if you are using a holder, make it such that there is no chance any of the cells can be accidentally short circuited. Attila Kinali -- Malek's Law: Any simple idea will be worded in the most complicated way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Li-ion Battreries
Hoi Bert, On Sat, 21 Jan 2017 08:08:22 -0500 Bert Kehren via time-nuts wrote: > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable Battery > > INR18650-35E_ > (http://www.ebay.com/itm/112173495496?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT) > for two reason 10 A load and good price. These > cells have no protection, which I want, since I will for our applications > stack 4 with a 4 cell controller and in two application also parallel cells > for a total of 8. I have now completed my tests and concentrate my > battery work on using these cells. > After having tested 26650 cells with disappointing results my focus is on > 18650. I am sure there will be 26650 cells available, but right now our > focus is on 18650. > I have no connection in any way with these two sources, but think it may > be helpful for those that look for batteris and do not want to go through > the process I went through. Some small remarks: 18650 is by far the most common form factor of Li-Ion batteries on the market. This is IMHO the better choice than the 26650 if you want to be able to replace them in 10-20 years. If you stack Li-* batteries, you will need to have a controller that monitors each cell individually while charging or has some other means of ensuring that none of the cells are overcharged (or rather that they are charged the same amount). This kind of circuit is called balancer. A protection circuit does _not_ replace a balancer. The protection circuit is only to protect against catastrophic failure. Ie it is still possible to overcharge a battery even if it has a protection circuit. You also do not know what the protection circuit does to protect the cell. There are a lot of chips out there, that simply open a switch and thus disconnect the cell. In this case, the protection circuit of one cell will disconnect the whole stack and break charging. A lot of the multi-cell Li-Ion charger chips have integrated cell protection circuitry. Ie if you use one of them, you will not need an additional protection circuit. But be aware, the regulation for battery protection circuit states that the circuit has to be wired fix onto the battery in a way that this connection cannot be broken (without breaking the housing of the battery pack). The reason for this is, i think, pretty obvious. I would recommend that you solder each cell indidividually into your circuit instead of using some kind of holder. Or if you are using a holder, make it such that there is no chance any of the cells can be accidentally short circuited. Attila Kinali -- Malek's Law: Any simple idea will be worded in the most complicated way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Li-ion Battreries
In the seventies I used F size NiCad’s in applications like OCXO’s later Rb’s for power backups. Later switched to Ni-MH in all cases needed complex charge control and cutout to protect batteries. Today I have switched to Li-ion mainly because of the low cost reliable power management including protection of the cells. The repeated problem has been a reliable source. Over the last couple of years I have spend more than $ 300 only to get most the time junk, no real reliable sources. That has changed. Fasttech does offer cells that they have tested and is a source for those living outside the US. Even though they claim shipping free once you go to checkout you get hit with $ 29 shipping. After multiple trials I finally found a perfect US source. _genuinecells_ (http://myworld.ebay.com/genuinecells) is located in Florida and my thought was if disappointed I could afford to ship back. Gen responded to my request for information with data sheets and additional information. I purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable Battery INR18650-35E_ (http://www.ebay.com/itm/112173495496?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT) for two reason 10 A load and good price. These cells have no protection, which I want, since I will for our applications stack 4 with a 4 cell controller and in two application also parallel cells for a total of 8. I have now completed my tests and concentrate my battery work on using these cells. After having tested 26650 cells with disappointing results my focus is on 18650. I am sure there will be 26650 cells available, but right now our focus is on 18650. I have no connection in any way with these two sources, but think it may be helpful for those that look for batteris and do not want to go through the process I went through. Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
