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#12
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LiFePO4 chargers
On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote:
On 11/4/18 3:51 PM, wrote: On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote: I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in. Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway. Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging. I would hope they're safer than something like a li-po, model airplanes using those things routinely put on a fireworks display during a crash. Fascinating videos on YouTube. However, "safer" isn't actually the same as "safe", LFP's are quite capable of burning, despite what the scholarly articles say. There have been a number of fires, particularly when they're used as starter batteries. High charge rates and very high discharge rates seem to cause problems, as homebuilders of small power planes have discovered. There was also that LFP battery fire in an EB-28 in Finland this summer. -Dave Dave, if you look around youtube long enough, you will find that a AAA battery can make a fire. Certainly a 12V lead-acid has enough juice to do that if circumstances are right. The overwhelming evidence of many years of usage of LiFePo4 chemistry in glider batteries suggests that they are as safe as the old gel-cells. Give progress a chance, I'm not saying be a Progressive. Herb |
#13
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LiFePO4 chargers
Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites.
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#14
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LiFePO4 chargers
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#15
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LiFePO4 chargers
On 11/11/18 7:02 AM, wrote:
On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote: On 11/4/18 3:51 PM, wrote: On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote: I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in. Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway. Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging. I would hope they're safer than something like a li-po, model airplanes using those things routinely put on a fireworks display during a crash. Fascinating videos on YouTube. However, "safer" isn't actually the same as "safe", LFP's are quite capable of burning, despite what the scholarly articles say. There have been a number of fires, particularly when they're used as starter batteries. High charge rates and very high discharge rates seem to cause problems, as homebuilders of small power planes have discovered. There was also that LFP battery fire in an EB-28 in Finland this summer. -Dave Dave, if you look around youtube long enough, you will find that a AAA battery can make a fire. Certainly a 12V lead-acid has enough juice to do that if circumstances are right. The overwhelming evidence of many years of usage of LiFePo4 chemistry in glider batteries suggests that they are as safe as the old gel-cells. Give progress a chance, I'm not saying be a Progressive. Herb If you come across a YouTube video of an AAA battery filling a cockpit with toxic smoke, you be sure to post the link, OK? Meanwhile, this is the sort of progress I can live without: https://www.pilotsofamerica.com/comm...-fires.102016/ -Dave |
#16
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LiFePO4 chargers
Not all LifePo4 battery chemistry is the same. When I fitted 2 LifePO4
batteries to my 27 I chose A123 because of their chemistry and BMC. See he https://tinyurl.com/ybmof8qh Unfortunately theses batteries were only 4.5AH but because of the way the voltage stays good until the BMC shuts the battery down I have never run out of power. Also unfortunately, I am not sure that the 12V7 form factor is still available so I am hoping that the rated 5000 cycles will see me out! Jim |
#17
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LiFePO4 chargers
The original poster called the battery a "Lithium Iron".Â* Later on in
the thread someone said, "Lithium Ion".Â* Which is it?Â* I haven't yet heard of a Lithium Iron Phosphate (LiFePO4) battery causing a problem.Â* Stemme installs LiFePO4 batteries in the S-12 new from the factory. On 11/13/2018 9:18 PM, kinsell wrote: On 11/11/18 7:02 AM, wrote: On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote: On 11/4/18 3:51 PM, wrote: On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote: I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in. Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway. Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging. I would hope they're safer than something like a li-po, model airplanes using those things routinely put on a fireworks display during a crash. Fascinating videos on YouTube. However, "safer" isn't actually the same as "safe", LFP's are quite capable of burning, despite what the scholarly articles say. There have been a number of fires, particularly when they're used as starter batteries.Â* High charge rates and very high discharge rates seem to cause problems, as homebuilders of small power planes have discovered. There was also that LFP battery fire in an EB-28 in Finland this summer. -Dave Dave, if you look around youtube long enough, you will find that a AAA battery can make a fire. Certainly a 12V lead-acid has enough juice to do that if circumstances are right. The overwhelming evidence of many years of usage of LiFePo4 chemistry in glider batteries suggests that they are as safe as the old gel-cells. Give progress a chance, I'm not saying be a Progressive. Herb If you come across a YouTube video of an AAA battery filling a cockpit with toxic smoke, you be sure to post the link, OK? Meanwhile, this is the sort of progress I can live without: https://www.pilotsofamerica.com/comm...-fires.102016/ -Dave -- Dan, 5J |
#18
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LiFePO4 chargers
On Tuesday, November 13, 2018 at 11:11:52 PM UTC-5, kinsell wrote:
On 11/13/18 6:08 PM, bruce... wrote: Mark, When K2 was fairly new on the market I contacted them asking if Battery Tender Jr. is okay and safe, they replied that it is perfectly okay and nearly the same as their charger. I also contacted Battery Tender Jr. with the reverse question and they said the BTJr is fine for LiFePO4. I used the BTJr for years on my K2 with no issues. They're about $25 on internet sites. Have you measured the amount of charge you're getting into the K2's? It will be considerably less than the rated amount due to using a lead-acid charger. Also, if K2 has cell balancing capability, it won't be used because your Battery Tender doesn't put out enough voltage to make it work. Many simple lead-acid chargers reach up to around 14.2-14.8 volts. That voltage would suffice to charge an LFP battery to well above 90% capacity if it stays there for a while. If it quickly shifts to "float" at 13.5V or so then it won't do well in charging LFP. So simpler is better in this case. Measure what your charger does. And disconnect it after several hours, don't leave it on "float". |
#19
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LiFePO4 chargers
On Tuesday, November 13, 2018 at 10:19:34 PM UTC-6, kinsell wrote:
On 11/11/18 7:02 AM, wrote: On Saturday, November 10, 2018 at 12:03:42 AM UTC-6, kinsell wrote: On 11/4/18 3:51 PM, wrote: On Monday, November 5, 2018 at 8:02:04 AM UTC+10, wrote: I also have heard the stories about fires while charging, but, as far as I know, most involved a different Lithium chemistry (Li-ion, Li-Polymer etc.) LiFePO4 is supposed to be safer, but by how much I do not know. At any rate, I am pretty much stuck with charging them in the plane, as they are mounted well behind the spar, and it takes a good 20-30 minutes to get them out and put them back in. Here is an FAA report that supports the assertion that LiFePO4 cells are safer: https://www.fire.tc.faa.gov/pdf/TC-16-17.pdf In their testing, which they admit had quite variable results, they did not get any thermal runaway with LiFePO4 cells, but did with all the other Li chemistries they tested. Note that the graphs in the above article show 1 cell out of 5 consumed by "thermal runaway" but that was the cell that they were heating externally to try and initiate the runaway. Not to say that you shouldn't take precautions, all battery chemistries store enough energy to start an electrical fire, even if they are relatively immune to thermal runaway and overcharging. I would hope they're safer than something like a li-po, model airplanes using those things routinely put on a fireworks display during a crash.. Fascinating videos on YouTube. However, "safer" isn't actually the same as "safe", LFP's are quite capable of burning, despite what the scholarly articles say. There have been a number of fires, particularly when they're used as starter batteries. High charge rates and very high discharge rates seem to cause problems, as homebuilders of small power planes have discovered. There was also that LFP battery fire in an EB-28 in Finland this summer. |
#20
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LiFePO4 chargers
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