LiPo Batteries in Gliders

[GM]

Hi,

it's still winter with lousy weather in the northern hemisphere, so it
is time to warm up an old discussion. I searched the forum for threads
reg. Lithium-Polymer Batteries and there have been none for a while.
Here are the questions:
- Does anyone have real life experience with LiPo's in a glider? (real
gliders, that is - not models)
- Can I combine two 7.4V packs in series to get a 14.8V unit or is
there a risk with that?
- How would one charge a combo like this? Each unit by itself and then
hook them together or with one charger while hooked together?

The prices have dropped to a very affordable level; so have the
chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
each (0.6kg or 1.32 lbs in total)

Any input is welcome.

Uli Neumann
'GM'

[Pat Russette]

GM wrote:
> Hi,
>
> it's still winter with lousy weather in the northern hemisphere, so it
> is time to warm up an old discussion. I searched the forum for threads
> reg. Lithium-Polymer Batteries and there have been none for a while.
> Here are the questions:
> - Does anyone have real life experience with LiPo's in a glider? (real
> gliders, that is - not models)
> - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> there a risk with that?
> - How would one charge a combo like this? Each unit by itself and then
> hook them together or with one charger while hooked together?
>
> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)
>
> Any input is welcome.
>
> Uli Neumann
> 'GM'
>
>

Hello Uli,

Glider applications are a fairly deep cycle requirement (more than 30%
down from fully charged). Lipo batteries are excellent but have some
serious problems in our deep cycle application.

Lipo batteries are 3.7v when fully charged. To get higher voltages you
just put more cells in series (7.4v, 11.1v, 14.8v, etc). They discharge
at a very flat output voltage until they suddenly drop in voltage. The
problem is that if you discharge a lipo beyond the safe threshold (3v
per cell) you destroy the battery. If over discharged the battery will
overheat during recharge and burst. The material inside the batteries
plastic wrap ignites upon contact with oxygen and sticks to everything
like napalm. You will burn your house down.

Also, in an accident if the battery case if punctured then the battery
will burn.

The cell phones and model builders use electronics that turn off the
units when the voltage takes that critical drop in order to save the
battery. Someone would have to build a similar unit for sailplane use
before they could be safely used (and more importantly re-used).

I own many, many lipo batteries and sealed lead acid is what I use in my
glider.

Cheers,
Pat Russette
ASW20B-Hobbs CQ

[Eric Greenwell]

GM wrote:
> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)
Why do you wish to save 1.75 kg/3.85 pounds? That small amount can not
possibly affect your glider's performance. I mean, my drinking water
weighs about 6 pounds.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[JS]

But Pat forgot to mention Christian. Don't think he lurks here.
Christian has a 22V LiPo system with voltage regulators in his full
size AS-W27. Perhaps CB or Marty can get him to opine.
For ~10x the cost of SLA, you can have over- and under- voltage
protected LiPo batteries!
Here's an example of warnings a battery retailer gives for using
Lithium packs:
http://www.batteryspace.com/warningsforusingbatteries.aspx
Jim

[Darryl Ramm]

On Feb 24, 9:14*pm, Eric Greenwell > wrote:
> GM wrote:
> > The prices have dropped to a very affordable level; so have the
> > chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> > standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> > days. *I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> > each (0.6kg or 1.32 lbs in total)
>
> Why do you wish to save 1.75 kg/3.85 pounds? That small amount can not
> possibly affect your glider's performance. I mean, my drinking water
> weighs about 6 pounds.
>
> --
> Eric Greenwell - Washington State, USA (netto to net to email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
>
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

I agree the weight savings are irrelevant. I suspect any real interest
from Li or LiPo will be from reduced space requirements/ease of adding
more capacity and extreme capacity for very long flights etc including
low temperature operation in Wave (some LiPo have good low temperature
performance).

Still more hassle and risk than VRLA, and a lot of work to do well.

OTOH Antares flies on Li with lots of engineering to help make it
safe. I have no problem with the Antares approach, but homemade LiPo
packs and systems worry me (and I fly models with Li and LiPo, but
VRLA for the glider).


Darryl

[Morgans[_2_]]

"GM" > wrote

> it's still winter with lousy weather in the northern hemisphere, so it
> is time to warm up an old discussion. I searched the forum for threads
> reg. Lithium-Polymer Batteries and there have been none for a while.
> Here are the questions:
> - Does anyone have real life experience with LiPo's in a glider? (real
> gliders, that is - not models)

The only way I would use LiPo's in a glider would be in a fire proof, burn
though, melt through- enclosure. Like a ceramic pot with a lid, for one
good example.

> - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> there a risk with that?

Not if they are of the same manufacture, capacity and age. If they are too
much different, one of them will be over stressed and may catch fire.

> - How would one charge a combo like this? Each unit by itself and then
> hook them together or with one charger while hooked together?

Together is fine if the above conditions stated by me exist. Most people
say that if the batteries are not discharged and charged at too high of a
rate, a balancer is not necessary, or at least not absolutely necessary.

> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)

By the time you use a ceramic pot container, any weight savings is probably
gone. Having a battery catch fire in a cockpit and generating it's own
oxygen to fuel the fire would be about the worst nightmare I could imagine.
How probable is it to have this happen? Not all that great, but that one
chance is .....shudder.....bad!
--
Jim in NC

[Michael Huber]

LiPos can burn when abused, but there are also reports where a fire
(sometimes more like an explosion) started while the batteries were not in
use. A friend of mine who is working in R&D of LiPo batteries confirmed that
this may happen in some rare cases, so I definitely would not use them in my
glider. I do use A123 LiFe cells (different chemistry than LiPo!) in my self
launcher and I am very happy with the power and capacity they offer.

Michael

[jimboffin]

On 25 Feb, 07:31, "Michael Huber" > wrote:
> LiPos can burn when abused, but there are also reports where a fire
> (sometimes more like an explosion) started while the batteries were not in
> use. A friend of mine who is working in R&D of LiPo batteries confirmed that
> this may happen in some rare cases, so I definitely would not use them in my
> glider. I do use A123 LiFe cells (different chemistry than LiPo!) in my self
> launcher and I am very happy with the power and capacity they offer.
>
> Michael

And in Europe the use of Li batteries without a manufacturers TN would
invalidate your CofA and therefore your insurance! You Yanks don't
know how lucky you are.

Lol

[Gary Evans[_2_]]

On Feb 24, 8:50*pm, GM > wrote:
> Hi,
>
> it's still winter with lousy weather in the northern hemisphere, so it
> is time to warm up an old discussion. I searched the forum for threads
> reg. Lithium-Polymer Batteries and there have been none for a while.
> Here are the questions:
> - Does anyone have real life experience with LiPo's in a glider? (real
> gliders, that is - not models)
> - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> there a risk with that?
> - How would one charge a combo like this? Each unit by itself and then
> hook them together or with one charger while hooked together?
>
> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. *I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)
>
> Any input is welcome.
>
> Uli Neumann
> 'GM'

Li-Po's are the battery of choice for model planes and cars because of
their impressive power to weight but they have a significant fire
potential. They must be handled, charged and stored with care. Look at
post #3 in this thread.

http://tinyurl.com/y85o6s5

IMO not suitable for use in sailplanes.

[joesimmers]

What about Nickle Metal Hydrate Batteries? I believe these are much
safer. Has anyone sucessfully installed these in a glider?

Joe

[Bob]

Been using NIMH for 2 years in a N3DT with Xponder. Works great!

Bob

[johngalloway[_2_]]

What about Li Ion batteries like these? Is the fire risk sinificantly
less than Li Polymer?

http://www.streckenflug.at//shop/product_info.php?products_id=608

A bit pricey, and probably not approved in Europe, but might be a
thought when a transponder has to be carried.

John Galloway

[Karl Striedieck]

While charging a LiPo model airplane battery with a top-of-the-line charger
at the proper rate it burst into flame. I had carelessly left it out of the
flame-proof charge bag and when I checked strange noises the room was filled
with acrid smoke and a Mt Vesuvius mass of sputtering pyrotchnics was
burning a hole in the work bench. Don't fly with you-do-it LiPos unless you
have an ejection seat!

Karl Striedieck


"johngalloway" > wrote in message
...
> What about Li Ion batteries like these? Is the fire risk sinificantly
> less than Li Polymer?
>
> http://www.streckenflug.at//shop/product_info.php?products_id=608
>
> A bit pricey, and probably not approved in Europe, but might be a
> thought when a transponder has to be carried.
>
> John Galloway

[Dave Nadler]

On Feb 25, 9:03*am, "Karl Striedieck" > wrote:
> While charging a LiPo model airplane battery with a top-of-the-line charger
> at the proper rate it burst into flame. I had carelessly left it out of the
> flame-proof charge bag and when I checked strange noises the room was filled
> with acrid smoke and a Mt Vesuvius mass of sputtering pyrotchnics was
> burning a hole in the work bench. Don't fly with you-do-it LiPos unless you
> have an ejection seat!
>
> Karl Striedieck
>
> "johngalloway" > wrote in message
>
> ...
>
> > What about Li Ion batteries like these? *Is the fire risk sinificantly
> > less than Li Polymer?
>
> >http://www.streckenflug.at//shop/product_info.php?products_id=608
>
> > A bit pricey, and probably not approved in Europe, *but might be a
> > thought when a transponder has to be carried.
>
> > John Galloway

Karl, model gliding is DANGEROUS !
See ya, Dave

[bildan]

On Feb 24, 8:50*pm, GM > wrote:
> Hi,
>
> it's still winter with lousy weather in the northern hemisphere, so it
> is time to warm up an old discussion. I searched the forum for threads
> reg. Lithium-Polymer Batteries and there have been none for a while.
> Here are the questions:
> - Does anyone have real life experience with LiPo's in a glider? (real
> gliders, that is - not models)
> - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> there a risk with that?
> - How would one charge a combo like this? Each unit by itself and then
> hook them together or with one charger while hooked together?
>
> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. *I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)
>
> Any input is welcome.
>
> Uli Neumann
> 'GM'

Most of the dire "explosion-fire" warning here are several years out
of date. Chemistry's like LiFePo4 have no such dangers. Most 5AH and
larger packs have internal PCB's for safety.

Check out US manufacturers like Tenergy which offers a number of
"heavy duty" Li-Po and LiFePo4 packs with internal PCB's which limit
charge and discharge voltages and currents to safe levels.

One problem not mentioned is that 4-cell Li-Po can deliver as much as
17V when fully charged which is more than some avionics allow. I
would use a DC-DC converter to deliver a tightly regulated 13.8 V to
the avionics bus. DC-DC converters allow a wider choice of battery
voltages.

[jcarlyle]

This thread reminds me of the old saying: pioneers are the ones with
the arrows in their backs. SLA batteries are cheap, and their risks
are known. Why mess around and take a chance on an in-flight fire?

-John

[Dave Nadler]

On Feb 25, 10:12*am, bildan > wrote:
> On Feb 24, 8:50*pm, GM > wrote:
>
>
>
> > Hi,
>
> > it's still winter with lousy weather in the northern hemisphere, so it
> > is time to warm up an old discussion. I searched the forum for threads
> > reg. Lithium-Polymer Batteries and there have been none for a while.
> > Here are the questions:
> > - Does anyone have real life experience with LiPo's in a glider? (real
> > gliders, that is - not models)
> > - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> > there a risk with that?
> > - How would one charge a combo like this? Each unit by itself and then
> > hook them together or with one charger while hooked together?
>
> > The prices have dropped to a very affordable level; so have the
> > chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> > standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> > days. *I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> > each (0.6kg or 1.32 lbs in total)
>
> > Any input is welcome.
>
> > Uli Neumann
> > 'GM'
>
> Most of the dire "explosion-fire" warning here are several years out
> of date. *Chemistry's like LiFePo4 have no such dangers. *Most 5AH and
> larger packs have internal PCB's for safety.
>
> Check out US manufacturers like Tenergy which offers a number of
> "heavy duty" Li-Po and LiFePo4 packs with internal PCB's which limit
> charge and discharge voltages and currents to safe levels.
>
> One problem not mentioned is that 4-cell Li-Po can deliver as much as
> 17V when fully charged which is more than some avionics allow. *I
> would use a DC-DC converter to deliver a tightly regulated 13.8 V to
> the avionics bus. *DC-DC converters allow a wider choice of battery
> voltages.

Second the max voltage warning. ILEC has already seen some fried
avionics from customers experimenting with these things...
Be careful out there (check max voltage for pack and everything
in your panel FIRST),
Best Regards, Dave "YO electric"

[Mike the Strike]

Years ago, a lab next to the one I worked in had experimental
batteries under development. All the high energy density ones utilize
very reactive elements, of which lithium is one. However, nothing
would beat the sodium-sulfur battery in its capacity to "go
Vesuvius". It was colloquially referred to as "the fire and brimstone
battery". The lab had a sulfurous smell that reminded one of the
entrance to nether regions.

I'm going to stick with lead-acid, thanks very much!

Mike

[bildan]

On Feb 25, 8:48*am, Mike the Strike > wrote:
> Years ago, a lab next to the one I worked in had experimental
> batteries under development. *All the high energy density ones utilize
> very reactive elements, of which lithium is one. *However, nothing
> would beat the sodium-sulfur battery in its capacity to "go
> Vesuvius". *It was colloquially referred to as "the fire and brimstone
> battery". *The lab had a sulfurous smell that reminded one of the
> entrance to nether regions.
>
> I'm going to stick with lead-acid, thanks very much!
>
> Mike

If you think lead-acid gel-cells are safe, try a dead short on a fully
charged one. Splattering hot gelled acid is pretty nasty stuff.

[Berry[_2_]]

In article >,
Eric Greenwell > wrote:

> GM wrote:
> > The prices have dropped to a very affordable level; so have the
> > chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> > standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> > days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> > each (0.6kg or 1.32 lbs in total)
> Why do you wish to save 1.75 kg/3.85 pounds? That small amount can not
> possibly affect your glider's performance. I mean, my drinking water
> weighs about 6 pounds.

Libelle drivers understand very well why saving weight is important.
Gliders often get heavier with age. Our venerable Libelles have
accumulated repairs, more instruments, etc. so that we are often above
the (unrealistically low) "official" weight, thus incurring a handicap
penalty in sports/club class. Not really much of a competitiveness
issue, but when one nudges the "all up" weight limit, contest officials
get all serious and make unsettling noises.

[Darryl Ramm]

On Feb 25, 7:56*am, bildan > wrote:
> On Feb 25, 8:48*am, Mike the Strike > wrote:
>
> > Years ago, a lab next to the one I worked in had experimental
> > batteries under development. *All the high energy density ones utilize
> > very reactive elements, of which lithium is one. *However, nothing
> > would beat the sodium-sulfur battery in its capacity to "go
> > Vesuvius". *It was colloquially referred to as "the fire and brimstone
> > battery". *The lab had a sulfurous smell that reminded one of the
> > entrance to nether regions.
>
> > I'm going to stick with lead-acid, thanks very much!
>
> > Mike
>
> If you think lead-acid gel-cells are safe, try a dead short on a fully
> charged one. *Splattering hot gelled acid is pretty nasty stuff.

Who exactly flies with gel-cells? There is no gelled anything inside
the VRLA (Valve Regulated Lead Acid) aka SLA (Sealed Lead Acid) or
often incorrectly called "gell cell" batteries almost universally used
in gliders. There is a surprisingly small amount of liquid
electrolyte, sulfuric acid electrolyte, basically the same as inside a
regular car battery but here used to moisten the thin fiberglass mats
between the plates.

But yes the dead short scenario is a worry and people need to be
careful. These little batteries can source hundreds of amps. Most
likely is not a destructive failure of the VRLA battery but damage
caused by the wire shorting across the battery, getting red hot,
burning molten PVC insulation, etc. burning somebody or causing a
fire. There is a misconception as well that VRLA/SLA batteries are
sealed and they will explode if the pressure inside gets too high.
They are vented with neoprene valves that will release pressure so
they won't just pressurize and eventually explode, but they still can
suffer catastrophic case failure in some situations. And they can also
cause explosions if overcharged in confined spaces from the hydrogen
leaking out the neoprene valves.

Darryl

[Grider Pirate]

On Feb 25, 7:56*am, bildan > wrote:
> On Feb 25, 8:48*am, Mike the Strike > wrote:
>
> > Years ago, a lab next to the one I worked in had experimental
> > batteries under development. *All the high energy density ones utilize
> > very reactive elements, of which lithium is one. *However, nothing
> > would beat the sodium-sulfur battery in its capacity to "go
> > Vesuvius". *It was colloquially referred to as "the fire and brimstone
> > battery". *The lab had a sulfurous smell that reminded one of the
> > entrance to nether regions.
>
> > I'm going to stick with lead-acid, thanks very much!
>
> > Mike
>
> If you think lead-acid gel-cells are safe, try a dead short on a fully
> charged one. *Splattering hot gelled acid is pretty nasty stuff.

That's why it's a good idea to use a FUSE and keep the terminals
covered. I can't think of any high capacity battery that won't react
spectacularly to a dead short.

[Jim[_18_]]

On Feb 25, 6:03*am, "Karl Striedieck" > wrote:
> While charging a LiPo model airplane battery with a top-of-the-line charger
> at the proper rate it burst into flame. I had carelessly left it out of the
> flame-proof charge bag and when I checked strange noises the room was filled
> with acrid smoke and a Mt Vesuvius mass of sputtering pyrotchnics was
> burning a hole in the work bench. Don't fly with you-do-it LiPos unless you
> have an ejection seat!
>
> Karl Striedieck
>
> "johngalloway" > wrote in message
>
> ...
>
>
>
> > What about Li Ion batteries like these? *Is the fire risk sinificantly
> > less than Li Polymer?
>
> >http://www.streckenflug.at//shop/product_info.php?products_id=608
>
> > A bit pricey, and probably not approved in Europe, *but might be a
> > thought when a transponder has to be carried.
>
> > John Galloway

Here's an intersting video of a laptop battery fire.

http://www.youtube.com/watch?v=mlZggVrF9VI

Jim

[Morgans[_2_]]

"Michael Huber" > wrote

> I do use A123 LiFe cells (different chemistry than LiPo!) in my self
> launcher and I am very happy with the power and capacity they offer.

I agree, with using A123 cells. They are coming down in price, pretty
rapidly too, I think. Shoot, even Lowe's hardware and lumber stores are
selling them!
--
Jim in NC

[joesimmers]

> I agree, with using A123 cells. *They are coming down in price, pretty
> rapidly too, I think. *Shoot, even Lowe's hardware and lumber stores are
> selling them!


Are these the same type of batteries that you find in cordless drills?

[SF]

On Feb 24, 10:50*pm, GM > wrote:
> Hi,
>
> it's still winter with lousy weather in the northern hemisphere, so it
> is time to warm up an old discussion. I searched the forum for threads
> reg. Lithium-Polymer Batteries and there have been none for a while.
> Here are the questions:
> - Does anyone have real life experience with LiPo's in a glider? (real
> gliders, that is - not models)
> - Can I combine two 7.4V packs in series to get a 14.8V unit or is
> there a risk with that?
> - How would one charge a combo like this? Each unit by itself and then
> hook them together or with one charger while hooked together?
>
> The prices have dropped to a very affordable level; so have the
> chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
> standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
> days. *I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
> each (0.6kg or 1.32 lbs in total)
>
> Any input is welcome.
>
> Uli Neumann
> 'GM'

Uli, call me. I just bought a 12V 10 Ah Lithium Phosphate battery
from K2. It comes in the same physical package as a 7 Ah 12 V SLA
battery, it much lighter than a normal SLA battery and my preliminary
tests indicates it has a useful capacity almost equal to a 12 Ah SLA
battery. It has a circuit board in it to balance the individual cell
charge while charging, and it includes over discharge protection as
well. This looks like a safe alternative to the SLA batteries and if
you factor in the increased number of cycles available, its going to
be cheaper in the long run.

SF

[Darryl Ramm]

On Feb 25, 5:21*pm, joesimmers > wrote:
> > I agree, with using A123 cells. *They are coming down in price, pretty
> > rapidly too, I think. *Shoot, even Lowe's hardware and lumber stores are
> > selling them!
>
> Are these the same type of batteries that you find in cordless drills?

The A123 cells, is a specific type of Li battery. LiFe aka Lithium
Iron Phosphate or sometimes stated as "Lithium Iron" but not to be
confused with Lithium-Ion (the standard Li chemistry). There are
several other Li chemistries in use. e.g. don't confuse the A123 LiFe
secondary battery with the LiFeS2 (Lithium Iron Disulfide) primary
battery chemistry used in ELT and PLB batteries and in the Energizer
e2 batteries for use in the SPOT messenger.

Nowadays cordless drills likely run on NiMh (Nickel metal hydride) or
standard Li-Ion or yes some do have the A123 cells.

Darryl

[Morgans[_2_]]

"Darryl Ramm" > wrote

> Geez where is your man tool lust? :-)

> DeWalt 36 Volt systems uses the A123 batteries or t least their
chemistry (DeWalt may call that nano-phosphate, same stuff, different
name). I think there are companies using that, and there have been
disputes between companies maybe breaching A123 patents/IP).

> My SureFire tactical flashlights run on CR123A Lithium.

I have plenty power tool lust, but not the wallet to match it! :-)

I am locked in, so to speak, to the B & D firestorm line of battery powered
18 volt tools. At last count, I have 11 functioning batteries, 4 drills
(one is a 1/2" hammer drill) an impact driver, two radios, 3 rapid chargers,
circular saw, reciprocating saw, two random orbital sanders, chain saw,
flashlight, dustbuster type vacuum, and probably a couple other tools that I
have forgotten to mention.

To replace them with the latest and greatest technology now available would
be overly expensive. If I need more power than 18 volts, I have plenty of
plug in tools, a 2500 watt inverter, and a 2200 watt Honda generator. Until
all of the B & D tools die, (they don't seem to die even with very tough
use, building houses and more) I'll stick with what I have, and "try" to
ignore all the new stuff. It's better that way. "sniff, sniff." ;-)
--
Jim in NC

[GM]

Wow - I hit the motherlode of info on this subject!
Berry had it right: the main reason for me looking into this
technology is to save weight. You guys in ships that can load enough
water to turn any desert into a green garden of Eden have no idea how
difficult it is to stay under a MTOW of 667#. Reducing the weight of
the battery while maintaining the capacity is a consideration and yes
- I am shedding pounds through diet and exercise, too! ;-)
Uli

[Eric Greenwell]

GM wrote:
> Wow - I hit the motherlode of info on this subject!
> Berry had it right: the main reason for me looking into this
> technology is to save weight. You guys in ships that can load enough
> water to turn any desert into a green garden of Eden have no idea how
> difficult it is to stay under a MTOW of 667#. Reducing the weight of
> the battery while maintaining the capacity is a consideration and yes
> - I am shedding pounds through diet and exercise, too! ;-)
>
The Streckenflug battery is the best choice I've seen so far in a
lithium battery for a glider, as long as your equipment can take the 16+
volts it starts out at. Many of the radios and transponders operate at
10-30 volts, so no problem there, but your logger, vario, etc may not.

At 550 euro for the battery and charger, it's almost $200/pound to save
weight that way! Great diet incentive, I suppose. Still, could be worth
it in some circumstances.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[33]

I have been flying with an Ultralife UBBL09 Li Ion battery for several
years now with very good results. This is a military grade battery
and built to very high standards. It comes integraded with 12 and
24VDC output from the same battery and also has LCD charge
indicators. Because the Li discharge curve running flat at 11.1, I
run the battery at 24VDC with a 12VDC voltage regulator to maintain
constant voltage to the radio to improve performance. The transponder
takes 24VDC, so I don't need to regulate that. Other instruments are
much less sensitive to voltage. I run a 4700, 302 and transponder and
go on multiple day 8 hour cross country flights without recharging.
The only draw back is the insane price for the battery and charging
system. I am contemplating upgrading my panel to all glass and will
add an additional UBBL09 to power all the electric instruments.

-Christian Mackin
ASW-27 #33

[Michael Huber]

From: "Dave Nadler" >

>Second the max voltage warning. ILEC has already seen some fried
>avionics from customers experimenting with these things...

This is just one more reason to use LiFe instead of LiPo or LiIo. A
fully charged A123 LiFe pack delivers 14,4V (3,6V x 4), same as SLA.
20 A123 cells in 4s/5p configuration have almost the same dimensions
as a 12V/7Ah SLA but offer slightly more voltage, 11,5Ah and power to
start a car at 70% of the SLAs weight. And you can fast charge the
pack in 15 minutes if your charger can deliver 50 amps :-)

Michael

[Darryl Ramm]

On Feb 26, 12:11*am, 33 > wrote:
> I have been flying with an Ultralife UBBL09 Li Ion battery for several
> years now with very good results. *This is a military grade battery
> and built to very high standards. *It comes integraded with 12 and
> 24VDC output from the same battery and also has LCD charge
> indicators. *Because the Li discharge curve running flat at 11.1, I
> run the battery at 24VDC with a 12VDC voltage regulator to maintain
> constant voltage to the radio to improve performance. *The transponder
> takes 24VDC, so I don't need to regulate that. *Other instruments are
> much less sensitive to voltage. I run a 4700, 302 and transponder and
> go on multiple day 8 hour cross country flights without recharging.
> The only draw back is the insane price for the battery and charging
> system. *I am contemplating upgrading my panel to all glass and will
> add an additional UBBL09 to power all the electric instruments.
>
> -Christian Mackin
> ASW-27 *#33

More of a general comment, but I am not sure there is a general need
to introduce a voltage converter, maybe with specific avionics here
there is.

Modern radios, transponders etc. have high-performance switch mode
power supplies and should work well on relatively low voltage. e.g.
Picking the Becker AR4201 as an example - the marketing data sheet
specs to a minimum voltage of 10.0V. Unfortuantly with the AR4201
example it is assuming a lead acid battery and will start blinking its
display as a low voltage warning at 10.5 volts even though I believe
it will run fine. I wish Becker would allow that warning to be
disabled/adjusted. An Ultralife UBBL09 should not drop below 10V at
typical glider avionics current draw until well over 95% discharged,
when the voltage will then decrease rather rapidly. And I suspect that
AR 4201 marketing spec is a bit conservative.

Avionics manufacturers don't always spec the minimum voltages properly
(they don't think anybody runs on batteries and/or cares) and their
products may be engineered better than the marketing data sheet specs
imply, and they often are to meet specs like RTCA DO-160F (e.g. Trig
has clarified in the past that their TT-21 transponder operates
normally down to 9 volts because of this).

Running the Ultralife UBBL09 with the packs configured in 24 Volt mode
will reduce internal resistance losses, but the external 24 V to 12 V
converter introduces conversions losses for devices powered by that.
So without more information it is not obvious what configuration
results in the longest usable battery charge. But an additional
voltage converter it is just another thing to go wrong and unless
there was a specific piece of electronics that was shown to have
problems I would avoid them. But maybe doing this to getting rid of
things like meaningless warning/blinking displays in the case of an
AR4201 is worth it. (BTW I hope Becker does something more flexible
with the new AR6201 radio).

Darryl

[bildan]

On Feb 26, 1:56*am, "Michael Huber" > wrote:
> From: "Dave Nadler" >
>
> >Second the max voltage warning. ILEC has already seen some fried
> >avionics from customers experimenting with these things...
>
> This is just one more reason to use LiFe instead of LiPo or LiIo. A
> fully charged A123 LiFe pack delivers 14,4V (3,6V x 4), same as SLA.
> 20 A123 cells in 4s/5p configuration have almost the same dimensions
> as a 12V/7Ah SLA *but offer slightly more voltage, 11,5Ah and power to
> start a car at 70% of the SLAs weight. And you can fast charge the
> pack in 15 minutes if your charger can deliver 50 amps :-)
>
> Michael

Ahh.. 14.4V is the NOMINAL voltage for a 4-cell LiFePo4. However, put
a good DVM on a 4-cell pack after a full charge and you can see
anything up to 17V. It will drop back to 14.4V pretty quick but,
'apparently', can do some avionics damage before it does. (My
Microair manual lists 16V as the maximum.) An alternative to a DC-DC
regulating converter is to just discharge a fresh pack a bit until the
slight overcharge is dissipated.

[Eric Greenwell]

33 wrote:
> I have been flying with an Ultralife UBBL09 Li Ion battery for several
> years now with very good results. This is a military grade battery
> and built to very high standards. It comes integraded with 12 and
> 24VDC output from the same battery and also has LCD charge
> indicators. Because the Li discharge curve running flat at 11.1, I
> run the battery at 24VDC with a 12VDC voltage regulator to maintain
> constant voltage to the radio to improve performance. The transponder
> takes 24VDC, so I don't need to regulate that. Other instruments are
> much less sensitive to voltage. I run a 4700, 302 and transponder and
> go on multiple day 8 hour cross country flights without recharging.
> The only draw back is the insane price for the battery and charging
> system. I am contemplating upgrading my panel to all glass and will
> add an additional UBBL09 to power all the electric instruments.
>
What is the price, and where are they available?

What was the main reason for going to this battery?

What radio do you have? Many of the new ones work up to 30 volts.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[33]

> > What is the price, and where are they available?
> > What was the main reason for going to this battery?
> > What radio do you have? Many of the new ones work up to 30 volts.

> Eric Greenwell - Washington State, USA (netto to net to email me)

www.ultralifebatteries.com

I use this battery because it allows me to have up to 36Ah at 12VDC in
the battery pockets in my ASW-27. This should allow me to run an all
glass cockpit including a Ultimate and a transponder as well as 5
other electronic gages for a very long day.

They run about $500 for the battery and $300 for the charger. It
definately does not make any financial sense to buy these. There is
NO ROI. Using the charger is highly recommended for safety reasons.

I use a Dittal FSG70 which has a warning flash at 10.5VDC as described
above. Dittal says that it can operate up to 28VDC as long as you use
the 12VDC regulator that they provide. Go figure!!! I sent for the
regulator from Dittal. I was having problems with long distance radio
transmission clarity and thought that I would give this a try. It
stops the flashing and I don't hear "Say Again" as much.

[Michael Huber]

>Ahh.. 14.4V is the NOMINAL voltage for a 4-cell LiFePo4.

No, 14.4V (3.6V x 4) is the recommended charger cut off voltage for 4s LiFe,
nominal voltage is 13.2V (3.3V x 4). If a good DVM reads 17V on a 4s LiFe
Pack you are overcharging the cells, probably using LiIo or LiPo settings on
your charger. Go to http://www.a123systems.com/a123/products , choose
"download specs" and check yourself in the data sheet.

If you are really overcharging a 4s LiFe to 17V at least you demonstrated
why it is MUCH better to use LiFe than LiPo ;-)

Michael