Lithium technology batteries

Although the technology is still pricy vs lead-acid batteries, the
power/weight/size vs cost equation is getting better. Anybody using
lithium model airplane packs bundeled to produce 12 - 14 v @3 - 6 amps
as a power source for their glider? (I have been looking at the
duralite site ... I'm sure there are others.)
http://www.duralitebatteries.com/batteries.html

KiloKilo

"Ken Kochanski (KK)" wrote in message
oups.com...
Although the technology is still pricy vs lead-acid batteries, the
power/weight/size vs cost equation is getting better. Anybody using
lithium model airplane packs bundeled to produce 12 - 14 v @3 - 6 amps
as a power source for their glider? (I have been looking at the
duralite site ... I'm sure there are others.)
http://www.duralitebatteries.com/batteries.html

KiloKilo


I've been watching this too. (The model airplane guys always seem to grab
the latest technology and run with it.) The early Li-Po batteries had some
problems with catching fire when charging but it's clear that the technology
has come a long way in the last year.

There are 14V Mil-Spec Li-Po packs that would be safer to use but the prices
are still astronomical. There are also some 14.8V laptop computer battery
packs that look interesting.

One thing that worries me is that a freshly charged Li-Po "14.8V" pack will
produce a no-load voltage over 16V. A lot of avionics specify that the
maximum voltage is 16V.

Bill Daniels

voltage regulator
williscomb

"WilLiscomb" wrote in message
...
voltage regulator

...or just a forward-biased diode or three.

Vaughn

"WilLiscomb" wrote in message
...
voltage regulator
williscomb



Hmmmm

Build a 'better' battery so that you can dump power into a voltage
regulator. Cute.

Actually the forward biased semiconductor junction in the form of a diode is
a much easier way to do things.

Ian

"tango4" wrote in message
...

"WilLiscomb" wrote in message
...
voltage regulator
williscomb



Hmmmm

Build a 'better' battery so that you can dump power into a voltage
regulator. Cute.

Actually the forward biased semiconductor junction in the form of a diode
is
a much easier way to do things.

Ian



You could use a step-up switching regulator. This would, of course, have
the minor drawback of eliminating the annual "6 or 7 cell" argument on RAS.

Tim Ward

On Sun, 19 Dec 2004 19:09:49 +0000 (UTC), tango4 wrote:

"WilLiscomb" wrote in message
...
voltage regulator
williscomb



Hmmmm

Build a 'better' battery so that you can dump power into a voltage
regulator. Cute.

Actually the forward biased semiconductor junction in the form of a diode is
a much easier way to do things.

Ian

Only problem is that the voltage drop is also present at the
end-of-charge point, thus losing the last 0.7v of possible battery
voltage before things start working strangely.
If you use a well designed switching regulator which can boost as well
as buck, the voltage supplied to the instruments can be maintained in
the ideal range until the battery is almost completely flat, and at an
average efficiency of about 80%. AFAIK, complete discharge is not
harmful to NiCd, Lithium types etc. It is harmful to lead acid
batteries.
Cheers, John G.

John Giddy writes:

If you use a well designed switching regulator which can boost as well
as buck, the voltage supplied to the instruments can be maintained in
the ideal range until the battery is almost completely flat, and at an
average efficiency of about 80%.

With carefull design and construction, you can get over 95% efficient
converters running from a 12v source.

AFAIK, complete discharge is not harmful to NiCd, Lithium types
etc. It is harmful to lead acid batteries.

Full dischare of a NiCd *battery* is bad news, it is OK to fully
discharge a single cell on its own though. Lead acids can be run
totally flat, but must be put on charge imediatly or they
`sulphate'. Don't know about the various Li batteries.

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
EPIC, The Architecture of the future, always has been, always will be.

Ken Kochanski (KK) wrote:

Although the technology is still pricy vs lead-acid batteries, the
power/weight/size vs cost equation is getting better. Anybody using
lithium model airplane packs bundeled to produce 12 - 14 v @3 - 6 amps
as a power source for their glider? (I have been looking at the
duralite site ... I'm sure there are others.)
http://www.duralitebatteries.com/batteries.html


Given the cost and careful charging requirements, I'm guessing the
interest in these is to allow more amphours to be stuffed into the
glider's original battery box? Eliminating the need for adding another
box when you added a transponder/Ipaq/etc would maybe make the Li
battery cost worthwhile. For example, from the Duralite site:

The recommended
safe charging procedure for all Li-ion & Li-Poly
batteries is to charge them out of the aircraft in a �re
proof area or container. Always be present during the
charging cycle. Unplug the batteries from charger when
charging cycle is complete.


Yikes!

I don't see any other advantages for gliders over the standard sealed
lead/acid batteries, which are cheap and trouble free.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

"Eric Greenwell" wrote in message
...
Ken Kochanski (KK) wrote:

Although the technology is still pricy vs lead-acid batteries, the
power/weight/size vs cost equation is getting better. Anybody using
lithium model airplane packs bundeled to produce 12 - 14 v @3 - 6 amps
as a power source for their glider? (I have been looking at the
duralite site ... I'm sure there are others.)
http://www.duralitebatteries.com/batteries.html


Given the cost and careful charging requirements, I'm guessing the
interest in these is to allow more amphours to be stuffed into the
glider's original battery box? Eliminating the need for adding another
box when you added a transponder/Ipaq/etc would maybe make the Li
battery cost worthwhile. For example, from the Duralite site:

The recommended
safe charging procedure for all Li-ion & Li-Poly
batteries is to charge them out of the aircraft in a ?re
proof area or container. Always be present during the
charging cycle. Unplug the batteries from charger when
charging cycle is complete.


Yikes!

I don't see any other advantages for gliders over the standard sealed
lead/acid batteries, which are cheap and trouble free.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Well, Li chemistry batteries have much better performance when it's cold
than either lead, NiCd or NiMH. So that might be a consideration for those
flying wave a lot.

Tim Ward