nuckolls.bob(at)aeroelect
Guest
|
 Posted: Thu Apr 15, 2010 9:24 am Post subject: Battery maintenance philosophies to meet design goals |
 |
|
| Quote: | If I'm going to ask an opinion of someone on the list, then I certainly must provide accurate information - or expect no answer.
I'm using Odessey and happy with it so far. I have no intention of changing at this time. But, I was interested in the answer to the proposed question. I am always interested in a less expensive, but adequate replacements for equipment.
Perhaps changing a battery each year is a waste of money. And I've been called an old FUDdy before, but it is certainly not out of fear, uncertainty, or doubt.
I change a battery a year because:
1. It is recommended by an expert in the field - Electric Bob |
I did NOT recommend it. I suggested it as
an option to be considered and adopted pending
YOUR assessment of design goals, ways in which
you choose to spend your $time$ and tools you
plan to acquire to execute a considered preventative
battery maintenance program.
| Quote: | | 2. My ignorance dictates that I listen to the experts |
I'd rather you use my offerings more as teacher
than as expert. If you don't understand the
fundamentals upon which best decisions are made,
then you are at risk for falling victim to anyone
who wraps themselves in the mantle of "expert"
| Quote: | | 3. It establishes a reasonable means to avoid failure |
Let us assume you're going to buy a Hawker-Enersys
super battery of some kind and you plan to run
it until no longer suitable for flight? What
criteria and tools to YOU plan to use to monitor
that condition? Whether you swap every year
or run it until no longer suited for flight,
the means by which you avoid 'failure' lies
entirely in your lap, not the suggestions
of anyone else on the list.
| Quote: | | 4. It is not overly expensive |
If it's not the LEAST expensive, then
don't do it.
| Quote: | | 5. The batteries are used in other equipment and not wasted. |
Can you quantify "wasted"? Let's say you install
a shiny new 18 a.h. battery and your endurance
analysis shows that you need 12 a.h. at a 3 hour
rate to meet your battery only endurance goals.
When it's time to replace that battery, it will
still be cranking the engine just fine. When you
swap out an el-chesso battery at one year, it
too will still be cranking the engine just fine.
Both scenarios will remove a battery from your
AIRPLANE that may still have some degree of
usefulness NOT in an airplane. Which scenario
offers the most/least "waste"?
| Quote: | | 6. The oldest battery at any moment in my RV is 2 years. |
So is the main battery (which I presume was new
last year) going to replace the 2-year old
aux battery soon?
| Quote: | | 7. I don't have to bother with capacity checks |
I prefer to express it differently. You battery
preventative maintenance program is optimized
to expend the minimum $time$ to insure compliance
with your design goals.
| Quote: | | I also change my tires before they fail. Anyone who wants the old ones just let me know. |
Boy . . . do I remember those days! There was a
Texaco station owner who took pity on me and
gave me a call when he had extra-ordinarily
meaty take-off tires I could buy.
| Quote: | | I change my hoses before they fail. Anybody want the old ones? |
Naw . . . ran too many of those until they blew . . .
| Quote: | | I don't like being stranded in remote locations because I tried to stretch the life of consumables such as batteries. |
In this case, the "stretching" thing doesn't have
much tension in it. Unless you're installing big lead
pigs with the idea that your battery-only endurance
requirements can be met with only 25% of as-new capacity,
then maybe you would stretch it.
Now, Z13/8 does offer an opportunity to take battery
capacity completely out of the FMEA study for
endurance. Cranking the engine is a pretty good test
of a battery to be MINIMALLY functional where a second,
engine driven power source replaces the battery as
the stand-by power source.
| Quote: | | Just call me an old fuddy. |
Old fuddies are those among us who allow our airplanes
to get WAAaaayyyy ahead of us. For many of our brethren
in the TC aircraft world, the airplane is probably too
far "out in front" . . . and they don't have to be grey-
haired to suffer this condition! This assertion is supported
by the many dark-n-stormy-night stories we've read and analyzed
on the List over the years.
I'll respectfully suggest that if folks are participating
here just to ask for and run with an answer that appears
delivered with some expertise, you may be better off
sticking with a C-172 style electrical system. The value
to be gathered here is not the advise of experts or
a mass of anecdotal experience. It's my fondest wish that
folks flying systems crafted from ideas offered here
UNDERSTAND what's going on and are in command and control
of their electro-whizzy destiny.
| Quote: | Ira, thanks for researching the correct info on the battery and providing your opinion. I appreciate it.
It appears from your comment that you prefer Panasonic batteries. Which model do you use? Why do you believe that battery is better than an Odessey? |
Panasonic makes no product on a par with Hawker-
Enersys. My studies of aircraft battery products
have convinced me and my colleagues that H-E
products are the cream of the battery crop. In no
way should that statement be interpreted to mean
that Panasonic products do not offer good value.
Only the builder/operator of an OBAM aircraft
can make the determination of value based on their
own cost-of-ownership studies.
| Quote: | | Does it have more AH capacity? Does it have faston tabs or screw on terminals? |
There's a collection of battery manufacturer's
data including Panasonic and H-E on my website
at:
http://aeroelectric.com/Mfgr_Data.html
| Quote: | | Your suggestion of replacing a battery every two years seems like a reasonable thing to do - especially if one charges the batteries to capacity periodically. |
How do we quantify "reasonable" . . . how many
watt seconds of energy are expected to be contained
in an 18 ah battery after 2 years of "reasonable"
use and maintenance?
Please don't think I'm picking on you my friend.
I think it's important that words be crafted to
illustrate well considered recipes for success.
It's important that meaning/understanding is not
sacrificed to misinterpretation.
Bob . . .
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
