Corrosion.....again

[Solze1267 202]

Problem is.....had an old battery on my 1267 and the positive terminal corroded really bad to the point I had to replace the wires that came off of it and put a new battery in it......that was 3 weeks ago. Fast forward to yesterday, I went out to start it to plow the garden under and noticed the trickle charger I keep on it was blinking (not charging). Looked at the battery and the positive terminal is again fully corroded and actually ate through the lead for the charger. At that point frustration set in....luckily it started and I used garden plowing as therapy to calm down. I have no idea why or how with all new leads it corroded that fast. The tractor is kept inside my garage out of elements. Guess I just don’t understand how things could go bad that quick when I have older batteries that have zero corrosion on them. Let me know what you think

[squonk 38,844]

How old is this battery and what kind of charger do you have? 

[Solze1267 202]

@squonk the battery was purchased a month ago for a different tractor but never got installed in it(not sure how long It may have set in the store) and the battery tender is a “battery tender jr” the ones with the green labels and it was brand new also

[squonk 38,844]

Swap the battery with one from another tractor. See if the corrosion goes along with it. Could be a tiny leak in the battery case

 

[953 nut 51,511]

coating the terminal and connectors with some dielectric grease should do the trick, any brand is fine.

[Solze1267 202]

I grabbed a can of the Electrical insulating varnish from work the other day and will pick up a new battery to see what happens. Fingers crossed it fixes the issue since even though it isn’t my daily mower it’s my “work” tractor I depend on

[lynnmor 6,762]

Have the battery tested after fully charging it with a larger charger.  Check the voltage while connected to your trickle charger to see if it stays on high output.

[bc.gold 3,399]

During the charge cycle the lead acid battery produces hydrogen sulphide gas, heavier than air with an affinity for metal. Even those maintenance free battery's are vented to discharge gas when an internal pressure of 2 to 3 pis is reached,

 

A marine style battery enclosure with a vent hose long enough to release the gas well below the tractor will at least inhibit some of the hydrogen corrosion attacking your tractor.

 

.Hydrogen sulfide is a chemical compound with the formula H 2 S, and is often a colorless gas with a rotten egg odor, commonly referred to as "sewer gas." H 2 S is:. Heavier than air; Very poisonous; Corrosive; Flammable; Explosive; Corrosion of metal and concrete is a major issue associated with the generation and oxidation of hydrogen sulfide.

 

Hydrogen Sulfide Corrosion

Posted on June 26, 2014 by Total Materia

 

Hydrogen sulfide corrosion and its prevention is an important topic in a range of industrial processes and environments including oil and gas and its related activities.

 

Mild steel is a popular structural steel in this industry but is susceptible to surface scale formation and associated corrosive action, the prevention of which requires some special methods.

 

The corrosion of steel in sulfide-containing solutions has received considerable attention for many years due to its importance in several industrial processes such as oil and gas production and transport. The evaluation of steel corrosion in sulfide environments is important in the petrochemical industry, as this phenomenon is responsible for costly economic and human loss.

 

Mild steel is a well-known structured material in the petroleum industry due to its low cost, good mechanical and corrosion resistant properties. The presence of some pollutants, mainly sulfide, in the oil itself can affect the performance of mild steel in the petrochemical industry.

 

Corrosion due to H2S is mainly electrochemical in nature. The products of dissociation of the H2S gas are aggressive and can catalyze electrochemical reactions, especially the dissolution of Fe.

 

Surface scale formation is one of the important factors governing the corrosion rate. The scale growth depends primarily on the kinetics of scale formation. In contrast to relatively straight forward iron carbonate precipitation in pure CO2 corrosion, in an H2S environment many types of iron sulfide may form such as amorphous ferrous sulfide, mackinawite, cubic ferrous sulfide, smythite, greigte, pyrrhotite, troilite and pyrite, among which mackinawite is considered to form first on the steel surface by a direct surface reaction.

 

The poorly known mechanism of H2S corrosion makes it difficult to quantify the kinetics of iron sulfide scale formation. A probable mechanism for iron dissolution in aqueous solutions containing H2S based on the formation of mackinawite film, as proposed by Sun et al. is shown in Figure 1.

Figure 1: Proposed mechanism of H2S corrosion on Fe

Figure 2: Signs of hydrogen sulfide corrosion include shallow round pits with etched bottoms

Methods of Hydrogen Sulfide Corrosion Prevention

 

1. Cathodic Protection – A technique used to reduce corrosion by making the material act as a cathode, while having a second material in direct contact that is more easily oxidized, which acts as the anode and the site of corrosion. For example, this means that the second material like zinc, will undergo the majority of the corrosion rather than the subject material which is then preserved such as the iron pipe line.

 

2. Galvanization – A process in which two different metals or metal alloys are placed in the same electrolyte fluid. The metal or metal alloy that has less corrosion potential typically coats the material that is to be protected and acts as an anode by polarizing itself toward a higher potential (positive shift); while the metal or metal alloy that has more corrosion potential acts as a cathode by polarizing itself toward a lower potential (negative shift).

 

This means that the material with less corrosion potential will experience corrosion at a much faster rate than the material with more corrosion potential. Galvanization is a localized form of cathodic protection where the strongest reducing agent acts as a sacrificial anode.

 

3. Chemical Inhibitors – One of the most effective methods of hydrogen sulfide prevention by adding a chemical inhibitor such as Catamin AB into the fluid. In a high concentration of hydrogen sulphide, an iron sulfide layer coats the material where the Catamin AB is adsorbed stably to. Catamin AB has vertically aligned molecules that is similar to the monomolecular film, which prevents the steel piping from dissolution and sulfide film growth.

 

 

 

Edited October 26, 2020 by bcgold

[bc.gold 3,399]

3 hours ago, Solze1267 said:

Problem is.....had an old battery on my 1267 and the positive terminal corroded really bad to the point I had to replace the wires that came off of it and put a new battery in it......that was 3 weeks ago. Fast forward to yesterday, I went out to start it to plow the garden under and noticed the trickle charger I keep on it was blinking (not charging). Looked at the battery and the positive terminal is again fully corroded and actually ate through the lead for the charger. At that point frustration set in....luckily it started and I used garden plowing as therapy to calm down. I have no idea why or how with all new leads it corroded that fast. The tractor is kept inside my garage out of elements. Guess I just don’t understand how things could go bad that quick when I have older batteries that have zero corrosion on them. Let me know what you think

 

Disconnect the cable at the positive terminal before recharging, your regulator probably has a leaking diode.

 

 

Edited October 26, 2020 by bcgold

[Solze1267 202]

@bcgold are you talking the voltage regulator for the tractor or something to do with the charger? Sorry electrical isn’t my strong suit...now if you want something painted I’m all over that!!

[bc.gold 3,399]

5 hours ago, Solze1267 said:

@bcgold are you talking the voltage regulator for the tractor or something to do with the charger? Sorry electrical isn’t my strong suit...now if you want something painted I’m all over that!!

 

The alternator on the tractor generates 3 phase ac current, if you were to look at that voltage on a oscilloscope you would see the sine wave. North American house current is 60 cycles per second.

 

Diodes are one way valves either positive or negative for instance a positive diode will only pass the positive side of the sine wave giving DC current.

 

Three phase produces 3 legs of usable power, usually defined as L1, L2 and L3, the alternator charging the battery would have 3 positive and 3 negative diodes.

 

One of the most common failures is when a person mistakenly connects jumper cables to the wrong battery terminals, the fully charged battery supplying the jump has enough power to blow a diode.

 

Being that diodes are electronic devices they are subject to cycle depreciation - old age.

 

How Does A Rectifier Work?

Updated on: 21 Oct 2019 by Akash Peshin

 

To begin with, your most prized possession would be unable to function without a rectifier: no, it’s not your phone, but its charger. Your phone charger and, for that matter, the majority of your household electronic devices do not operate on an AC supply – the alternating current generated by power plants and then supplied to your house via transmission cables — but rather on a DC supply: a constant current that flows unfailingly in a single direction.

The rectifier is a circuit embedded in your device that converts the restless AC supply coming to your house into a steady DC supply, so that your devices can function properly. However, how does the rectifier achieve this rectification?

The Diode

The diode is one of the semiconductor revolution’s first offspring. The device is basically two slabs of semiconductors glued to each other. However, the semiconductors differ in their properties: one is electron-impoverished, or exhibits an excess of positive charges or holes, while the other is suffused with electrons and therefore exhibits an excess of negative charges. Together, they constitute what is called a PN Junction.

The fundamental purpose of a diode, unlike a resistor, is to allow current to flow in a single direction. Current through a diode will only flow when its positive semiconductor, or the anode, is connected to the positive terminal of the battery, and its negative semiconductor, or the cathode, is connected to the negative terminal of the battery. The current is stifled when the terminals are cross-connected.

The diode lies at the heart of the rectifier, where the rectifier leverages its properties to fulfill its purpose.

Rectification

First of all, the AC voltage is drastically reduced, as a triple-digit voltage will fry your toaster or charger. This is achieved with a transformer or a voltage regulator. The diminished AC supply is then fed to the device, where it is first greeted by the rectifier. The rectifier converts the AC to DC and then passes it to the device’s core circuit.

A rectifier can generate a DC supply either by rectifying only one cycle (either positive or negative) of the AC supply or by rectifying both of them. The former is therefore called a half-wave rectifier, as it only rectifies one half of the supply waveform, while the latter is called a full-wave rectifier, as it rectifies both halves or the entirety of the waveform.

Half Wave Rectifier

The magnitude of the AC supply is reduced with a transformer and fed to this particular configuration of diodes. The configuration will rectify only the positive cycles of the waveform:

Positive Half-Wave Rectifier

During a positive cycle, a positive charge is obtained on the upper node, while a negative charge is obtained on the lower node. Now, because a diode will allow the current to pass only when the anode (the triangle) is connected to the positive terminal and the cathode (the stick) is connected to the negative terminal, both the diodes in the configuration will conduct during the positive cycle. The load is therefore supplied with a current: the positive cycle is replicated on its output waveform.

However, when the AC supply alternates, the polarity on the nodes swap: now, the upper node is negatively charged, while the lower node is positively charged. The diodes are cross-connected and the current ceases to flow. When no current reaches the load, the output waveform for the negative cycle is a line tracing the X-axis, depicting the passage of time, but not any current.

 

Voltage Across The Load After Rectification

The negative cycle can be rectified (at the cost of the positive cycle, of course) through some tinkering with the configuration of the diodes:

Negative Half-Wave Rectifier

The configuration is such that the load will experience a current during the negative cycle, more specifically, when a negative charge is obtained on the upper node and a positive charge is obtained on the lower node. Of course, being a half-wave rectifier, the current is stifled when the current alternates and the polarities swap. As this rectifier only rectifies the negative cycles, its output waveform will look like this:

Voltage Across The Load After Rectification

However, one can observe how the waveforms are bumpy: two waves of productivity separated by an undesirable void of idleness or unproductivity. The waveform can be “smoothed” with a large, filtering capacitor. The capacitor will accumulate energy during the productive cycle and release it during the unproductive cycle until the next productive cycle begins. It then reaccumulates energy and the whole cycle repeats. The result is a bridging of the valley – a constant, unidirectional DC supply.

Still, the conversion is dramatically inefficient: why must we waste half of all the energy? Why shouldn’t we utilize every ounce of it?

Full Wave Rectifier

One rectifier rectifies only the positive halves, while another rectifies only the negative halves. So how do we develop a rectifier that rectifies both halves sequentially? Simply by combining the two rectifiers!

Full Wave Rectifier

The circuit appears enmeshed and therefore automatically complex and confusing. However, its function, on the contrary, is astonishingly simple. Examine the circuit carefully and you’ll observe that it is literally a combination of the two half-wave rectifiers explained above.

The first half-wave rectifier conducts during the positive cycle, while the second half-wave rectifier conducts during the negative cycle. As the current passes through the load during both cycles, no voids are found in the output waveform. It is a continuous series of hills, or trail of energy.

Of course, gaps do exist between the hills, but they are much narrower than the gaps in the output waveform of a half-wave rectifier. We can remove these small inconsistencies, again, with a large filtering capacitor. The smoothed waveform is an even steadier, energy-efficient and high-quality DC supply.