Battery safety (againish)

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.

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.

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.

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.

On Saturday, March 16, 2019 at 7:35:22 PM UTC-4, 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.

They are not adding a housing they are internally fixing it with PU resin because they had internal short circuit.

Some, maybe all LiFePO4 batteries are made up of individual cells wired
together in series to make up the full voltage.Â* If that setup is simply
stuffed into a plastic case and not secured, things can rattle around,
possibly allowing uninsulated interconnecting wires to short together.Â*
I might try stuffing foam into the battery case rather than filling it
with resin.Â* A fuse on the output cable should be considered mandatory.

On 3/16/2019 6:34 PM, Andrzej Kobus wrote:
On Saturday, March 16, 2019 at 7:35:22 PM UTC-4, 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.
They are not adding a housing they are internally fixing it with PU resin because they had internal short circuit.

--
Dan, 5J

On Saturday, March 16, 2019 at 8:34:16 PM UTC-4, Andrzej Kobus wrote:
On Saturday, March 16, 2019 at 7:35:22 PM UTC-4, 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.

They are not adding a housing they are internally fixing it with PU resin because they had internal short circuit.

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.

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...?

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).

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