glider battery duration problems

Can someone recommend the best LifePo battery which fits in a completely standard bracket? (In my case for an Arcus M - I have 4 Strobl panels which are supposed to generate 2.4 Ah, but I have the max amount of electronics fitted - I have not run out of power yet with 2 ordinary 7Ah gel cells, but think I might run out if a flight lasted for more than 8 hours).

Thanks for any advice, Mark Burton, 4M, London Gliding Club, UK

Soartech wrote, On 10/4/2013 10:29 AM:

I took a look at the Strobl setup and it looks great, but the price
of

$2078.40 kinda put me off.

That price is way out of line with today's solar equipment. Someone
is making a lot of profit at that level. Search around. Look at
Amazon, solarblvd.com and eBay. This is not rocket science.

I'm pretty much required to mount any solar panels on my engine doors,
which limits the area available. Strobl panels are very efficient, so
you get a lot of amps in a small size, and they flexible. That's what
you are paying for. If you know of panels comparable to the Strobls in
output for a lot less, I'd really like to know about them! I really,
really would! I have looked for such panels in the past, with no success.

Two Strobl modules for my glider, with switches, cables, adhesive,
connectors, etc, produce a nominal 860 ma., and use 1.5 sqft. The "kit"
costs 1040 Eur ($1400 US$). The panels you suggested would occupy 4.0
sqft, way too big for the engine doors, it wouldn't have all the stuff
needed for installation in a specific glider, and it wouldn't be
approved by the glider manufacturer. It may not be rocket science, but
there are good reasons that the Strobls are what you see on most gliders.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Soartech wrote, On 10/4/2013 10:17 AM:
Regarding the solar cells. Dan and Eric, I am suggesting to use your
current lead acid battery(s) and charge them with solar. The idea is
that they charge during the time the glider is on the ground before
and after flight and supplement while in flight. During flight the
200 mA.of one cell may not cover all of your current draw, most
likely. It might for me as I just have a vario, radio and Streak
connected. My experience is that the battery charges enough to keep
it going all summer. Try two cells to start with and I think you will
be surprised how well it works. It's way better than removing the
battery after every flight, taking it home and charging it which is
what my friend does. I also have a 15 Watt panel on my trailer that
runs a 4 inch 12V computer fan I installed behind the vent grill but
I can switch it over to charge the battery if I need to via a wire
pair. So far I have not needed to use it for charging. Trailer stays
cool all summer.

For your low current drain situation, 200 ma is worthwhile;
unfortunately, with a ClearNav, radio, 302, Mode C transponder,
PowerFlarm, my panel draws 2 amps until the transponder encoder is warm,
then it still draws 1.6 amps. A six hour flight uses over 9 AH.

If I had two panels with a total of 400 ma, they'd average less than 200
ma during a flight (much less if there are plenty of clouds), or only
1.2 AH added during the flight. That's insignificant, compared to the 9
AH usage.

Charging while it's tied down is problematic, too: The sun angle will
not be optimum (especially after flying), and it might be cloudy in the
morning. I need a 40 watt panel, optimally placed on the ground, to
ensure the glider is charged fully by launch time the next day. Usually,
instead of a solar panel, I use a DC/DC charger and an 18 AH battery to
do the charging overnight when I'm tied down.

It's the high drains a modern panel can consume that get people looking
at high capacity batteries and Strobl panels. Many pilots could do well
with your suggestions, however.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Thanks for the info.

Like Eric, I have high drain with the Mode S transponder (Trig TT22),
Microair 760 radio, CAI-302, Zaon MRX, and Dell Streak, all drawing on my
batteries. I estimate about 1.6-2.0 Amp hours drain.

Fortunately, for me, my glider is kept assembled in a hangar with chargers
connected full time. On the road, I have an inverter to charge up the
batteries if needed. Still, after 4 hours or so of flight, my batteries are
getting low. I need to replace them and I'm looking for something better
than SLA.

"Soartech" wrote in message
...
Regarding the solar cells.
Dan and Eric, I am suggesting to use your current lead acid battery(s) and
charge them with solar. The idea is that they charge during the time the
glider is on the ground before and after flight and supplement while in
flight. During flight the 200 mA.of one cell may not cover all of your
current draw, most likely. It might for me as I just have a vario, radio and
Streak connected. My experience is that the battery charges enough to keep
it going all summer. Try two cells to start with and I think you will be
surprised how well it works. It's way better than removing the battery after
every flight, taking it home and charging it which is what my friend does.
I also have a 15 Watt panel on my trailer that runs a 4 inch 12V computer
fan I installed behind the vent grill but I can switch it over to charge the
battery if I need to via a wire pair. So far I have not needed to use it for
charging. Trailer stays cool all summer.

Mark,

In North America, I would recommend the K2, but shipping to Europe is going to be an issue for you as may be duties. For me to import the Batteries to Canada from the US, it costs almost 50% more because of this. So you should look for a European manufacturer.

Or if you go to the US or have a friend the goes to the US take a look at the K2, or the Bioenno as suggested above and carry them home.

On 4/10/2013 10:00, Dave Springford wrote:
I think if you look at this page:
http://www.bioennopower.com/pages/12...ifepo4-battery

You will see that the pack in the picture is covered in shrink wrap,
not in a solid ABS-case. Take a look at the bulge on the right side
of the pack and the fold at the top right corner.


Yes. If you click "1. 12V Series" on the right hand menu you can see
that ABS cases are available as alternatives. The shrink wrap appears
to cover a PVC case.

GC

Am 04.10.2013 19:36, waremark wrote:
Can someone recommend the best LifePo battery which fits in a completely standard bracket? (In my case for an Arcus M - I have 4 Strobl panels which are supposed to generate 2.4 Ah, but I have the max amount of electronics fitted - I have not run out of power yet with 2 ordinary 7Ah gel cells, but think I might run out if a flight lasted for more than 8 hours).

Thanks for any advice, Mark Burton, 4M, London Gliding Club, UK

Mark,

I'd recommend this 10Ah LiFePO4 product which sells for 149.00 EUR:

http://shop.segelflugbedarf24.de/pro...-12V-10Ah.html

They also ship to UK for reasonable fares. The dimensions are the usual
151 x 65 x 94 mm and the unit contains a BMS protection and balancing
circuit. It can be charged with the usual Lead-Acid battery chargers
with no problem.

--
Peter Scholz
ASW24 JE

This looks very interesting to me:
http://www.bioennopower.com/collecti...ifepo4-battery

On the surface it appears that I may be able to wire two of them in parallel
(or series-parallel if individual cells) and enclose them in the battery
case that fits in the tail of my LAK. I'll measure it today and see if
there's a chance.



"Peter Scholz" wrote in message
...
Am 04.10.2013 19:36, waremark wrote:
Can someone recommend the best LifePo battery which fits in a completely
standard bracket? (In my case for an Arcus M - I have 4 Strobl panels
which are supposed to generate 2.4 Ah, but I have the max amount of
electronics fitted - I have not run out of power yet with 2 ordinary 7Ah
gel cells, but think I might run out if a flight lasted for more than 8
hours).

Thanks for any advice, Mark Burton, 4M, London Gliding Club, UK

Mark,

I'd recommend this 10Ah LiFePO4 product which sells for 149.00 EUR:

http://shop.segelflugbedarf24.de/pro...-12V-10Ah.html

They also ship to UK for reasonable fares. The dimensions are the usual
151 x 65 x 94 mm and the unit contains a BMS protection and balancing
circuit. It can be charged with the usual Lead-Acid battery chargers with
no problem.

--
Peter Scholz
ASW24 JE

Dan, not wishing to teach granny to suck eggs, but if you go for
Lipo in the tail (or anywhere), make sure you have a proper
battery management system in addition to a charger – apparently
the significant number of fires in Lipos in model aircraft were due to
inadequate or absent BMS. Otherss here will have more first-hand
knowledge.

(The Lak FES comes with a proper BMS for this very reason.)


Chris N

Dan Marotta wrote, On 10/5/2013 8:22 AM:
This looks very interesting to me:
http://www.bioennopower.com/collecti...ifepo4-battery


On the surface it appears that I may be able to wire two of them in
parallel (or series-parallel if individual cells) and enclose them in
the battery case that fits in the tail of my LAK. I'll measure it today
and see if there's a chance.

Be certain to read the user manual for this battery, which specifically
states series or parallel operation is not recommended! The manual also
states

"Only use 14.6V, LiFePO4 compatible chargers to charge the battery. The
charging current should be between 2A to 5A. If you need a charger,
please contact us"

Don't rely on claims for other Li batteries, like "any lead acid charger
can be used", but only go by the requirements of the manufacturer of the
battery you have.

Lithium based batteries must be taken more seriously than SLA
batteries, which are nearly identical from one manufacturer to another.
Lithium batteries, even LiFePO4, can vary substantially in their
characteristics, particularly with the type of BMS (battery management
system) installed in it, and may not even have one. Even the proper
storage varies considerably between Li and lead batteries.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)