Battery for gliders

"tango4" wrote in message
...
Colibri Loggers and LX vario avionics get very unpredictable over 16 volts
( in spite of what the original manuals said - up to 24v iirc ) I had a
Colibri reading over 75000 feet amsl whilst on the runway.

Ian

My Colibri manual, dated Feb. 2001, gives the operating voltage as 10-15
volts.

Papa3 wrote:
Udo,

I don't know anything about process and quality controls in battery
manufacturing, so I can't make an authoritative comment. But, I've
seen a similar complaint levelled against another supposedly
high-quality brand. In that case, annecdotal evidence from people I
trust (ie. several methodical and careful glider pilots) kept me away
from that brand. I then spoke with the guy at the local electronics
supply house, and he said he had "never, ever had a single problem"
with that brand, and he claimed to sell "hundreds of them per month."
Go figure.


Perhaps the people buying hundreds of these per month aren't trying
to run 14 volt instruments on 12 volt batteries, like so many glider
pilots do???

Hi Udo

As far as I know there is (theoretical) 2.6 V per cell in these batteries.
Though (practical) 6 cells a 2.45V gives 14.7 V.
Which charging utility do you own? Constant current or constant voltage?
These sort of batterie NEED ca constant voltage to charge of 14.7V. The
loading current is decreasing with the charging time.
Mabe you should invest in a better charging utility.
The batterie lifetime is also dependent to the current your are taking out
of it. Some are better with high current and lasting longer. Today we need
quite a lot of current for radio,GPS,Logger,PDA et. al.
There was a good paper about that in the German Aerokurier.

Check that you can charge them up to 13.6 V or more and then compare them
again with the same voltage after charge.
We had very good experience with Sonnenschein. The say to charge them with
2.4V to 2.45V per cell and 2.3V - 2.35 per cell if you charge it the whole
week until next flight. Check these things at Panasonic.

One thing I don't understand is that we own plane for 100'000$ but we want
to buy cheap batterie?

Cheers FW.

"Udo Rumpf" wrote in message
. ..
I bought two Panasonic 7,2a/h batteries and I am very disappointed.
Lucky for me I had two Yuasa 7.0 a/h units, one of which was still in
good
working order. I was able to get a direct comparison between the two.
Both Panasonic batteries show at least a 25% less performance compared to
Yuasa. This is the usable time everything being equal.

Also after "identical charge" of all three batteries the two Panasonic's
always
show the same 12.52 volt with the surface charge removed.
While the Yuasa always shows 12.76 volts.

Was I mislead by the Panasonic spec sheet?
How come the old Yuasa outperforms the two new Panasonic,
despite the fact the Panasonic is rated higher by .2 a/h ?
How am I to select the battery if I can not trust the spec sheet?
Is it all reputation. Please advise

Regards
Udo

On their way. Is the ellipses in your email address intended?