LiPo Batteries in Gliders

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

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

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

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.

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

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.

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