LiFePO4 chargers

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.

Thanks for the link to the FAA test. I picked up one conclusion that made reading the whole thing worthwhile, even though I am not an Electrical Engineer and do not claim to understand the report completely:

"In general, of all of the lithium-ion cells that were tested, LiFePO4 would be considered the safest cathode material because of the relatively low temperature rise and the resulting low likelihood for thermal runaway to propagate. LiCoO2 and LiMnNi would be considered the most hazardous because of the relatively large temperature rise and high probability for propagation of thermal runaway to adjacent battery cells."

Once again, thanks for the link.

You should take a look at the CTEK Lithium US charger.
Fully automatic.
Performs battery testing.
Can leave on float.

+1 on the CTEK LiFePO4 charger. Not cheap, but it has several charging stages that really do stuff the battery full of charge - and much cheaper than buying new LiFePO4s.

The first few times I charged up my K2s (previously charged with a Fuyuang 14.6 Li-ion) it took some hours to step through the charging stages. The manual explains the charging stages.

I ran one battery over three extended flights and the voltage stayed up. The Air Glide S shows the voltage dropping 0.1 or 0.2 V; then coming back up a number of times. The BMS is on top of the job.

Thanks for the report. As I recall the FAA is also tracking battery fire incidents of various Lithium Ion types and I don't ever recall mention of LifePo4 variant at least in commercially reported cases.

For chargers, RC community would probably agree Hyperion are excellent.. whether the battery has or doesn't have BMS. And I also like Hitec for the ability to use a thermal sensor during charge for emergency shutoff.

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

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

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

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

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