wondering  what size Min-Kota  would  equal a 3 HP gas outboard.
And where might I find a counter rotating  version?  < grin>
Might as well  try and  use  all those dead batteries I resurrected with my
pulse device.  < bright idea! >

Now there's a picture!
Arild surrounded by resurrected batteries in a rubber boat running an
electric motor that doesn't know whether it is coming or going but is
counter rotating.
Will that be one pulse or two?
One pulse one is a two step charge?
Richard ;^))))

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capnrich31@home.com writes:

I suddenly remembered that in one of my earlier incarnations - before
transistors replaced tubes - my college instructor said that it was
better for a batterie charger to leave the raw D/C 'as-is' fresh out
of the diode rather than smoothing the pulses with an R/C network.
Supposedly this would "shake" up the plates and loosen deposits
(sulphate?).

Seems to me that these much talked about batterie pulsers are perhaps
just that: unfiltered raw D/C fresh out of a half-wave rectifier?

I don't have an oscilloscope anymore (my 453 retired along with it's
owner some years ago),
but perhaps someone on this list could hang a scope on the output of
their rejuvenating pulser and tell me the frequency, waveshape and
amplitude of these pulses. I'm almost willing to bet that a  small ca
12 volt transformer with a 40H (or so) diode would do the trick.

Obfuscatingly (just for Richard) - George of Scaramouche

I put a scope on the output of the pulsing desulfator a friend and
built.  It is definitely a narrow pulse with a relatively long rest time
until the next pulse.  And the pulse amplitude was a little in excess of 20
volts.  A little portable battery AM radio held next to it will buzz like
hell!  Don't have details of the pulse parameters here with me
though.  Also, have a commercial AC powered de-sulfator, but haven't looked
at it with a scope yet.  It seems to be reviving a truck camper batter
though.  Camper batteries get ignored more than boat batteries, so die more
often due to sulfation.

I initially suspected the circuitry was the same as your were
thinking.  But, the power line pulse rate from a unfiltered rectifier is
too low and too high of duty cycle to "pluck the strings" of the battery's
internal resonate frequency.  It would, however, charge the battery.  The
patent for the pulsing technology was issued in 1975... I think.

As I indicated in a previous post, there is no cost benefit in building
your own de-sulfator.  We spent the same amount for parts and then had the
time investment of building and testing it.

We had more fun though.  We (my fellow boater and I, both retired) are also
from the days of vacuum tubes and "valves."  I still  have an old "01A"
"valve" in my collection. ;-)

Ben Lewis and Mary Wilson
"BenGeM"  34' 1981 CHB Trawler
Poulsbo Yacht Club, Poulsbo, WA
blewis@oz.net

At 07:36 AM 4/6/01, George Geist wrote:

blewis@oz.net writes:

Thanks for the info. Have no intention of building my own. Just old
habit to always wanting to know how things work. Hmm resonant
frequency of the lead-plates. Haven't heard that expression before
but makes good sense. Now where is that variable tuning fork I once
bought to do my daughter's piano....  :-)

Actually I tried to buy a de-sulfator here in Toronto, but all I get
is stares as in "which planet are you from?". I got a lead on a
company in Winnipeg, Manitoba but they want $200 for one (that's the
cost of two good deep-cycle batteries). No-one here has heard of
either the tool or the chemical which was also discussed on this
list. I will probably order a unit from the U.S. even though that
irks me with our unfavourable exchange rate and high shipping cost
and of course the hassle at Canada Customs.

Thanks again for your advise - George of Scaramouche

Hey, I remember hearing the same thing from a prof about chargers...but that
was also pre-IC.

There are several different circuits now being sold on the market.  So far
as I am aware (we researched before buying), they are all similar in
concept.  Take a look at http://shaka.com/-kalepa/desulf.htm.  Here is how
it works.

Lay version: the circuit draws a very small amount of electricity from your
battery for about a millisecond.  Then it sends a high voltage, high current
spike of very short duration into your battery.  The cycle repeats
indefinitely.  Because the pulse is of such short duration, it cannot hurt
the battery.  There are various explanations as to why it can remove
sulphation from the battery.  One circuit variation is that it includes a
small internal charger; I've seen both mains and solar powered offered.

Techie version: The circuit is a switching DC-to-DC converter that steps the
battery voltage up to a higher level in pulses. The basic pulse rate (about
1kHz) is set by a timer chip, typically a 555. One variation has the pulse
rate sweeping back and forth. The timer switches a MOSFET; when in the
non-conducting state, current is drawn from the battery to which the circuit
is connected through a tapped coil to charge a capacitor. The MOSFET turns
on for about 50 uS, causing the charge stored in the capacitor to flow
through the coil, building up emf.  When the MOSFET is next turned off, the
stored inductive energy in the coil collapses and sends a high voltage
(about 60-volts in mine), high current (in mine supposedly over 10-amps)
pulse back into the battery through a diode.

That's it!  All I really know is that it seems to work.

Maurice & Louise-Ann Nunas
M/V AKAMA
Pier 2, Ponggol Marina
Singapore

-----Original Message-----
From: owner-trawler-world-list@samurai.com
[mailto:owner-trawler-world-list@samurai.com]On Behalf Of George Geist
Sent: April 6, 2001 10:37 PM
To: capnrich31@home.com
Cc: trawler-world-list@samurai.com
Subject: TWL: Batterie Pulsar was Dinghy/motor question

capnrich31@home.com writes:

I suddenly remembered that in one of my earlier incarnations - before
transistors replaced tubes - my college instructor said that it was
better for a batterie charger to leave the raw D/C 'as-is' fresh out
of the diode rather than smoothing the pulses with an R/C network.
Supposedly this would "shake" up the plates and loosen deposits
(sulphate?).

Seems to me that these much talked about batterie pulsers are perhaps
just that: unfiltered raw D/C fresh out of a half-wave rectifier?

I don't have an oscilloscope anymore (my 453 retired along with it's
owner some years ago),
but perhaps someone on this list could hang a scope on the output of
their rejuvenating pulser and tell me the frequency, waveshape and
amplitude of these pulses. I'm almost willing to bet that a  small ca
12 volt transformer with a 40H (or so) diode would do the trick.

Obfuscatingly (just for Richard) - George of Scaramouche

Nunas@pacific.net.sg writes:

Dear M & L Nunas:

After reading your techie version of the pulse-circuit ("Pulsar" was
an attempt at humour, but no-one seems to want to pick on me today),
I retract my above statement. I thank you for the explanation - I
actually understand this (used to be a mainframe computer techie).
Now if the output is simply a short duration spike of about 60 volts,
why not take line voltage A/C through a limiting resistor and an SCR
with a very short trigger. No transformer, no coil, no MOSFET,
nothing but simplicity... Think I'll work on that as a winter project
maybe next year or the year after that or so.

Procrastinatingly - George of Scaramouche