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| Title: | Powerboats |
| Notice: | Introductions 2 /Classifieds 3 / '97 Ski Season 1267 |
| Moderator: | KWLITY::SUTER |
|
| Created: | Thu May 12 1988 |
| Last Modified: | Wed Jun 04 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1275 |
| Total number of notes: | 18109 |
770.0. "Wierd (pun) battery...." by CSDPIE::THACKERAY () Sun Nov 18 1990 11:00
Cross-posted from SAILING:
I feel like my battery has crossed through to an alternative universe
and warped back, but in reverse.
After two years of service, my 105 a/h marine battery, having recently
displayed a minor deterioration in a couple of its cells, has suddenly
reversed its polarity!! Although the battery was badly discharged when
I got to it yesterday to recharge it, when I connected it to the
battery charger, the meter on the charger went nutso, and I got a big
spark when I connected the terminals.
No, I didn't get them crossed.
After some minutes of confusion, I connected the terminals the WRONG
way, and the battery started charging, and displaying all the correct
characteristics!! By this time, I'm thinking that someone has played a
joke on me and reversed my charger connectors. So I went to one of my
other batteries, which I know is connected correctly because it's
driving the Loran-C OK.
Connecting the correct way, the battery is fine, the charger is fine!
Then I went to get a voltmeter.
Sure enough, my battery has reversed its polarity!!!!!!! Each cell,
although under poor charge, is roughly equivalent in specific gravity.
I haven't tried to charge the thing up fully yet, in this reversed
condition, because without knowing what strange chemical changes it has
undergone, I don't want to blow myself up.
Does anyone have any idea what is going on here? Or should I just
accept that there is a black hole inside my battery and carry on
regardless?
Befuddled,
Ray
| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 770.1 | Discharge and recharge slowly | SALEM::NORCROSS_W | | Mon Nov 19 1990 08:41 | 10 |
| Ray, I have no idea how your battery could have reversed polarity all
by itself but I can remember my father taking a "dead" battery to a gas
station when I was a kid. They recharged the battery backwards by
accident. The fix was to slowly (!!!) discharge the battery until it
was totally dead again and recharge it correctly. Didn't seem to have
any long term affect on the battery. Discharging and recharging SLOWLY
was the most important thing. Assuming that you are running an
isolator with the dual batteries, I would certainly check that out as a
possible cause.
Wayne
|
| 770.2 | Try it | EXPRES::GILMAN | | Wed Nov 21 1990 10:49 | 9 |
| I have never heard of a lead/acid battery reversing polarity by itself.
If it was charged backwards for an extended time I could see it. Was
it charged in reverse that you know of.
You have nothing to lose by trying the discharge till flat SLOWLY then
recharging SLOWLY with the correct polarity. The worst that will
happen is that you will have to replace the battery. Nothing to lose
everything to gain. Try it. Let us know what happens.
Jeff
|
| 770.3 | First hand experience... | CSOMKT::BOSELLI | | Thu Nov 22 1990 13:17 | 13 |
| I had a 1966 Corvette which I bought about 5 years ago. After using it
for a year or so, I started having peculiar electrical problems.
$1,000 later, the mechanic discovered that the battery was
installed with reversed polarity.
He put in a new battery, fixed the voltage regulator and everything was
fine from then on.
I took the old battery, scratched off the "+" and "-" signs on the
terminals, taped on new positive and negative labels and used it in my
boat for 3 more years!
I don't understand it either...but it worked.
|
| 770.4 | | BTOVT::JPETERS | John Peters, DTN 266-4391 | Mon Nov 26 1990 16:08 | 19 |
| A battery will charge up in any direction.
If it has one or more weak cells, and one goes dead followed by pulling
more current from the battery, the remaining cells charge the dead cell
in reverse.
If you posit three strong cells and three totally discharged cells, and
pull a load, there's a point at which the battery switches polarity.
At the point at which the cells get imbalanced enough to start behaving
like this, it's time to replace the battery (of course, you can nurse
it along as long as your life doesn't depend on it... in a boat, I
figure that my life may depend on it.).
A reverse charged battery will have less capacity and a shorter
lifetime than a forward charged battery due to subtleties like plate
geometry and chemistry.
|
| 770.5 | and polarize that generator... | SALEM::LAYTON | | Tue Nov 27 1990 08:04 | 7 |
| I vaguely recall rebuilding a generator (not an alternator) and being
told to "Polarize" it by attaching a battery to the terminals cuz if
you didn't, it would work backwards (+ would be -, etc.). I'll bet
that reversed batteries were more common in the old days before
alternators.
Carl
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