Re: [Aquarius-owners] Re: pulser desulfater, plus NiCad Info
- Dan, I'm glad your new pulser is working out. Make sure you get your automotive batteries pulsed, too.
NiCads: high frequency pulsers are used to rehabilitated NiCad batteries by breaking up the NiCad crystals into smaller crystals, thus giving more surface area for the battery. NiCad chemistry is completely different from a lead/acid. NiCads form crystals while charging; Lead acid chemistry normally dissolves them as the battery is charged.
The hi freq pulsing erases the so-called "memory".
As the NiCads are continuously recharged, the NiCad crystals reform into larger crystals, which are not as electrochemically active as smaller crystals. NiCads really don't form a memory...Forming larger crystals decreases the power storage ability.
From what I've seen on the net, the pulsing breaks the crystals down into finer and finer crystals. You can also reverse charge the batteries down past the nominal 1.25 volts. What I do is completely run the batteries down, then reverse charge the batteries down to about 1 volt each (on individual batteries) This breaks the crystals down further, than simply completely discharging the batteries.... Caution: Don't reverse charge individual NiCads past 1 volt. The further into negative charging you get, the more probable you will cause the battery to reverse polarity (trashing it).
I know some kids that race model cars, which use NiCads. There are class rule limits to the size of the batteries, so those kids research and try every imaginable way, to increase the performance of the batteries. They hot discharge them, then reverse charge them to the point where one out of five NiCads reverse polarity (ruining it). They also use hi freq pulsers, meant for lead acid batteries, so that the crystaline structure is much finer than a new battery (that creates more surface space per battery, and more juice).
All of this excessive activity is harsh on NiCads, shortening it's overall total amount of cycles. These batteries never die from "memory loss", but are flat worn out.
Me...I'm just happy to occasionally pulse the 18 volt NiCad battery in my portable drill for odds and ends.
Unlike a lead acid battery, never trickle charge a NiCad...It eventually kills it. I know some applications are made to normally keep them trickled, like a UPS power back up, or a NiCad Flashlight hooked up to a wallwart. Disconnect them occasionally, and let them run down a bit. Better yet, just use them. NiCads live longer when exercised...Lead Acids like to live in suspended animation, while being trickle charged.
NiCads like to be fast charged, Lead acids slow.
Handling, charging and using NiCads is almost the opposite of Lead Acid batteries.
Don in Tulsa
----- Original Message -----
From: Dan Batchelor
Sent: Friday, April 28, 2006 5:29 PM
Subject: Re: [Aquarius-owners] Re: pulser desulfater
Thanks very much for your posts. Not only did I order a pulser, but I have ordered a 100 amp load tester and a few float chargers. I plan on having a 2 or three battery bank and want to keep them in top shape. Your info should prove invaluable as I embark upon keeping my batteries in tiptop condition......for many years!
C22 Swing Keel
Beachwood, NJ (Barnegat Bay)
----- Original Message -----
From: Donald Plisco
To: Dan Batchelor
Cc: awea ; email@example.com ; firstname.lastname@example.org ; email@example.com ; firstname.lastname@example.org ; Coastal-Recreation-Inc@yahoogroups.com
Sent: Sunday, April 23, 2006 1:21 PM
Subject: [Aquarius-owners] Re: pulser desulfater
Some PIC controlled and other types don't spark much when hooked up. The computer chip ramps up the current later. Others, give a shower of hi frequency sparks on the Positive post...Those sparks could light up the hydrogen gas coming out of a vent cap from a freshly charged wet cell, so don't entertain yourself with this amusement often. Hook up the positive post FIRST, then hook the neg post up. Very little sparks come from the negative post. Pull the negative lead first, then the pos. This reduces sparks. When jump starting a car, use the same regimen to reduce sparking with the jumper leads. Always hook the positive lead to the positive post first. When you connect a clamp or lead up to the first battery post, there is no juice flowing thru it. When you connect the second lead, that is when the sparks fly.
Higher indicated voltage generally indicated a lack of conductance. The pulsed voltage will decrease as the sulfates are removed, and conductance increases. Remember, this is all relative...No batteries are exactly alike. The Midtronics Midtron analog conductance tester that I have, will read out the exact conductance (unlike most of the go/no-go digital conductance meters that are made for clueless dolts). Two brand new batteries may read alike, but after a couple of months service, they will never read the same.
Dan, remember this: An otherwise good, but badly sulfated battery, is very much like a shrunk battery. The surface of the plates have been covered with hard sulfate crystals, which inhibit the electrochemical activity of the plates.
Since there is less free surface, it will accept less charging current. Forcing more current only forms heat, since the energy cannot be absorbed into the plates. Overheating a battery kills it, or at the very least, cuts down on it's life.
Since the plate surface is reduced, the battery will quickly charge up (just like a smaller battery) on the same current. If it is not shorted out from a broken plastic separator, debris touch the bottom of the plates, or "Mossing" (sulfate dendrites), it will hold its charge. But it is a small charge, since ther is very little free surface. In a car, this means the starter will turn over quickly at first, then poop out after a few seconds. If your engine is well tuned, you'll never know your battery is sulfated until one cold winter evening, out in the middle of nowhere....
I'm half deaf from noise induced hearing loss, so I can't hear a pulser until I almost stick it against my ear. Younger people can hear them across the room. The AM radio trick always works. Try it when you have a half dozen pulsers running at once...it's a melody, or worse.
"Hot" discharging is throwing a very heavy discharge across the posts (just short of melting them) for a few seconds. It deplates the free lead metal off of the surface of mossing, and everything else. "Mossing" is a phenoma of deep cycle slow charging and discharging. You generally won't find it in Auto batteries, since the act of starting and hard alternator charging keeps them under control.
Sulfates will form dendrites that look like moss or roots, that cross over the plates or thru broken plastic separator plates. Sulfate crystals don't conduct, but they (and the plates themselves) get plated with free metal from the slow charging. The is the same process as electoplating silver, gold, chrome or nickel over base metals.
Once plated with metal, the dendrites form shorts between the plates. Hot discharging deplates the metal off and pops the dendrites loose. Pulsing dissolves them.
Another phenomena that I have noticed from pulsing heavily sulfated batteries is that in the process of trickle charging or slow charging the plates back up, new shorts will occur when the voltage reaches about 12.75 to 13 volts. I believe this is caused by excessive free metal being released by the pulsing, and the plating effect of the slow charging. Most pulsing induced shorts will develope into harder shorts that cannot be removed, if left alone. Hot discharging can pop these new shorts loose if you catch it early.
I always notice that after hot discharging, the conductance and ability to supply a current will increase (even though the surface charge is removed). Others have noticed this too. Don Denhardt first brought this to my attention when using a 100 amp load tester.
How to hot discharge: if nothing else, use a heavy tire iron. Iron is a poor conductor and forms an excellent resistor that will limit the heavy current. The heavy piece of metal will not immmediately heat up when shorting the terminals and burn your hands.
NOTE: Never short the terminals with a copper cable! Too much current will flow, overheating the cable, burning your hands, and possible exploding the battery from too much heat or igniting the hydrogen gas.
Simply take the tire iron and short the terminals for several seconds. I've done it thousands of times...Literally. It won't overheat the iron...I use bare hands when doing this, so that I can sense the heat. The only problem with this is that the arcing from the connect/disconnect can melt part of the lead terminals off. To prevent this, make the connection fast and break it quickly. This will limit the arcing. Another note: If you short steel terminal parts (a steel nut or bolt) a spot weld will occur. Don't panic...Just give it a sharp and hard twisting snap and the light weld will break...Always.
Load testers will also hot discharge a battery to a degree. Even though the load tester has copper cables on the leads, it has a load resistance inside of the tester (made of steel sheet or wire).You can see this glow red if you leave the load tester on for too long. Don't do it...it overheats the electronics in the tester. Let it cool down between tests.
Even though I have all sorts of fixed value load testers, I prefer my 0-500 amp carbon pile, variable load tester.
500 amps is probably more than a tire iron can carry. Not only can I load test the battery with a lower load, but I can turn that puppy up for a few seconds and play havoc with mossing. I changed out the 4 AWG leads on the Harbor Freight tester for 2 AWG (I noticed they got uncomfortably hot after a couple of tests). I changed the internal wires (14-18 ga) for 10 AWG. I cut an 80mm hole in the case and installed an 12 volt 80mm computer case fan, and opened up the louvers on the case with a needle nose pliers. As long as the leads are hooked to the case, the fan cools the internals down. I can run more than the three factory recommended tests in a five minute period.
If nothing else, use a tire iron for a few seconds to no more than ten seconds, to get a good surface deplate.. Repeat it three times, then charge and/or pulse. Don't be timid about it, it won't bite.
Don in Tulsa
----- Original Message -----
From: Dan Batchelor
To: Donald Plisco
Sent: Sunday, April 23, 2006 8:34 AM
Subject: Re: pulser desulfater
I am trying to desulfate a deep cycle 75 ah 12volt battery.
Ah....very clear now. I also went back and did some more reading on some links on the courtiestown website. Now I understand. Now for another question. (I hope you don't mind) I purchased the high power pulser with Peak voltage detector connections. My VOM reads 104 volts connected to the Peak Voltage detector. Does this indicate a badly sulfated battery? If so, this voltage reading will drop daily, correct?
Yes, I can hear a high pitch tone coming from the pulser, but only when I put my ear to it. I turned on an AM radio and hear it humming. But I was disappointed because there was no sparking when I hooked it up. Shouldn't there be sparks?
One more question. What is "hot discharge"?
Thank you very much for all your help. The learning curve here is a bit steep.
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