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'[OT]Referbishing solid gel type batter for robot p'
1998\10\30@112214 by Craig Lee

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So we are trying to enter a BEAST into the Southern Alberta
Robot Games competition in Calgary (in two weeks).

Well I have a couple of big 6V gel cells, but they won't seem
to charge.  I bought them a few years ago from Princess Auto,
and never tested them.

Is there a way to revive them?
Does the gel crystalize?


Craig

1998\10\30@144007 by Matt Bonner

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Craig Lee wrote:
>
> So we are trying to enter a BEAST into the Southern Alberta
> Robot Games competition in Calgary (in two weeks).
>
Craig,

Where and when is the competition?  I'll come by and cheer you on.

--Matt

1998\10\30@144628 by Matt Bonner

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Craig Lee wrote:
>
> So we are trying to enter a BEAST into the Southern Alberta
> Robot Games competition in Calgary (in two weeks).
>
> Well I have a couple of big 6V gel cells, but they won't seem
> to charge.  I bought them a few years ago from Princess Auto,
> and never tested them.
>
> Is there a way to revive them?
> Does the gel crystalize?
>
Whoops - pressed "send" to fast on the previous reply.  We've fixed
"Gates" gel cells in the past - set your power supply to double the cell
voltage and current limit it to 4 or 5 times the normal charge rate.
Zap them for a few seconds and then attempt to charge normally.  It
doesn't work all the time and I'm not sure if you'll get full the
capacity back.

--Matt

1998\10\30@150459 by Craig Lee

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It's at SAIT.  I found out a week ago that anyone can enter, not just
students or alumni.  So we are fashioning this challenge to build
a bot in 2 weeks.....FROM SCRATCH!!

I am going to name it 'NEWCOM FOR PRESIDENT'.
(read SCIAM, October 1998 for why.... to paraphrase... sometimes)
(it takes complete novices to multiply the innovation factor; a fresh
perspective )

I'm sure other piclisters will be there too.  See http://www.robotgames.com
for details on the date, and the rules.

Craig

{Original Message removed}

1998\10\30@150715 by Craig Lee

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They are 6V bats and I tried a 12V, 500mA supply across.

Next step, 24VAC! (sadistic 'Uncle Fester' laugh)

Craig

{Original Message removed}

1998\10\30@152352 by Dave VanHorn

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Craig Lee wrote:
>
> They are 6V bats and I tried a 12V, 500mA supply across.
>
> Next step, 24VAC! (sadistic 'Uncle Fester' laugh)


I've had good luck restoring "sleeping" gels with reverse voltage
through a current limiter (light bulb) Up to 30V in reverse, until some
significant current flows, then back to normal polarity until the charge
current drops off.
(sounds like a PIC controller project!)

Repeating this as many times as needed. Once it seems to not need the
reverse voltage, then give it hard discharges, and recharge as fast as
practical (without exceeding 2.55 V/Cell)

Good luck!

(I'm trying to do much the same now, with a bank of 400AH wet cells that
we hope to use for our ham repeater backup, otherwise, it's off to the
hospital to beg some retired cells)

1998\10\30@152808 by Peter L. Peres

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On Fri, 30 Oct 1998, Craig Lee wrote:

> They are 6V bats and I tried a 12V, 500mA supply across.
>
> Next step, 24VAC! (sadistic 'Uncle Fester' laugh)

Actually that could blow up in someone's face given enough current. These
batteries take horrible amounts of current and it should be forbidden by
law to use them without a bimetallic limiter.

Also, if they dry out, a squirt of aqua dest. will restore them to
life. The Gates 2V cells take about 5 ml and overnight soaking if I
remember well. be aware that this can ruin them completely however, and
don't short the plates with the syringe needle.

They appear shorted if dead by material migration and open if dried. You
already know the cure for the 1st symptom ;)

Peter

1998\10\30@154023 by Matt Bonner

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Craig Lee wrote:
>
> It's at SAIT.  I found out a week ago that anyone can enter, not just
> students or alumni.  So we are fashioning this challenge to build
> a bot in 2 weeks.....FROM SCRATCH!!
>
> I'm sure other piclisters will be there too.  See http://www.robotgames.com
> for details on the date, and the rules.
>
According to that page, the competition has been moved from SAIT to the
Calgary Science Centre.

--Matt

1998\10\30@155941 by The Plumber

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On the robotgames hompage, and on the advertisement at Active components
it says it's at the Calgary Science Center (AKA Planetarium), games start
at 10:00.

Thanks,
Joe Hoffmann
E-Mail spam_OUTjhoffmanTakeThisOuTspamit.sait.ab.ca

On Fri, 30 Oct 1998, Craig Lee wrote:

{Quote hidden}

> {Original Message removed}

1998\10\30@160106 by Mark

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> It's at SAIT.  I found out a week ago that anyone can enter, not just
> students or alumni.  So we are fashioning this challenge to build
> a bot in 2 weeks.....FROM SCRATCH!!

No, it's not. It's at the Calgary Science Centre (Planetarium). The
website (http://www.robotgames) is correct though.

Trust me, I'm on the organizing committee :-)


Mark Hillier
President, HVW Technologies
.....MarkKILLspamspam@spam@HVWTech.com
Tel:(403)730-8603 Fax:(403)730-8903
Visit our web site: http://www.hvwtech.com

1998\10\30@184816 by Dwayne Reid

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>Well I have a couple of big 6V gel cells, but they won't seem
>to charge.  I bought them a few years ago from Princess Auto,
>and never tested them.
>
>Is there a way to revive them?
>Does the gel crystalize?
>
>
>Craig

Sorry Craig - in all the years that I've been playing with gel cells, I've
never found a way to revive damaged batteries.


dwayne


Dwayne Reid   <dwaynerspamKILLspamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(403) 489-3199 voice     (403) 487-6397 fax


'[OT]Referbishing solid gel type batter for robot p'
1998\11\02@001735 by tjaart
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Matt Bonner wrote:

> Craig Lee wrote:
> >
> > So we are trying to enter a BEAST into the Southern Alberta
> > Robot Games competition in Calgary (in two weeks).
> >
> > Well I have a couple of big 6V gel cells, but they won't seem
> > to charge.  I bought them a few years ago from Princess Auto,
> > and never tested them.
> >
> > Is there a way to revive them?
> > Does the gel crystalize?
> >
> Whoops - pressed "send" to fast on the previous reply.  We've fixed
> "Gates" gel cells in the past - set your power supply to double the cell
> voltage and current limit it to 4 or 5 times the normal charge rate.
> Zap them for a few seconds and then attempt to charge normally.  It
> doesn't work all the time and I'm not sure if you'll get full the
> capacity back.

They should have 10 year guarantees, so maybe you can swop
them for new ones.

--
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1998\11\21@145128 by Andrew Russell Morris

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At 06:48 PM 10/30/98 -0500, you wrote:
>>Well I have a couple of big 6V gel cells, but they won't seem
>>to charge.  I bought them a few years ago from Princess Auto,
>>and never tested them.
>>
>>Is there a way to revive them?
>>Does the gel crystalize?
>>
>>
>>Craig
>
>Sorry Craig - in all the years that I've been playing with gel cells, I've
>never found a way to revive damaged batteries.
>
I'm sorry for the long response time, but I got behind in my PICLIST
reading. I've sucessfully revived Gates gel cells and I've been using them
for about 15 years afterward. They still work. First of all, you need a
charger with automatic shut-off, designed for lead-acid batteries. I
designed my own and I leave the batteries on it all the time when not in
use. I intentionally only charge the batteries to about 95% to avoid
overcharging them, which will eventually destroy them. I think that's why
they lasted so long. Put the dead battery pack on the charger and leave it
for DAYS or MONTHS. When the batteries are FULLY discharged, the sulfuric
acid suspended in the gel is almost water and conducts very little current.
I tried increasing the voltage to speed up the process on another battery
pack and destroyed it. DON'T DO THAT! Be patient. You maybe can speed it up
a little by connecting the cells in parallel through current limiting
resistors (one per cell) to a lab supply and stopping the charging when the
cells start to draw any current. Then put them in series and connect them
on the charger. My charger uses an SCR, zener diode and a few small parts
to cut off when the battery voltage got to 13.4V (I think). I have an LED
in series with a resistor, accross the current limiting resistor (.5 amp).
The LED will start blinking when the battery is near full charge. It blinks
about once a second when the battery is full. It takes a few days to come
up to full charge (80% in about a day). I'm sure you can charge it faster.
The SCR trick works so well because the battery develops a "surface charge"
voltage which is higher than the actual voltage and drains off immediately
after the charger cuts off (hence the blinking LED). The SCR cathode (its
gate is held to the Zener referenced voltage .6V above the target charge
voltage) senses only the real charge on the battery and stays on for the
rest of the half-cycle. This is why most lead-acid battery chargers
overcharge batteries (they try to compensate for the unpredictable surface
charge voltage). The temperature coefficient of the SCR and zener
approximate that of the battery. I'd post a schematic of the charger, but
I'm no good at ASCII art and my schematic is in ORCAD (if I can find it).

Even if you've thrown your batteries away by now, I hope this helps someone.

TTFN :-)

1998\11\22@133426 by Craig Lee

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Well I haven't thrown them away yet.

I did fill them full of water though as suggested by a picker, and they
still won't charge.

I'll try a charging circuit.

So if I am reading you correctly, I should design a circuit that removes the
battery from the chargeer at about 5.7V, and limit the charge current to
500mA?

Craig


{Original Message removed}

1998\11\23@221037 by Andrew Russell Morris

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At 11:35 AM 11/22/98 -0700, you wrote:
>Well I haven't thrown them away yet.
>
>I did fill them full of water though as suggested by a picker, and they
>still won't charge.
>
>I'll try a charging circuit.
>
>So if I am reading you correctly, I should design a circuit that removes the
>battery from the chargeer at about 5.7V, and limit the charge current to
>500mA?
No. First, if you filled them full of water, they're probably destroyed
now. In high school (MANY years ago) I did a chemistry project on lead-acid
batteries, designed a charger for them and used them in a portable radio. I
had to learn and document the chemistry behind them. When the batteries are
completely empty, the sulfur from the sulfuric acid suspended in the gel is
now on the plates. The electrolyte is almost pure water. You need to apply
a nominal, current limited voltage (say 5 volts, limited to 100ma) to each
individual cell until the cell starts to draw noticable current. This may
take days, weeks or months. I don't reccommend raising the voltage
substantially to force the process. When the cell starts to draw a bit of
current, the cell will heat substantially and be damaged. When you get 1.5
volts or so on each cell, put them back in series and use an auto-cutoff
charger  designed for lead-acid batteries. If you can't get access to the
individual cells, connect the charger and wait a long time.

I'd try to pour out the water, and flush the cells with distilled water (if
distilled water was not used the first time. Remove all water, and hope the
gel is still intact. With wet cells, you could have filled the batteries
with very weak sulfuric acid and recharged them.

I hope it works for you.
>
>Craig
>
>
>{Original Message removed}

1998\11\27@155106 by Andrew Russell Morris

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part 0 559 bytes
Attached is the schematic of the gel battery charger circuit that has
served me so well for the last 15 years. I hope others can get good use out
of it. It is in HPGL format, A size drawing. Just copy it to your plotter
if you don't have an HPGL viewer. By the way, a free viewer called CAMCAD
is available at http://www.camcad.com. BTW any SCR will do. The circuit is my own
design. Email me if you have questions about it.

I think I accidently resent the old message earlier. Sorry!  TTFN :-)
Attachment converted: wonderland:charger.PLT (HPGL/GKON) (0001F811)


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