Battery for gliders

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

I have also had low/bad performance from my Panasonics ... as did my
partner ... this is too much of a coincidence ... I like powersonic
.... yuasa seems fine also ... www.ragebattery.com has great prices ...
even when you include shipping.

KK


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

I have also had low/bad performance from my Panasonics ... as did my
partner .

I think much of that has to do with the charger you use. The best one I've
found is configured by the factory to the specific charging requirements of
your battery model. Check out:

http://www.xenotronix.com/products/leadacid/hpx-10.htm




Jim Vincent
N483SZ
illspam

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.

However, this retailer did mention that he had seen problems caused by
incorrect storage. High temperature and long term storage without
charging can apparently cause permanent loss of capacity. His
professional opinion was that this was more likely to be the problem
with "bad cells", especially if several were purchased from the same
place.

In any event, I've had very good luck with Powersonic cells. Their
claimed discharge curves are available on the Web, so you can see if
they meet your needs.

P3

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???

Powersonic has a 8 ah battery that is the same size as a 7 ah.


--
keithw
------------------------------------------------------------------------
Posted via OziPilots Online [ http://www.OziPilotsOnline.com.au ]
- A website for Australian Pilots regardless of when, why, or what they fly -

EaglePicher has a 9A same sixe as a 7A, cost me about $20.

Bob Fidler
"keithw" wrote in message
...

Powersonic has a 8 ah battery that is the same size as a 7 ah.


--
keithw
------------------------------------------------------------------------
Posted via OziPilots Online [ http://www.OziPilotsOnline.com.au ]
- A website for Australian Pilots regardless of when, why, or what they
fly -

Bob Fidler wrote:

EaglePicher has a 9A same sixe as a 7A, cost me about $20.

Can you give the model number and where you bought it? The only Eagle
Picher I can find that is the same size as the usual 7 AH is also 7.2 AH.

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

Eric Greenwell
Washington State
USA

Nobody has mentioned the obvious. Not everybody is using the same discharge
time.
Some are 10 hr, some are 20 hr rates. It makes a difference. Easily enough
to
change the ads. Longer times (lower discharge rates) make their advertising
look better.

The other technique is to change the discharged voltage, or the charged
voltage.

If you want a better comparison, find the curves and compare them. And the
weights.
And the size. You might be surprised to find that there is little difference
in the
capacities. Chemistry is chemistry.

The other item is to pick a bingo voltage that is correct for the
application, not the
battery. Compare the curves down to that point. If the radio or other
electronics start
to go south at 11 volts, while loaded, the curve below 11 volts will not
take care of
everything that you want to do.

Hence twice the batteries so that the amp-hours are way up there, cause you
can
only use a part of them.

Dennis

Eric Greenwell wrote in message ...
Bob Fidler wrote:

EaglePicher has a 9A same sixe as a 7A, cost me about $20.

Can you give the model number and where you bought it? The only Eagle
Picher I can find that is the same size as the usual 7 AH is also 7.2 AH.

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

Eric Greenwell
Washington State
USA

" wrote in message
...
snip
If you want a better comparison, find the curves and compare them. And the
weights.
And the size. You might be surprised to find that there is little
difference
in the
capacities. Chemistry is chemistry.

Chemistry determines the voltage, but the capacity is set by geometry and
design details. I know that Eagle-Picher has been working on inovative
woven mat designs to increase the capactiy of SLA batteries; perhaps the
unusually high capacity battery (for its size) cited earlier in this thread
uses this technology.

snip