Battery 6ah vs. more

wrote:
On Apr 24, 9:58 am, nimbusgb wrote:

I am flying OPA's at the moment ( other peoples aeroplanes ) and have
a portable setup with Colibri logger and Ipaq PDA all driven from a
LiPo Electric R/C aircraft flight pack. A12v pack with 2200ma/hr
capacity. The power to volume/weight ratio is great. The pack weighs
about 100g and is about the size of 6 cigarettes! It drives the setup
for about 6 hours with the pda on all the time.

Ian

I would never fly with LiPo on board. Let alone in someone elses ship.
I have quite a few of them for my R/C aircraft and have seen them at
their worst. Please be careful.

You don't fly with a cell phone or a PDA?

Marc

On Apr 24, 12:30*pm, Marc Ramsey wrote:
wrote:
On Apr 24, 9:58 am, nimbusgb wrote:

I am flying OPA's at the moment ( other peoples aeroplanes ) and have
a portable setup with Colibri logger and Ipaq PDA all driven from a
LiPo Electric R/C aircraft flight pack. A12v pack with 2200ma/hr
capacity. The power to volume/weight ratio is great. The pack weighs
about 100g and is about the size of 6 cigarettes! It drives the setup
for about 6 hours with the pda on all the time.

Ian

I would never fly with LiPo on board. Let alone in someone elses ship.
I have quite a few of them for my R/C aircraft and have seen them at
their worst. Please be careful.

You don't fly with a cell phone or a PDA?

Marc

Not with lithium Polymer batteries. Lithium Ion, yes. Lithium
Polymer, no.

wrote:
On Apr 24, 12:30 pm, Marc Ramsey wrote:
wrote:
On Apr 24, 9:58 am, nimbusgb wrote:
I am flying OPA's at the moment ( other peoples aeroplanes ) and have
a portable setup with Colibri logger and Ipaq PDA all driven from a
LiPo Electric R/C aircraft flight pack. A12v pack with 2200ma/hr
capacity. The power to volume/weight ratio is great. The pack weighs
about 100g and is about the size of 6 cigarettes! It drives the setup
for about 6 hours with the pda on all the time.
Ian
I would never fly with LiPo on board. Let alone in someone elses ship.
I have quite a few of them for my R/C aircraft and have seen them at
their worst. Please be careful.
You don't fly with a cell phone or a PDA?

Marc

Not with lithium Polymer batteries. Lithium Ion, yes. Lithium
Polymer, no.


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...

Marc

On Apr 24, 1:17*pm, Marc Ramsey wrote:
wrote:
On Apr 24, 12:30 pm, Marc Ramsey wrote:
wrote:
On Apr 24, 9:58 am, nimbusgb wrote:
I am flying OPA's at the moment ( other peoples aeroplanes ) and have
a portable setup with Colibri logger and Ipaq PDA all driven from a
LiPo Electric R/C aircraft flight pack. A12v pack with 2200ma/hr
capacity. The power to volume/weight ratio is great. The pack weighs
about 100g and is about the size of 6 cigarettes! It drives the setup
for about 6 hours with the pda on all the time.
Ian
I would never fly with LiPo on board. Let alone in someone elses ship.
I have quite a few of them for my R/C aircraft and have seen them at
their worst. Please be careful.
You don't fly with a cell phone or a PDA?

Marc

Not with lithium Polymer batteries. Lithium Ion, yes. *Lithium
Polymer, no.

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...

Marc- Hide quoted text -

- Show quoted text -

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.

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

"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

On Apr 24, 12:30*pm, Marc Ramsey wrote:
wrote:
On Apr 24, 9:58 am, nimbusgb wrote:

I am flying OPA's at the moment ( other peoples aeroplanes ) and have
a portable setup with Colibri logger and Ipaq PDA all driven from a
LiPo Electric R/C aircraft flight pack. A12v pack with 2200ma/hr
capacity. The power to volume/weight ratio is great. The pack weighs
about 100g and is about the size of 6 cigarettes! It drives the setup
for about 6 hours with the pda on all the time.

Ian

I would never fly with LiPo on board. Let alone in someone elses ship.
I have quite a few of them for my R/C aircraft and have seen them at
their worst. Please be careful.

You don't fly with a cell phone or a PDA?

Marc

Have you ever seen an R/C LiPo cell? No hard case. It is essentially
a tin-foil-like bag of chemicals with a very high energy density.