Today's Message Index:
----------------------
1. 06:18 AM - Re: Battery capacity tester- Why isn't there a flyback diode? (Eric M. Jones)
2. 07:33 AM - Re: Re: Battery capacity tester- Why isn't there a flyback diode? (Roger & Jean)
3. 10:00 AM - Re: Re: Battery capacity tester- Why isn't there a flyback diode? (Robert L. Nuckolls, III)
4. 10:28 AM - Heathrow 787 fire (Robert L. Nuckolls, III)
5. 10:30 AM - Re: Lithium Ferrous Batteries (Robert L. Nuckolls, III)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Battery capacity tester- Why isn't there a flyback |
diode?
There probably should be a "flyback" diode there. Actually I've been searching
the antique shops for an AC plug-in clock and haven't been able to find one.
This issue of EDN has a plethora of battery-related designs, among which is a similar
battery-tester. See attached.
http://www.edn.com/design/analog/4368112/Circuit-measures-battery-capacity?elq=e82db0a50e5244e5961468cc2f470404&elqCampaignId=258
ps: The 787 has yet ANOTHER battery problem. Yikes!
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=404929#404929
Attachments:
http://forums.matronics.com//files/battery_tester_873.pdf
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Battery capacity tester- Why isn't there a |
flyback diode?
Actually I've been searching the antique shops for an AC plug-in clock and
haven't been able to find one.
Walmart has a couple of these clocks in the $10 range.
I bought one at my local store recently.
Roger
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Battery capacity tester- Why isn't there |
a flyback diode?
At 09:32 AM 7/19/2013, you wrote:
><mrspudandcompany@verizon.net>
Yes, a coil spike suppressor would e good idea.
Should have been there in the first place . . . sorry
'bout that.
>Actually I've been searching the antique shops for an AC plug-in
>clock and haven't been able to find one.
> Walmart has a couple of these clocks in the $10 range.
> I bought one at my local store recently.
But they are getting harder to find. The AA powered
quartz movement has all but totally captured the
wall/desk clock market.
The cap-tester I photographed last week measures
both battery voltage and elapsed time in software.
Bob . . .
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Heathrow 787 fire |
>
>ps: The 787 has yet ANOTHER battery problem. Yikes!
I've been reading some of the un-journalistic babbling
about the Heathrow event. Yes, the ELT was located in
the fire zone. Yes, it contains a lithium battery. But . . .
The history of this design goes back about 8 years
with 6000+ in service. The battery is never 'charged'
hence any triggering event for battery failure is limited
to electronic failure in the ELT or external environmental
effects (temperature, vibration, etc.).
The paper, voice and byteprint pundits are not
known for their sense of history or technical acumen.
A mention of the word 'lithium' in an aviation
context has the effect of an overdose of meth.
I remain skeptical that the ELT battery is
root cause of this event but hopefully, more
level headed investigators will ultimately
prevail.
There is another feature of the 797 construction
that I find more disturbing.
Look through the collection of videos and pictures
for the SFO event. As soon as the wreckage comes
to rest people are exiting the front of the aircraft
on slides, many carrying their bags. Even videos
of trucks spraying water and/or foam are remarkably
clear of visible flames.
Aftermath pictures show little evidence of
active burning outside the fuselage eitehr right
or left side. There is no evidence of burn thru
from outside.
Yet, there are huge holes in the fuselage top
which had to be caused by release of combustion
energy inside the fuselage. Fortunately, by
the time all that stuff was fully involved,
the airplane was largely empty of passengers.
This offers questions about the combustibility
of materials in the cabin.
Check the few pictures of the Heathrow
event airplane. Once again we see evidence of
heat damage to outside of the aircraft no doubt
caused by combustion of stuff inside the airplane
with convection concentrating effects on the
roof of the cabin.
No doubt the ELT was burned. Recall that Swissair 111
suffered a cabin fire that started with arcing of
wires with damaged insulation but PROPAGATED by
combustible materials adjacent to the failed
wires.
I am reluctant to jump onto the lithium wagon
for assigning root cause to this event.
Bob . . .
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Lithium Ferrous Batteries |
At 09:48 PM 7/17/2013, you wrote:
Bob, I've been a customer of Pegasus Auto Racing for a few years now.
I started out buying silicon radiator hose from them, they sent a
catalog and I found quite a few aircraft related items and their
prices are certainly no worse than Spruce so if they have the item I
need I usually get it from them. This is by way of saying they are a
good solid business.
When I received their latest catalog I noticed that they are carrying
the Ballistic Performance EV02 line of Lithium Ferrous batteries.
https://www.pegasusautoracing.com/group.asp?GroupID=BALLISTICEVO2
What I don't get is that they spec them by number of cells. >From my
limited understanding I would expect that the 2 cell battery would
put out ~3 volts on each cell being something like an A123 size
lithium battery of ~1.5 volts.
Flying an electrically dependant engine on my trike, the little HKS
700 has CDI ignitions but they are not powered separately like the
Rotax, I have been thinking of a winter project of adding one of these:
The lithium cells deliver energy at about 3v
per cell . . .
http://tinyurl.com/la8nhr6
Hence, a 12v battery is made up of an array of 4
cells. Larger capacity batteries will add increments
of 4 cells in parallel.
https://www.pegasusautoracing.com/productdetails.asp?RecID=9402
as a reserve battery just for the ignition. I don't fly IFR or nights
and rarely more than a half hour from an airport so 8 amp hours looks
to give me at least an hour of reserve to get me to a safe touch down
with power to spare. At 15 oz. the wires to hook it up would almost
outweigh the battery. Have you ever heard of them?
I've seen this product offered by various vendors
for several years. Not heard anything 'unhappy'
about them. I note that this series of batteries
have multi-conductor service connectors on them.
This suggests that they offer a specially maintenance
tool for charging and testing the battery.,
For the guys who are using PC680's this battery;
https://www.pegasusautoracing.com/productdetails.asp?RecID=9404
seems to offer a lot of performance for 2.5 lb and the price doesn't
reflect the usual "aircraft mark up".
Here is the company's web page and I've attached their instructions
and warranty information.
http://www.ballisticparts.com/products/batteries/batteries.php
Does this all make sense or is it so much hokus pokus?
Without a doubt, these batteries perform
as advertised. So did the batteries in the
787.
The uncertainty about this an all lithium products
contemplated for use in vehicles is their plug-n-play
compatibility with SVLA batteries. Do a google search
on 'lithium motorcycle battery' . . .
http://tinyurl.com/kpkjqv3
A number of these products feature battery maintenance
connectors for attaching a specialized tool. Yet
NONE of the advertising hype speaks to the value
or requirement for this connector and the tool that
attaches there. I think the Boeing 787 battery has
become one of the world's most monitored (and
pampered) battery with maintenance/monitor wires
attached to every cell.
Herein lies my discomfort. If these products were
truly plug-n-play replacement for Ni-Cad and/or
SLVA, then this maintenance connector would not
exist, nor anything like a lithium-specific charger.
We see a similar thing with battery charging offers
from the likes of Schumacher with their battery
selector switches labeled SLVA, Flooded, Gel-Cell,
Deep Cycle, etc etc.
Bottom line is that the electrical systems in our
airplanes DO NOT feature mulit-conductor maintenance
connectors that mate with the smart connector on
this or any lithium product.
Nor do our regulators feature any selector switch
for tailoring system performance to SVLA, flooded,
deep cycle, -OR- LITHIUM batteries.
I cannot tell you that I KNOW and UNDERSTAND the
suitability of any of these lithium products for
use on your airplane. I do see unexplained features
unique to the lithium battery manufacturing and
marketing that suggests the batteries are not
drop-in, plug-n-play replacements for the legacy
SLVA battery.
I DO know that SVLA batteries have a comforting
track record and they do not go into fits of
failure or fire when MILDLY abused by the vagaries
of conditions encountered in millions of vehicles
not the least of which are airplanes.
Some years back I was motivated to withhold my
recommendation for installing un-modified, internally
regulated alternators. So too must I be circumspect
about the lithium batteries in airplanes. There
was never an argument with a stock automotive alternator's
ability to perform as advertised. I DID KNOW and UNDERSTAND
their inherent failure modes. Similarly can we
expect the lithium products to be as energetic and
light weight as they claim. In this instance my
reservations are based upon what I DON'T KNOW about
the batteries . . .
(1) and NOBODY KNOWS about their historical performance in airplanes . . .
their history is a tiny fraction of that we understand
about SVLA.
(2) Should we be considering some new regulator design
that plugs into the maintenance connector on these
batteries?
(3) I do know that early drop-in replacements
for SVLA proposed on biz-jets INCLUDED internal battery
monitoring and maintenance electronics.
(4)If Boeing finds value in doing it, should we adopt the
philosophy?
Take one of these batteries apart . . .
Emacs!
. . . and you find something like this inside.
Emacs!
If the suppliers of lithium products onto my grandson's helicopter
find value in perhaps doubling the price of a toy battery
to shepherd it's life in the consumer wild, how is it
that other lithium products can be offered into
operating conditions that are at least as abusive
if not more so?
In the best of all worlds, somebody would finance an
investigative activity into the claims for plug-n-play
capabilities of lithium products onto airplanes.
At the present state of my knowledge, I haven't got a clue.
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|