Hi Roy
On (13 Oct 96) Roy J. Tellason wrote to Alec Cameron...
 RJ> I've acquired,  recently,  about a dozen or so gel batteries,  eight of
 RJ> them 33 AH units and the other four 10 AH units.  Mostly I've been busy
 RJ> dumping some charge into them...
 RJ> I'm told that the reason they were being disposed of is that they sat on
 RJ> the shelf for too long.  With only one exception,  the seem to be 
howing
 RJ> me good voltage,  though.
 RJ> The part that bothers me about it is the idea of connecting all of these
 RJ> in parallel,  I keep thinking that there ought to be a better way.
I have only a little gel experience, which was with "sick" units and I agree
that charging in parallel is NOT the way to refresh these if they've gotten
ill.
The sick ones I refreshed, were probably sulphated or otherwise highly
resistive. At 2.5v/ cell DC applied from a charger, there was just NO
significant current flow even tho the cells' open circuit voltage was way
under 2.0.
I found it helpful to use an extremely high source voltage of [memory] maybe
20 volts/ cell BUT with a lot of series resistance, to protect the cells [and
charger] if and when the cell v locked in to the normal range 2.0> 2.6 volts.
So at the beginning of the "charge" the cell terminals were reading very
high [over 5v/cell]. As the hours/ days passed, with an input current of 
bout
C/30 the cell v dropped back to about 2.2, slowly increasing to a 
onventional
value of about 2.4. When the volts stabilised, I discharged the cells and 
hen
gave a normal recharge and got OK service thereafter. Probably for a couple 
f
years, in float service, burglar alarm system.
The initial "recharge" at about 20v/ cell limited by resistor to C/30 rate,
was probably a depolarising and sulphate removal process NOT a conversion of
active material from a discharged to a recharged condition. Once the cell
volts had fallen down to 2.2 then I reckon the charging commenced.
The maker name was Gates. Yuasa gel batteries I have used, I have had no
trouble with at all, maybe because I sold the vehicles so equipped, before
battery disorders occurred.
If you have a 6 cell battery reading 10 volts, and if it accepts a decent
charge current from a 12/14v source but refuses to get up from 10 volts then
you probably have a shorted cell. If a gel battery, chuck it out. If it is a
liquid filled one then with rubber gloves and eye protection you might be 
ble
to dislodge the piece of gunk by draining the battery and flush it out with
the garden hose, giving it a lot of bumping while inverted. Let the battery
drain thoroughly after, because the water you flushed with ain't distilled.
Refill with proper electrolyte [you can reuse what you took out, it doesn't
deteriorate] and re charge. You might be lucky!
If you do this in the bath tub then wait till Someone has gone out shopping!!
Cheers....ALEC
... ........The hasty and the slow meet at the ferry
--- PPoint 1.92
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