If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Battery safety (againish)
kinsell wrote on 3/16/2019 9:46 PM:
Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.* Is that a problem?* Or is the location of the batteries in this specific glider such that the resin is advisable?* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm http://soaringsafety.org/prevention/...anes-2014A.pdf |
#12
|
|||
|
|||
Battery safety (againish)
I used LiFePO4 batteries in my former LAK-17a for about 3 years before
selling the glider.Â* I charged them out of the glider for the first year and, thereafter, left them on the provided smart chargers in the glider between flights.Â* They had battery management systems built-in.Â* Of course, there's practically no vibration in a pure glider... On 3/17/2019 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem?Â* Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic.Â* OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned. There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. -- Dan, 5J |
#13
|
|||
|
|||
Battery safety (againish)
On Monday, March 18, 2019 at 8:22:43 AM UTC-7, Dan Marotta wrote:
I used LiFePO4 batteries in my former LAK-17a for about 3 years before selling the glider.Â* I charged them out of the glider for the first year and, thereafter, left them on the provided smart chargers in the glider between flights.Â* They had battery management systems built-in.Â* Of course, there's practically no vibration in a pure glider... On 3/17/2019 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem?Â* Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic.Â* OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned. There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. -- Dan, 5J Of all of the articles and papers I have read on rechargeable batteries, this is the first one that talked about modifying the internal construction of the battery. The mere idea of drilling into a battery scares the hell out of me, and I bet it would do the same to the manufacturer. Tom |
#14
|
|||
|
|||
Battery safety (againish)
I cut one of my K2 batteries open, after one of the cells in it failed. There's not a lot of space available in there for foam, or drill bits.
-nick one of the cells with a drill and it's going to be bad. -Equal foam filling is unlikely -Good possibility of the foam compressing the cells or expanding the case. -The foam is going to interfere with heat dissipation in a big way, its a pretty good insulator. -When chasing vibration issues, sometimes tightening up the system makes things worse not better. -LiFePO batteries don't supply their own oxidizer in a fire, No one ever said they wouldn't catch on fire. Just if they do, they can be put out by depriving them of oxygen. Unlike Lithium ion chemistry batteries which supply their own oxidizer if they catch on fire. So the LiFePO batteries are considered to be a safer battery chemistry, but not a completely safe battery.. A plastic box full of lead plates submerged in sulfuric acid isn't completely safe either. A LiFePO battery(s) with an internal BMS board, with a fuse right at the battery is the way to go, but treat it with the respect that that much energy stored in a small package deserves. SF |
#15
|
|||
|
|||
Battery safety (againish)
On Saturday, March 16, 2019 at 7:23:21 PM UTC-7, Jonathan St. Cloud wrote:
On Saturday, March 16, 2019 at 4:35:22 PM UTC-7, kinsell wrote: On 3/16/19 1:10 PM, Andrzej Kobus wrote: On Saturday, March 16, 2019 at 1:04:19 PM UTC-4, kinsell wrote: On 3/16/19 10:05 AM, Jonathan St. Cloud wrote: Was wondering if others had read and were doing this: https://www.dg-flugzeugbau.de/wp-con...2019-103-e.pdf The ASG-29E has a gas tank directly above two batteries used to power flight instruments. Interesting that they say to add epoxy to the casing. Putting a fuse at one of the battery terminals would be a more conventional way of handling it, and would allow for easier battery replacement. You are missing the point. The fuse will not protect against internal short. No, not missing the point. The way I read it, they're talking about an battery holder added around the battery. You wouldn't normally call internal wiring "battery cables". Maybe something got lost in translation. If anybody is using a battery so poorly constructed that it shorts out internally and catches fire, that battery should be discarded immediately. The way I read it is a small hole is drilled in the case and resin injected...? No. Bulletin is suggesting all work is done by the battery manufacturer(Accu-24). |
#16
|
|||
|
|||
Battery safety (againish)
On 3/17/19 9:54 PM, Eric Greenwell wrote:
kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem? Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.Â* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. Yes, EarthX is well regarded in the homebuilt powerplane world. Dual redundant BMS boards to make you feel good. Here's a greatpicture of one: http://www.avidfoxflyers.com/index.p...ttery-warning/ If you poke around, there's a nice video from the Director of Engineering at EarthX, he talks about the requirement to have a gas-tight battery box vented to the outside, to use only a three-phase alternator to charge it, and to add a crowbar circuit to prevent over-voltage. Wonder how many glider pilots go to all this trouble? I think I'll stick to SLA, just press the button and the engine starts in about a second. -Dave P.S. That StewartB in the original thread was a real hoot. Said he worried more about getting mad cow disease than having trouble with his EarthX battery. Until his battery went bad. Don't know if he still eats hamburgers or not. |
#17
|
|||
|
|||
Battery safety (againish)
On Tuesday, March 19, 2019 at 10:04:00 PM UTC-7, kinsell wrote:
On 3/17/19 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem? Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.Â* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. Yes, EarthX is well regarded in the homebuilt powerplane world. Dual redundant BMS boards to make you feel good. Here's a greatpicture of one: http://www.avidfoxflyers.com/index.p...ttery-warning/ If you poke around, there's a nice video from the Director of Engineering at EarthX, he talks about the requirement to have a gas-tight battery box vented to the outside, to use only a three-phase alternator to charge it, and to add a crowbar circuit to prevent over-voltage. Wonder how many glider pilots go to all this trouble? I think I'll stick to SLA, just press the button and the engine starts in about a second. -Dave P.S. That StewartB in the original thread was a real hoot. Said he worried more about getting mad cow disease than having trouble with his EarthX battery. Until his battery went bad. Don't know if he still eats hamburgers or not. Dave, Perhaps you could post a link to this video - I could not find it. To the contrary, the video I could find extolled the safety of their batteries in aircraft: https://earthxbatteries.com/product-...ental-aircraft |
#18
|
|||
|
|||
Battery safety (againish)
On 3/22/19 8:23 PM, 2G wrote:
On Tuesday, March 19, 2019 at 10:04:00 PM UTC-7, kinsell wrote: On 3/17/19 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem? Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.Â* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. Yes, EarthX is well regarded in the homebuilt powerplane world. Dual redundant BMS boards to make you feel good. Here's a greatpicture of one: http://www.avidfoxflyers.com/index.p...ttery-warning/ If you poke around, there's a nice video from the Director of Engineering at EarthX, he talks about the requirement to have a gas-tight battery box vented to the outside, to use only a three-phase alternator to charge it, and to add a crowbar circuit to prevent over-voltage. Wonder how many glider pilots go to all this trouble? I think I'll stick to SLA, just press the button and the engine starts in about a second. -Dave P.S. That StewartB in the original thread was a real hoot. Said he worried more about getting mad cow disease than having trouble with his EarthX battery. Until his battery went bad. Don't know if he still eats hamburgers or not. Dave, Perhaps you could post a link to this video - I could not find it. To the contrary, the video I could find extolled the safety of their batteries in aircraft: https://earthxbatteries.com/product-...ental-aircraft That video was in an EAA seminar: http://go.eaa.org/UVqR00U0BE0SOs03oK000hV Some good info on charging systems he https://earthxbatteries.com/engine-c...hium-batteries |
#19
|
|||
|
|||
Battery safety (againish)
On Friday, March 22, 2019 at 9:23:17 PM UTC-7, kinsell wrote:
On 3/22/19 8:23 PM, 2G wrote: On Tuesday, March 19, 2019 at 10:04:00 PM UTC-7, kinsell wrote: On 3/17/19 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem? Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.Â* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. Yes, EarthX is well regarded in the homebuilt powerplane world. Dual redundant BMS boards to make you feel good. Here's a greatpicture of one: http://www.avidfoxflyers.com/index.p...ttery-warning/ If you poke around, there's a nice video from the Director of Engineering at EarthX, he talks about the requirement to have a gas-tight battery box vented to the outside, to use only a three-phase alternator to charge it, and to add a crowbar circuit to prevent over-voltage. Wonder how many glider pilots go to all this trouble? I think I'll stick to SLA, just press the button and the engine starts in about a second. -Dave P.S. That StewartB in the original thread was a real hoot. Said he worried more about getting mad cow disease than having trouble with his EarthX battery. Until his battery went bad. Don't know if he still eats hamburgers or not. Dave, Perhaps you could post a link to this video - I could not find it. To the contrary, the video I could find extolled the safety of their batteries in aircraft: https://earthxbatteries.com/product-...ental-aircraft That video was in an EAA seminar: http://go.eaa.org/UVqR00U0BE0SOs03oK000hV Some good info on charging systems he https://earthxbatteries.com/engine-c...hium-batteries I am confused, is EarthX saying you have to enclose your lithium battery in a sealed box or not? If so, then why don't they say so on their website? |
#20
|
|||
|
|||
Battery safety (againish)
On Saturday, March 23, 2019 at 12:23:17 AM UTC-4, kinsell wrote:
On 3/22/19 8:23 PM, 2G wrote: On Tuesday, March 19, 2019 at 10:04:00 PM UTC-7, kinsell wrote: On 3/17/19 9:54 PM, Eric Greenwell wrote: kinsell wrote on 3/16/2019 9:46 PM: Many of us are flying with multi-cell LiFePO4 batteries that have internal wiring and are not filled with resin.Â* Is that a problem? Or is the location of the batteries in this specific glider such that the resin is advisable?Â* A battery fire anywhere in a glider (even without a fuel tank) is catastrophic. OTOH I havn't heard of any fires with this type of battery.Â* It's the lithium-polymer battery pack (also much larger, with many more cells) in the FES systems that has had fires. Well, the service bulletin talks about an LFP that burned.Â* There was a fire in an EB-28 in Finland last year with a 10 A-H LFP.Â* Here's a video of an LFP burning: https://www.pilotsofamerica.com/comm...-fires.102016/ There have been claims that LFP's don't burn, but that's simply not true. The Aerovoltz battery that burned did not have a BMS; in fact, none of the Aerovoltz batteries have a BMS (battery management system). I would not want to use one, even though the short engine runs typical of self-launchers means problems would be less likely than in airplanes. The Earth-X batteries all have a BMS, seem better characterized, and I would trust them a lot more. Yes, EarthX is well regarded in the homebuilt powerplane world. Dual redundant BMS boards to make you feel good. Here's a greatpicture of one: http://www.avidfoxflyers.com/index.p...ttery-warning/ If you poke around, there's a nice video from the Director of Engineering at EarthX, he talks about the requirement to have a gas-tight battery box vented to the outside, to use only a three-phase alternator to charge it, and to add a crowbar circuit to prevent over-voltage. Wonder how many glider pilots go to all this trouble? I think I'll stick to SLA, just press the button and the engine starts in about a second. -Dave P.S. That StewartB in the original thread was a real hoot. Said he worried more about getting mad cow disease than having trouble with his EarthX battery. Until his battery went bad. Don't know if he still eats hamburgers or not. Dave, Perhaps you could post a link to this video - I could not find it. To the contrary, the video I could find extolled the safety of their batteries in aircraft: https://earthxbatteries.com/product-...ental-aircraft That video was in an EAA seminar: http://go.eaa.org/UVqR00U0BE0SOs03oK000hV Some good info on charging systems he https://earthxbatteries.com/engine-c...hium-batteries I'm not convinced that earthx page offers "good info". There are many obviously false statements. E.g., oxidation actually uses up oxygen, rather than create free oxygen. And generator coils do not always put out the same amount of power at a given RPM - disconnect the output and the power will be zero. Most importantly for our discussion here, their claims about what causes overheating of the battery during charging are not convincing, and I'd look for evidence elsewhere. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
PDA Battery | [email protected] | Soaring | 4 | December 28th 13 10:02 AM |
USA / The Soaring Safety Foundation (SSF) Safety Seminars 2008 | [email protected] | Soaring | 0 | November 8th 07 11:15 PM |
Find a Safety Pilot in your area with Safety Pilot Club | Safety Pilot Club | Instrument Flight Rules | 0 | December 29th 06 03:51 AM |
The Soaring Safety Foundation (SSF) Safety Seminars Hit The Road in the USA | [email protected] | Soaring | 0 | September 11th 06 03:48 AM |