battery self-destruct

Hi,

My airplane has a Gill G-35 battery in it. The battery is less than 3
years old. We did a 10-minute run up about 2 weeks ago. The plane has been
sitting in it's hanger for the last 2 weeks. The master switch was OFF and
the battery was NOT on a charger.

Today I went to use it, and found a puddle of acid underneath the plane
where it had dripped out of the battery box vent tube. Battery voltage
indicated 8.3 volts. Took it home and examined it. The middle four cells
each were full, the end two cells were low -- one about 70% full and the
other about 90% full.

Placing a load-tester on the battery causes one of the cells to start
boiling.

Can anyone tell me what the heck went wrong with the battery? I'm assuming
it's shot and needs replacement. Temperature here is mild (50-80 degrees
F). Humidity is high. I've never seen this happen to a lead-acid battery
before....

Thanks

-----------------------------------------------------------
Posted using Android Newsgroup Downloader:
.... http://www.sb-software.com/android
-----------------------------------------------------------

wrote:



Can anyone tell me what the heck went wrong with the battery? I'm assuming
it's shot and needs replacement. Temperature here is mild (50-80 degrees
F). Humidity is high. I've never seen this happen to a lead-acid battery
before....

That battery is toast. Anytime the level of the electrolyte falls below
the top of the plates for any but the shortest amount of time the
battery is wrecked.

These batteries build up lead oxide on the plates and need to be slow
charged from time to time to rejuvenate. Try to find a trickle charger
that will put out about one ampere and try charging for several days.
If you let a lead acid stand too long it will develop oxide on the
plates and not come up to full charge. The battery should reach 13.8
volts when fully charged.
Also, be certain to neutralize the spilled acid in the airplane
battery area with baking soda solution.

Thanks for the note. 2-amp is the lowest that I have, so I'm giving that a
shot and will let you know what happens.

I'm still unsure just what caused the problem in the first place -- I'd
like to know how to prevent this from happening again in the future, be it
with a new battery, or with this one if it survives.

From my viewpoint, all this happened while the plane was just sitting
there [things breaking while "just sitting there" seems to be a common
failure mode of airplanes...] Could it have been that the battery got
overcharged during that 10-minute run-up that I made 2 weeks ago? i.e.
battery was low, and the 10-minute run-up gave it a whopping big charge,
and I didn't notice the acid spillage until today?

These batteries build up lead oxide on the plates and need to be slow
charged from time to time to rejuvenate. Try to find a trickle charger
that will put out about one ampere and try charging for several days.
If you let a lead acid stand too long it will develop oxide on the
plates and not come up to full charge. The battery should reach 13.8
volts when fully charged.
Also, be certain to neutralize the spilled acid in the airplane
battery area with baking soda solution.


-----------------------------------------------------------
Posted using Android Newsgroup Downloader:
.... http://www.sb-software.com/android
-----------------------------------------------------------

The general rule for battery charging to get the most life out of them
is to charge at ten percent of rated capacity and trickle charge at one
percent. So for 35 AH battery the best charge rate would be 3.5 amps
and trickle charge at 350 milliamperes.
If the battery voltage is below 12 volts and you start the engine
and induce a high charge of say twenty amps it will cause cavitation
and result in oxide coming off the grid, piling up in the bottom of the
cells and shorting out the battery.
I do not leave the battery in my Cherokee for periods of time over
three weeks. I bring it home and place it on trickle charge.

Obviously, replace the battery... Obviously give the battery a constant
current charge before installing... Obviously, use baking soda and
copious water flush on the battery box, belly of the plane, etc.,
before installing the new battery...

Go to the auto store and get a voltage meter that plugs into the
cigarette lighter... Plug it into the lighter receptacle, or otherwise
get it hooked up... Turn the master on (all radios off) and notice the
voltage... Now start the engine (alternator switch is off if possible)
Once the engine is running and/or the alternator switch turned on
immediately note the voltage... If it is higher than 15 volts
immediately shut the alternator off, or stop the engine, as you have an
overvoltage condition... If the voltage is high do not run the engine
for ten minutes, but get a mechanic to help you... Yes, ten minutes of
overvoltage can ruin a battery...

If the charge voltage is normal after starting the engine up, mid to
high 14 volt range, then assume the battery just spontaneously went
shorted as one of those strange things that happen... Murphy never
sleeps...

denny

If the battery is 3 years old I probably wouldn't have even bothered
trying to mess with the battery. After a few years of ownership now I
replace my battery every 2 years. Seems to avoid a lot of hard starts
that seem to appear out of nowhere leaving you stuck somewhere.

-Robert


wrote:
Hi,

My airplane has a Gill G-35 battery in it. The battery is less than 3
years old. We did a 10-minute run up about 2 weeks ago. The plane has been
sitting in it's hanger for the last 2 weeks. The master switch was OFF and
the battery was NOT on a charger.

If shorting the battery,and you see bubbles in any cell means your
battery has a shorted cell and a charge will not last.It might start if
you don't let it stand very long.In other words, you'll have to keep
flying,Oh what a live! LJ

Robert M. Gary wrote:
If the battery is 3 years old I probably wouldn't have even bothered
trying to mess with the battery. After a few years of ownership now I
replace my battery every 2 years. Seems to avoid a lot of hard starts
that seem to appear out of nowhere leaving you stuck somewhere.

-Robert


wrote:

Hi,

My airplane has a Gill G-35 battery in it. The battery is less than 3
years old. We did a 10-minute run up about 2 weeks ago. The plane has been
sitting in it's hanger for the last 2 weeks. The master switch was OFF and
the battery was NOT on a charger.

"Robert M. Gary" wrote in message
ups.com...
If the battery is 3 years old I probably wouldn't have even bothered
trying to mess with the battery. After a few years of ownership now I
replace my battery every 2 years. Seems to avoid a lot of hard starts
that seem to appear out of nowhere leaving you stuck somewhere.

-Robert

With proper care they will last much longer. Mine is 6 years old and still
going strong. Keep the posts clean and corrosion free, water at the proper
level and the battery charged without using a high amp charger and they will
last a long time. Keeping the engine in tune, keeping the battery warm in
the winter and using the proper starting procedure also helps

LJ writes:

If shorting the battery,and you see bubbles in any cell means your
battery has a shorted cell and a charge will not last.It might start if
you don't let it stand very long.In other words, you'll have to keep
flying,Oh what a live! LJ

Actually, I suspect it's reversed. That means the discharge current
is charging that cell...

In any case, the battery is "He's DEAD, Jim..!"

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433