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#82
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Lithium Ion vs NiMh battery
On Friday, October 27, 2017 at 4:45:33 PM UTC-7, Joerg wrote:
On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator and some digital thermometers that use the same sort of battery, type 357. All those devices are from the 80's and are now on the 2nd set of batteries. Joerg - you're a hoarder aren't you? What else would ever lead you to think that I would keep the packaging on batteries after installing them? |
#83
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Lithium Ion vs NiMh battery
On Friday, October 27, 2017 at 6:27:05 PM UTC-7, Frank Krygowski wrote:
On 10/27/2017 7:45 PM, Joerg wrote: On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator... Damn, I still miss mine. Even though I've got an HP48G sitting in front of me. The heck of it is, the twerp that stole the 11C doubtlessly never figured out how to use it. -- - Frank Krygowski Calculator and converter: Version 10.1709.2703.0 © 2017 Microsoft Corporation. All rights reserved. |
#84
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Lithium Ion vs NiMh battery
On 10/23/2017 9:37 AM, Jeff Liebermann wrote:
On Mon, 23 Oct 2017 08:06:07 -0700, sms wrote: On 10/22/2017 8:13 PM, Jeff Liebermann wrote: I recently bought a few of the lowest priced 18650 on eBay. Garbage in, lumens out. These were suppose to be 5800 and 5000 ma-hr but delivered 1000 and 880 ma-hr: http://802.11junk.com/jeffl/battery-tests/18650.jpg After about 10 charge/discharge cycles, the 5000 ma-hr cell is showing signs impending failure. Oh please, did you really expect 5800 mAH from an 18650? There is no such thing! Of course not. Notice that I said "bought a few of the lowest priced 18650 on eBay". I wanted to see how the worst possible cells preformed. These seem to be a fairly reasonable proposition. I haven't massaged the numbers quite yet, but it seems that a $1 junk 18650 battery, that produces about 1000 ma-hr capacity, has a lower cost of ownership than a $5 cell 2500 ma-hr from a reputable vendor. If I buy only junk batteries, I would get twice the capacity for the same cost, if I'm willing to ride with a bag full of spare batteries. However, early results from repeated charge/discharge cycles is showing that the junk cells don't last. The cheapest way to buy flat top 18650 cells is to buy one of those USB battery packs. Fry's has a 16,800 mAH model comprised of six 2800mAH 18650 cells for $17. That's $2.83 per cell. For button-top cells, the source that Barry Beams provided is probably the best option. I.e. for button-top https://liionwholesale.com/collections/batteries/products/protected-panasonic-ncr18650b-3400mah-li-ion-18650-button-top-battery?variant=1925834564. The prices are certainly tolerable, but only if the batteries are not counterfeit. That's the problem I had buying on eBay. I bought a few odd high priced cells, that were suppose to be name brand cells, and ended up with counterfeits. Of course, when I complained, the vendors refunded my money and claimed they didn't know that they were counterfeit. Incidentally, I usually weigh my 18650 cells. For a good battery, I usually end up with 45 grams/cell. One of the aforementioned batteries weighted an amazing 72 grams, was advertised as 3500 ma-hr and measured 800 ma-hr. I couldn't resist opening it up. Inside, I found what looked like the guts from a 14500 cell and a mixture of sand and wax to increase the weight. Another oddity is while 18650 cells are often market with wildly optimistic ma-hr ratings (much like flashlight lumens), other size LiIon cells seems to be marked with more realistic ratings. For example, I bought a pile of SkyWolfEye 14500 (AA size) cells marked 1200 ma-hr. They measure about 1100 ma-hr when tested at the industry standard 0.2C constant current discharge rate. However, at the 1A discharge, where I plan to use these cells, the best they could do is about 450 ma-hr. Still, if you use common 0.2C test method, they almost meet their advertised spec. I have a 2 x 18650 powerbank that is rated at 6000mAH (printed on the case so you know it's true) https://adreama.com/product/powerbank-xxx-mah-712411984410/, It popped open so I looked at the batteries inside, 2200mAH each. Allowing for the typical mAH inflation of no-name batteries, I suspect that the actual capacity is about 3200mAH |
#85
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Lithium Ion vs NiMh battery
On Monday, October 30, 2017 at 8:20:32 AM UTC-7, sms wrote:
On 10/23/2017 9:37 AM, Jeff Liebermann wrote: On Mon, 23 Oct 2017 08:06:07 -0700, sms wrote: On 10/22/2017 8:13 PM, Jeff Liebermann wrote: I recently bought a few of the lowest priced 18650 on eBay. Garbage in, lumens out. These were suppose to be 5800 and 5000 ma-hr but delivered 1000 and 880 ma-hr: http://802.11junk.com/jeffl/battery-tests/18650.jpg After about 10 charge/discharge cycles, the 5000 ma-hr cell is showing signs impending failure. Oh please, did you really expect 5800 mAH from an 18650? There is no such thing! Of course not. Notice that I said "bought a few of the lowest priced 18650 on eBay". I wanted to see how the worst possible cells preformed. These seem to be a fairly reasonable proposition. I haven't massaged the numbers quite yet, but it seems that a $1 junk 18650 battery, that produces about 1000 ma-hr capacity, has a lower cost of ownership than a $5 cell 2500 ma-hr from a reputable vendor. If I buy only junk batteries, I would get twice the capacity for the same cost, if I'm willing to ride with a bag full of spare batteries. However, early results from repeated charge/discharge cycles is showing that the junk cells don't last. The cheapest way to buy flat top 18650 cells is to buy one of those USB battery packs. Fry's has a 16,800 mAH model comprised of six 2800mAH 18650 cells for $17. That's $2.83 per cell. For button-top cells, the source that Barry Beams provided is probably the best option. I.e. for button-top https://liionwholesale.com/collections/batteries/products/protected-panasonic-ncr18650b-3400mah-li-ion-18650-button-top-battery?variant=1925834564. The prices are certainly tolerable, but only if the batteries are not counterfeit. That's the problem I had buying on eBay. I bought a few odd high priced cells, that were suppose to be name brand cells, and ended up with counterfeits. Of course, when I complained, the vendors refunded my money and claimed they didn't know that they were counterfeit. Incidentally, I usually weigh my 18650 cells. For a good battery, I usually end up with 45 grams/cell. One of the aforementioned batteries weighted an amazing 72 grams, was advertised as 3500 ma-hr and measured 800 ma-hr. I couldn't resist opening it up. Inside, I found what looked like the guts from a 14500 cell and a mixture of sand and wax to increase the weight. Another oddity is while 18650 cells are often market with wildly optimistic ma-hr ratings (much like flashlight lumens), other size LiIon cells seems to be marked with more realistic ratings. For example, I bought a pile of SkyWolfEye 14500 (AA size) cells marked 1200 ma-hr. They measure about 1100 ma-hr when tested at the industry standard 0.2C constant current discharge rate. However, at the 1A discharge, where I plan to use these cells, the best they could do is about 450 ma-hr. Still, if you use common 0.2C test method, they almost meet their advertised spec. I have a 2 x 18650 powerbank that is rated at 6000mAH (printed on the case so you know it's true) https://adreama.com/product/powerbank-xxx-mah-712411984410/, It popped open so I looked at the batteries inside, 2200mAH each. Allowing for the typical mAH inflation of no-name batteries, I suspect that the actual capacity is about 3200mAH I have a Li-ion 1500 mAh for my camera and a spare. They don't hold charges very long so I usually charge them up before serious use. |
#86
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Lithium Ion vs NiMh battery
On 2017-10-29 13:49, wrote:
On Friday, October 27, 2017 at 4:45:33 PM UTC-7, Joerg wrote: On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator and some digital thermometers that use the same sort of battery, type 357. All those devices are from the 80's and are now on the 2nd set of batteries. Joerg - you're a hoarder aren't you? What else would ever lead you to think that I would keep the packaging on batteries after installing them? I have a battery drawer and this contains various types of batteries in cartons, blister packs and whatnot. Those have the date codes and "use by" years. If a battery gets installed in a device where many years of life are expected I write that on a snippet of adhesive-backed paper and stick it on the back of the device. This also (mostly) prevents the dreaded situation where a battery that still has enough juice has started leaking. Other stuff is on a checklist. Smoke alarms, CO sensors, remotes, gear where batteries can leak, and so on. I am a strong believer in checklists. Even got one for my beer brewing. -- Regards, Joerg http://www.analogconsultants.com/ |
#87
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Lithium Ion vs NiMh battery
On 2017-10-27 18:27, Frank Krygowski wrote:
On 10/27/2017 7:45 PM, Joerg wrote: On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator... Damn, I still miss mine. Even though I've got an HP48G sitting in front of me. The heck of it is, the twerp that stole the 11C doubtlessly never figured out how to use it. Not all hope is lost: https://www.ebay.com/itm/Hewlett-Pac...g/152756750101 If in a rush the "buy it now" deals go for $80-$120. There used to be an anniversary edition but only for the HP-12C which is the financial version. Use engineers need the 1e-3 notation and all that. -- Regards, Joerg http://www.analogconsultants.com/ |
#88
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Lithium Ion vs NiMh battery
On Mon, 30 Oct 2017 08:20:29 -0700, sms
wrote: I have a 2 x 18650 powerbank that is rated at 6000mAH (printed on the case so you know it's true) https://adreama.com/product/powerbank-xxx-mah-712411984410/ That would be 3000ma-hr rated capacity per cell. That's not going to happen. See below. It popped open I translate that to mean it fell apart. so I looked at the batteries inside, 2200mAH each. Allowing for the typical mAH inflation of no-name batteries, I suspect that the actual capacity is about 3200mAH I agree with your estimate. Most of the generic cell's I've tested end up around 1600 ma-hr (or 3200 ma-hr for your "powerbank"). To the best of my limited knowledge, the largest capacity 18650 cell is the Panasonic NCR18650G at 3400 ma-hr https://na.industrial.panasonic.com/sites/default/pidsa/files/ncr18650b.pdf or maybe the LG MJ1 at 3500 ma-hr: https://www.nkon.nl/sk/k/Specification%20INR18650MJ1%2022.08.2014.pdf The problem is that batteries are tested at a discharge current of 0.2C. For the LG MJ1, that would be: 0.2 * 3500 = 700 ma That's actually fairly close to the current drain of most 2 LED headlights. Assuming about 75 lumens/watt: 3.6V * 0.7A * 75 lumens/watt = 189 lumens If you look at the bottom end of the 18650 market, the cells seems to test at about 1200 ma-hr. The 0.2C discharge test would be done at: 0.2 * 1200 = 240 ma If you take the same headlight as the LG MJ1 test, it would be testing a mythical headlight producing only: 3.6v * 0.24A * 75 lumens/watt = 65 lumens That's not counting the decrease in capacity at higher currents for this 18650 cell. This all would be easy if different size batteries were tested at some standard discharge current, so that it would be possible to better compare cells, but's that's not going to happen. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#89
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Lithium Ion vs NiMh battery
On 10/30/2017 7:11 PM, Joerg wrote:
On 2017-10-27 18:27, Frank Krygowski wrote: On 10/27/2017 7:45 PM, Joerg wrote: On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator... Damn, I still miss mine. Even though I've got an HP48G sitting in front of me. The heck of it is, the twerp that stole the 11C doubtlessly never figured out how to use it. Not all hope is lost: https://www.ebay.com/itm/Hewlett-Pac...g/152756750101 I know they pop up there. I don't bid because the company I was working for at the time bought me a replacement, an HP32S-II. That now lives in my workshop. And as I said, I've also got the HP48G. Since I'm retired, it would be silly to buy another 11C. Even though it really was my favorite. -- - Frank Krygowski |
#90
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Lithium Ion vs NiMh battery
On Mon, 30 Oct 2017 23:31:18 -0400, Frank Krygowski
wrote: On 10/30/2017 7:11 PM, Joerg wrote: On 2017-10-27 18:27, Frank Krygowski wrote: On 10/27/2017 7:45 PM, Joerg wrote: On 2017-10-27 16:19, wrote: On Friday, October 27, 2017 at 9:35:01 AM UTC-7, Joerg wrote: On 2017-10-27 08:37, wrote: On Friday, October 27, 2017 at 2:10:50 AM UTC-7, John B. wrote: On Wed, 25 Oct 2017 09:34:38 -0700 (PDT), wrote: On Tuesday, October 24, 2017 at 6:09:13 PM UTC-7, John B. wrote: Which brings up something I've always wondered about. You go in the store and there is a very nice battery display rack with all sorts of batteries. One can only speculate how long they have been on the rack, or in storage before being displayed on the rack. Does the store scrap any battery that has been on the rack for X months? Years? Or just keep them until someone buys them? And which brings up another question - how do you know that your source is any better? I don't. In fact I don't even worry about the price of a small battery. It was just something that came to mind the other day while I was waiting in line at Home Pro. Right there by the cash register they had a big rack of batteries, must have been a hundred of them. I came across a pile of dead batteries that I had saved when I was trying to be green before I learned that I had to drive five miles to dispose of these button cells. They were Sony and something called Renata. I didn't find any of those Panasonic but the sheet they come on is unmistakable. I remember tearing the last two out of that sheet to try to use in the transmitter unit only to discover them dead. What was the expiration year on those? Hell if I know. On the non-writing side there is a 72 on one and a 58 on the other. Since they weren't made in those years that sure couldn't be an expiration date. It's on the back of the package, a "Use by" date: https://images-na.ssl-images-amazon....L._SL1500_.jpg What impresses the heck out of me is the HP-11C pocket calculator... Damn, I still miss mine. Even though I've got an HP48G sitting in front of me. The heck of it is, the twerp that stole the 11C doubtlessly never figured out how to use it. Not all hope is lost: https://www.ebay.com/itm/Hewlett-Pac...g/152756750101 I know they pop up there. I don't bid because the company I was working for at the time bought me a replacement, an HP32S-II. That now lives in my workshop. And as I said, I've also got the HP48G. Since I'm retired, it would be silly to buy another 11C. Even though it really was my favorite. A friend at work had one of those H.P. calculators and I found the reverse polish notation to almost impossible to work with. An eccentricity perhaps but " 3 4 5 × - " just didn't seem logical :-) -- Cheers, John B. |
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