Battery 6ah vs. more

wrote:
Sorry, didn't mean to start an argument. Maybe my caution regarding
flying with R/C (foil bag) LiPo batteries is a little over the top. I
can live with erring on the side of caution. To each his own.

I'm not trying to get into an argument either, just making the point
that most of us already carry several foil bag lithium polymer batteries
in our gliders. The original metal case lithium ion batteries haven't
been used in consumer products for years, mostly because we want
everything light (remember 8 lb laptops?).

R/C batteries have a high (explosive 8^) failure rate mostly due to the
various kinds of abuse they are subject to, incorrect charging,
continued use after being damaged in crashes, overly high discharge
rates, full short circuits, etc. If someone knows what they are doing,
there shouldn't be a problem. But, I agree, if you don't know, don't do
it. I, for one, wouldn't want a pack large enough to power a radio and
transponder in my glider...

Marc

On Apr 24, 1:28*pm, Marc Ramsey wrote:
wrote:
Sorry, didn't mean to start an argument. Maybe my caution regarding
flying with R/C (foil bag) LiPo batteries is a little over the top. I
can live with erring on the side of caution. To each his own.

I'm not trying to get into an argument either, just making the point
that most of us already carry several foil bag lithium polymer batteries
in our gliders. *The original metal case lithium ion batteries haven't
been used in consumer products for years, mostly because we want
everything light (remember 8 lb laptops?).

R/C batteries have a high (explosive 8^) failure rate mostly due to the
various kinds of abuse they are subject to, incorrect charging,
continued use after being damaged in crashes, overly high discharge
rates, full short circuits, etc. *If someone knows what they are doing,
there shouldn't be a problem. *But, I agree, if you don't know, don't do
it. *I, for one, wouldn't want a pack large enough *to power a radio and
transponder in my glider...

Marc

I have done the RC thing for over 45 years. I've observed that as the
use of LiPo cells have progressed the rate of failure has decreased.
Inspite of that I would also either use a metal cased cells or a pack
in a metal box if I were to use them in an aviation application.
Istalled in the PDA or Cell phone they have some puncture protection
and that seems to be one of the major hazards to their use.

On the same idea; the A123systems cells are metal cased and at $110
for six (2.3 Ah) of them is a pretty good deal as far as lithium cells
go. I'm planning on getting several "Developer Kits" to assemble
several packs for the glider. Four cells, each a little larger than a
AA Alkaline, means that I can get a pretty good serial/parallel
battery setup and fit the individual battery packs into small
spaces.

The BIG handicap is the cost; to assemble 3 packs will cost $220 plus
assembly and wiring, for a 7.2AH pack.

"SoaringXCellence" wrote in message
...
On Apr 24, 1:28 pm, Marc Ramsey wrote:
wrote:
Sorry, didn't mean to start an argument. Maybe my caution regarding
flying with R/C (foil bag) LiPo batteries is a little over the top. I
can live with erring on the side of caution. To each his own.

I'm not trying to get into an argument either, just making the point
that most of us already carry several foil bag lithium polymer batteries
in our gliders. The original metal case lithium ion batteries haven't
been used in consumer products for years, mostly because we want
everything light (remember 8 lb laptops?).

R/C batteries have a high (explosive 8^) failure rate mostly due to the
various kinds of abuse they are subject to, incorrect charging,
continued use after being damaged in crashes, overly high discharge
rates, full short circuits, etc. If someone knows what they are doing,
there shouldn't be a problem. But, I agree, if you don't know, don't do
it. I, for one, wouldn't want a pack large enough to power a radio and
transponder in my glider...

Marc

I have done the RC thing for over 45 years. I've observed that as the
use of LiPo cells have progressed the rate of failure has decreased.
Inspite of that I would also either use a metal cased cells or a pack
in a metal box if I were to use them in an aviation application.
Istalled in the PDA or Cell phone they have some puncture protection
and that seems to be one of the major hazards to their use.

On the same idea; the A123systems cells are metal cased and at $110
for six (2.3 Ah) of them is a pretty good deal as far as lithium cells
go. I'm planning on getting several "Developer Kits" to assemble
several packs for the glider. Four cells, each a little larger than a
AA Alkaline, means that I can get a pretty good serial/parallel
battery setup and fit the individual battery packs into small
spaces.

The BIG handicap is the cost; to assemble 3 packs will cost $220 plus
assembly and wiring, for a 7.2AH pack.

It would be cheaper to buy a pair of DeWalt 36V LiFePo4 power tool batteries
from eBay for around $150. Each pack contains 10 A123 Systems 3.6V 2.3AH
cells. A 4x5 pack would be a nice 14.4V, 11.5AH glider battery.

Bill D

On Apr 24, 5:52 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"SoaringXCellence" wrote in message

...
On Apr 24, 1:28 pm, Marc Ramsey wrote:



wrote:
Sorry, didn't mean to start an argument. Maybe my caution regarding
flying with R/C (foil bag) LiPo batteries is a little over the top. I
can live with erring on the side of caution. To each his own.

I'm not trying to get into an argument either, just making the point
that most of us already carry several foil bag lithium polymer batteries
in our gliders. The original metal case lithium ion batteries haven't
been used in consumer products for years, mostly because we want
everything light (remember 8 lb laptops?).

R/C batteries have a high (explosive 8^) failure rate mostly due to the
various kinds of abuse they are subject to, incorrect charging,
continued use after being damaged in crashes, overly high discharge
rates, full short circuits, etc. If someone knows what they are doing,
there shouldn't be a problem. But, I agree, if you don't know, don't do
it. I, for one, wouldn't want a pack large enough to power a radio and
transponder in my glider...

Marc

I have done the RC thing for over 45 years. I've observed that as the
use of LiPo cells have progressed the rate of failure has decreased.
Inspite of that I would also either use a metal cased cells or a pack
in a metal box if I were to use them in an aviation application.
Istalled in the PDA or Cell phone they have some puncture protection
and that seems to be one of the major hazards to their use.

On the same idea; the A123systems cells are metal cased and at $110
for six (2.3 Ah) of them is a pretty good deal as far as lithium cells
go. I'm planning on getting several "Developer Kits" to assemble
several packs for the glider. Four cells, each a little larger than a
AA Alkaline, means that I can get a pretty good serial/parallel
battery setup and fit the individual battery packs into small
spaces.

The BIG handicap is the cost; to assemble 3 packs will cost $220 plus
assembly and wiring, for a 7.2AH pack.

It would be cheaper to buy a pair of DeWalt 36V LiFePo4 power tool batteries
from eBay for around $150. Each pack contains 10 A123 Systems 3.6V 2.3AH
cells. A 4x5 pack would be a nice 14.4V, 11.5AH glider battery.

Bill D

Here's another source for LiFePo cells, that offer pre-fab batteries
of higher density/$ ($200/10AH as opposed to $220/7AH + assembly/
wiring) for although they claim not to be able to take on any new
customers, I bet they could be talked into coming off some:
http://www.powerstream.com/LLL.htm

Paul Hanson

I want to second Bill's comment.
A123 cells are also "much less" sensitive to charging error, as well
they can be discharged at a higher rate. They are 20% heavier
everything else being equal then the Polymer cells. They have no
memory and 1000 plus cycles. The last I heard the Dewalt pack of 10
cells can be had for about $100.00 but that was six month ago.
Udo




I have done the RC thing for over 45 years. *I've observed that as the
use of LiPo cells have progressed the rate of failure has decreased.
Inspite of that I would also either use a metal cased cells or a pack
in a metal box if I were to use them in an aviation application.
Istalled in the PDA or Cell phone they have some puncture protection
and that seems to be one of the major hazards to their use.

On the same idea; the A123systems cells are metal cased and at $110
for six (2.3 Ah) of them is a pretty good deal as far as lithium cells
go. *I'm planning on getting several "Developer Kits" to assemble
several packs for the glider. *Four cells, each a little larger than a
AA Alkaline, means that I can get a pretty good serial/parallel
battery setup and fit the individual battery packs into small
spaces.

The BIG handicap is the cost; to assemble 3 packs will cost $220 plus
assembly and wiring, for a 7.2AH pack.

It would be cheaper to buy a pair of DeWalt 36V LiFePo4 power tool batteries
from eBay for around $150. *Each pack contains 10 A123 Systems 3.6V 2.3AH
cells. *A 4x5 pack would be a nice 14.4V, 11.5AH glider battery.

Bill D- Hide quoted text -

- Show quoted text -

It would be cheaper to buy a pair of DeWalt 36V LiFePo4 power tool batteries
from eBay for around $150. Each pack contains 10 A123 Systems 3.6V 2.3AH
cells. A 4x5 pack would be a nice 14.4V, 11.5AH glider battery.

Bill D- Hide quoted text -

Here is a great resource site for info on converting DeWalt batteries:
http://www.slkelectronics.com/DeWalt/index.htm There is lots of
useful info that could potentially save someone from doing something
unintentional and unfortunate.

Paul

On 25 Apr, 03:41, Udo wrote:
I want to second Bill's comment.
A123 cells are also "much less" sensitive to charging error, as well
they can be discharged at a higher rate. They are 20% heavier
everything else being equal then the Polymer cells. They have no
memory and 1000 plus cycles. The last I heard the Dewalt pack of 10
cells can be had for about $100.00 but that was six month ago.
Udo

I have done the RC thing for over 45 years. I've observed that as the
use of LiPo cells have progressed the rate of failure has decreased.
Inspite of that I would also either use a metal cased cells or a pack
in a metal box if I were to use them in an aviation application.
Istalled in the PDA or Cell phone they have some puncture protection
and that seems to be one of the major hazards to their use.

On the same idea; the A123systems cells are metal cased and at $110
for six (2.3 Ah) of them is a pretty good deal as far as lithium cells
go. I'm planning on getting several "Developer Kits" to assemble
several packs for the glider. Four cells, each a little larger than a
AA Alkaline, means that I can get a pretty good serial/parallel
battery setup and fit the individual battery packs into small
spaces.

The BIG handicap is the cost; to assemble 3 packs will cost $220 plus
assembly and wiring, for a 7.2AH pack.

It would be cheaper to buy a pair of DeWalt 36V LiFePo4 power tool batteries
from eBay for around $150. Each pack contains 10 A123 Systems 3.6V 2.3AH
cells. A 4x5 pack would be a nice 14.4V, 11.5AH glider battery.

Bill D- Hide quoted text -

- Show quoted text -

http://www.lange-aviation.com/htm/en...ry_system.html

Antares flys on Lithium Ion batteries. I have no problem with my light
current draw, aluminium boxed, low current consumption LiPo pack that
is always within eyesight in the cockpit.

At worst I can stuff it out of the clear view panel!



Ian

"Marc Ramsey" wrote in message
t...
wrote:


What makes you think the "lithium ion" cells used in PDAs, laptops, and
cellphones are any different than the "lithium polymer" cells used in R/C
aircraft? Have you ever looked at the cells inside a PDA, or inside the
plastic cases used for cellphone or laptop batteries? Nearly all are
lithium polymer these days (and the R/C suppliers get theirs from the same
factories, which is why they are relatively cheap), although the laptop
manufacturers, thanks to some rather public incidents, are just starting
to switch over to newer, somewhat less flammable, battery chemistries...




very interesting


mk5000

"Okay, the main air ducts lead to the central system. From there I
can take any branch and drop into the lobby. It's about a 20-plus foot drop
so. I'll probably break my leg - maybe both, but that's okay. This is good.
This is a good plane. Somebody uh, give me a screwdriver. "--Mike Cannon:
Las Veas