On Sat, 26 Nov 2016 19:14:51 -0800, Casey wrote:

On Saturday, November 26, 2016 at 5:27:00 PM UTC-5, 2G wrote:
On Saturday, November 26, 2016 at 5:39:58 AM UTC-8, krasw wrote:
Why bother with solar panels when you can buy light weight lithium
batteries with enough juice for anything you can imagine? Solar
panels are from age of lead batteries.

Besides effectively increasing battery capacity, they are very useful
for recharging the batteries between flights. We are continuing to add
electronic devices (transponders, flarm, foot warmers, etc.) while
on-board battery capacity is stagnant. In some gliders, like the DG80x,
battery capacity is already at a critical level (and lithiums are not
an option). If I ordered a new glider I would definitely go with the
solar option (assuming it is available with Strobls closing).

Tom

Yes, maybe more electronics are added, but aren't electronics more
efficient now and draw less? I don't know, but what is the power
consumption of 70-80's electronics compared to today? But....

And wiring a new glider for a solar panel and especially a motorized
glider is one thing, but adding to a older glider has to be almost
impossible or at least for anyone that I could find locally or readily.
I do not believe in redoing an older glider to modern specs of adding
the flarm, and glass displays, and twin batteries, and solar panels, and
ADS-B, and ballistic chutes....bla, bla, bla......My point is there is
only so much that can be added or changed that effects weight and
balance, performance, and being cost prohibitive....Am I correct in
saying that? The old saying KISS has to come into play at some point.
Instead of figuring out how to run wiring for a solar panel, I would
settle for easy replacement of TE tubing in the boom. And I will just
keep charging my Lion battery every 2- 3 or so flights.

I have an early Libelle that I've equipped with a selection of electronic
toys for its panel:

- One battery drives 2 x electric vario (SDI C4, B40), FLARM,
PDA running LK8000. This setup uses 483 mA, with the majority used
by the PDA, thought it was probably charging its internal battery
when I made the measurement.

- Second battery runs the T&B plus a ATR-500 radio. These use 170 ma
with both running. Transmitting adds 110 mA on transmit and the T&B has
a momentary 1100 mA spike when it spins up. The radio is now a KRT2.

Both batteries are 12v 7.2Ah SLA and both are connected to an EW
Microrecorder (logger) via diodes, so the higher voltage battery drives
it. Both are mounted in the original battery box, though with a new,
raised lid to clear the bigger battery bulk and to act as a mount for the
EW Microrecorder.

The W&B is fine. Everything except the T&B is running throughout a
typical flight. In fact I power everything up except the T&B just before
towing out and then leave it all on until just before tiedown or derig.
I've never got near flattening the batteries with this approach. I've
measured the power consumption of everything except the EW logger. and
this indicates that I should get something approaching 14 hours operation
from fully charged batteries in good condition.

On top of that the B.40 has a 9v backup battery that should run it for 12
hours and the PDA (a Medion S3747) claims 6-8 hours operation off a fully
charged 800 mAh battery.

So, if you're worried about your power consumption in flight, a good one-
off winter project would be to measure the power your rig uses with all
its normal equipment running.

If you also check your batteries by measuring their capacity annually,
you'll know when to replace them and if they'll handle the longest flight
you're likely to make.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |