Today's Message Index:
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1. 09:03 AM - Re: Battery Cap Tester (jonlaury)
2. 09:30 AM - Re: Re: Battery Cap Tester (Robert L. Nuckolls, III)
3. 03:07 PM - Re: Battery Cap Tester (Robert L. Nuckolls, III)
4. 03:44 PM - Re: Battery Cap Tester (Bill Putney)
Message 1
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Subject: | Re: Battery Cap Tester |
[quote="nuckolls.bob(at)aeroelect"]At 11:01 AM 7/11/2013, you wrote:
>
>
>
> (snip).....
>
> How old was the battery when this event occured?
>
> What are you using to charge the battery? Is it a smart
> charger with a bulk/top-off/sustain profile?
>
> This accelerated self-discharge doesn't sound good
> but it MIGHT be that your charger isn't topping
> the battery off. Does it still crank the engine?
> Have you conducted a cranking load test (how many
> amps delivered after 15 seconds loaded down to
> 9 volts)?
>
> If it's still cranking the engine, then the battery
> should top off in flight with a bus of 14.4 to 14.6
> volts. But if the OCV drops that fast, then it's
> almost a certainty that the battery is crippled.
>
> I've moved the po' boy's battery cap checker to
> the front of the bench but its going to be awhile
> before it's in a practical state of utility for
> you. If you're flying this battery, you need some
> faster data. Clip a 55w head-lamp bulb across the
> battery and come back in 2 hours to check the
> voltage.
>
> http://tinyurl.com/kgkxw3l
>
> If it's not at 11.0 volts or above, the battery
> is toast.
>
>
>
> Bob . . .
Bob,
The battery was installed about 4-5 months before the pitot drain down occurred.
It was being maintained by a Schumacher XC-10, set for 'Gel cell' per Schumacher
recommendation after 'AGM' setting was pushing over the Odyssey max voltage
of 15.5v.
When the battery is topped off at about 13.5 volts, it readily spins the 6cyl,
350 ci Franklin with 10.5 : 1 compression through about 4, 5-7 sec start attempts
before getting tired and at rest voltage starts sagging.
Yesterday, after 24 hours on the XC-10, votage was at 14.67v.
After disconnect and about 1.5 hrs, it was at 14.04v.
I'll check it todayand I'll do the lamp test across the terminals too, and report.
Thanks,
John
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=404601#404601
Message 2
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Subject: | Re: Battery Cap Tester |
Bob,
The battery was installed about 4-5 months before the pitot drain
down occurred. It was being maintained by a Schumacher XC-10, set for
'Gel cell' per Schumacher recommendation after 'AGM' setting was
pushing over the Odyssey max voltage of 15.5v.
When the battery is topped off at about 13.5 volts, it readily spins
the 6cyl, 350 ci Franklin with 10.5 : 1 compression through about 4,
5-7 sec start attempts before getting tired and at rest voltage starts sagging.
Yesterday, after 24 hours on the XC-10, votage was at 14.67v. After
disconnect and about 1.5 hrs, it was at 14.04v.
That's not a 'bad' value. There is a period of time
after charger disconnect until the battery terminal
voltage falls to its nominal resting value. There
are small variations between lead-acid technologies
but they'll generally fall into this range of values.
Emacs!
These values are accurate only after a considerable 'resting
interval' for removal of either a charger or a load . . .
a 6-hour rest before measurement is probably reasonable.
The fact that it will deliver 4 cranking cycles suggests
that the battery is not seriously degraded . . . but a new
we tested a new 18 a.h. battery on a high compression
competition engine at 6 or 7 robust start cycles.
Sounds like your battery is wounded but still serviceable.
The self-discharge rate seems excessive . . . a reasonable
hypothesis is that it's a symptom of the 'wounding'. Unless
your design goals dictate that the battery support a
e-bus for several hours, this battery may service your needs
for some time.
>I'll check it todayand I'll do the lamp test across the terminals
>too, and report.
Good move. Have you established an endurance load requirement
for how you use your airplane?
Bob . . .
Message 3
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Subject: | Re: Battery Cap Tester |
Hi John,
>
> Funny you should mention that. I've been on an archeological
> dig on the workbench and uncovered a nicely fabricated
> po' boy's cap checker sent to me for troubleshooting . . .
Made a few drill chips this afternoon and got all the
hardware mounted on the proof of concept Bat Cap Checker.
Emacs!
Emacs!
All the holes have been plugged with screws. It's
time to stuff the board and wire it up.
This version is configured to run a battery down using
the chosen load . . . in this case 3x55w lamps.
When the test terminates, the lights will go out,
the relay will drop and connect a charger to the
battery for replenishment. Touching meter leads
to BAT- and MTR+ will yield a voltage reading
between 0 and 5 volts. 5 volts = 5 hours of
endurance.
Bob . . .
Message 4
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Subject: | Re: Battery Cap Tester |
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