Lithium Batteries – Show Some Respect

April 27th, 2013

They’re showing up everywhere. They’re in our phones, our electric razors, laptops, portable power drills, Bluetooths, some electric cars and now they’re beginning to appear in boats. But, you say “what’s the big deal? A battery is a battery.”

But these batteries are different.

A while back I posted an article on the Tri-State Marine web site’s BLOG page, addressing the different kinds of batteries we commonly deal with in our everyday life. (It’s still there. Check it out.) Now, more recently, I have been hearing more and more about Lithium-Ion batteries. There was a passenger air liner fire a few months ago, related to one of these batteries. And a recent conference I attended, devoted a 2 hour segment to discuss and inform us of the pros and cons of this new technology. Yes, I said new, although the first discoveries and work began some 40 years ago. The research and improvements are on-going, and we should expect to see more change in the future.

The “flooded-cell” technology dates back to the mid-1800’s. These are the Lead-Acid batteries we are all familiar with in our autos, boats, golf carts, etc. We all remember the car batteries with little caps, where the gas station attendant looked to see if there was enough water/acid in the cells. (Guess I’m showing my age. What’s a gas station attendant?) But now, even though the little caps are gone, the batteries are still referred to a flooded cell.

“Dry cell” batteries are like the throw-away flashlight batteries we are all familiar with. These are not rechargeable and simply work until they die, and we throw them away.

It’s interesting to step back and analyze the development of batteries. In the early 1900’s the automobile industry drove battery technology to develop portable and rechargeable batteries for the cars. And today, it’s the automobile industry emerging again as the driving force to develop Lithium-Ion batteries for the electric car market.

So you ask: Why Lithium Ion ?

There are several desirable advantages to this new technology:
1) Higher Energy Density – Lithium batteries produce more energy, pound-for-pound than other technologies, and take up less space; 1/3 -to- ½ the weight of conventional technology. For a given volume of allocated space in your laptop, the Lithium-Ion battery delivers up to twice the power of older technologies.

2) Flat Output – The voltage output of a Lithium Ion battery remains relatively constant, right up until it goes dead. In other (older) technologies such as NiCad for example, tend to put out lower and lower voltage as the battery runs down.

3) Lithium Ion batteries re-charge faster.

4) Lithium -Ion batteries live a longer useful life. – On average, typical flooded-cell battery will live through approximately 500 charge and discharge cycles, before needing replacement, while a Lithium battery will live 4 -to- 10 times longer.

So what’s the big deal? Why aren’t we all moving to the newer technology of Lithium Ion?

In a nutshell: They’re more expensive and if not handled properly, they can be dangerous. Lithium in metal form is dangerous. When mixed with water, it combines violently to produce highly flammable Hydrogen gas and corrosive fumes of Lithium Hydroxide. Additionally, if Lithium is heated, it releases toxic fumes and can cause violent combustion and/or explosion. Lithium also reacts violently with strong oxidants, acids, and compounds such as hydrocarbons, halogens, concrete, sand and asbestos, causing fire and an explosion hazard.

But they’re working on it. The battery industry has made good progress in this arena, from the safety aspect. And, as the technology develops and more batteries are produced, we can expect to see the price drop.

Battery Operation: What makes a battery work?

Batteries are basically a chemical reaction between two dissimilar metals when both are submerged in an electrolyte. (An electrolyte is a solution which will conduct electricity.) This process is also known as “Galvanic Corrosion” when used in some other discussions. It is a flow of electrons which are stored on the negative plate (Anode) through the electrolyte, to the positive plate (Cathode).

The voltage produced is dependent on the materials used. In the case of our familiar lead acid battery, we generally see a voltage of 2.1 volts from a battery cell. But when Lithium is used in the construction, the voltage rises to a nominal 3.4 volts. Therefore, we get more output from the same weight and volume.

Batteries of 2 or 3 volts are not capable of performing much work. So, we get around this by connecting them together. If we combine 6 of the flooded cell type batteries at 2.1 volts each in a series connection, we get a battery “pack” of 12.6 volts. This is why we used to see six little caps atop the car battery. But if we combine only 4 of the Lithium Ion cells at 3.4 volts, in series, we get a battery pack of 13.6 volts; more energy…less space. The voltage difference is due to the difference in materials used in construction. The voltage remains consistent. However we can increase the amount of power (amperage) available from the battery, by connecting cells, or packs) in a parallel connection. By doing so, we increase the power of the battery, or amp/hour life span, before it needs to be re-charged. Think of electricity as water through a pipe. Voltage is analogous to water pressure, and amperage is the amount of water flowing.

Charging and Discharging a battery:

A rechargeable battery has a voltage level whereby it is considered to be fully charged and another level whereby it is considered discharged; or at a voltage which is too low to perform the duty for which is has been designed. Charging a battery higher than it’s designed maximum, or discharging below the designed minimum is not good for the battery and can be dangerous.

Over the past century, nobody has paid too much attention to battery chargers. Local gas stations and back yard mechanics would simply hook them to a battery and let them cook for a while, to recharge a battery. The choice was usually 6 or 12 volts. For the most part, in the non-military and non-industrial world, all other batteries were “throw-aways“ whereby salvage folks would usually reclaim the lead metal. But then came the battery revolution which brought about rechargeable. Dominating the consumer rechargeable market for the most part was the nickel cadmium (NiCad), and nickel metal hydride (NiMh) battery. They are still available and still in use today. Chargers were available for them and most of us still didn’t pay too much attention to which charger we used. (Although we knew there was rumored to be some sort of difference in them.)

Running a wet cell (flooded cell) battery down past it’s designed “discharged” point will shorten the battery life, and over-charging it will also warp the plates and shorten life. But other dangers such as fires or explosions are not real common. And the same holds true with NiCads.

When recharging a Lithium Ion battery however, we must be more careful. Over charging a Lithium battery will cause it to create it’s own internal heat. The heat created will cause the Lithium to create more internal heat, and a possible “runaway” condition begins, which can lead to a fire and/or explosion. Conversely, if we discharge a Lithium Ion battery below it’s designed discharged point, it begins to heat, which can also lead to a run away condition. Therefore, using the proper charger is imperative. The charger must recharge at the proper design voltage and stop charging at the designed point.

Additionally, when Lithium Ion batteries are installed in a product, and are in use, they must be monitored and managed to ensure each cell is not being drained too low, and/or developing too much heat. Battery Management Systems (BMS) are designed into all products, using Lithium batteries.

Care of a Lithium battery:

The workhorse of the consumer batteries is the small “penlight” style this little battery cell is known as the 18650 size. It’s 18mm in diameter and 650mm long. It produces approximately 3.4 volts and is generally used in battery packs in series/parallel combinations to make up the desired voltage for the need. Lithium batteries do not have set standards as of yet. They basically come in cylindrical shapes such as the 18650, and larger, or soft packs, or hard box-like cases of various sizes.

Due to the nature of Lithium batteries, they must be cared for to guard against puncture, and extreme temperatures. Puncture can cause internal short-circuiting which leads to heat. Heat leads to more heat and melting of insulators and more short circuiting, and on and on……. This is a major concern for automotive use, and packing for shipment.

When exposed to high temperatures in the range of 176 degrees Fahrenheit for a couple of days, Lithium will begin self-heating, internally. The self heating will continue toward a runaway condition. Break down of internal components of the cell begin in the 167 -to- 194 degree Fahrenheit range. And so it begins: Internal shorting creates more heat. More heat breaks down more insulators, creating more internal shorting, which creates more heat. More heat causes the Lithium to release more heat of it‘s own.…………. And so on.

But wait…… There is some good news too:

Laboratories are working as we speak on a variety of materials to make a safer battery. Typically, Lithium is not used in the metal form. Pastes containing Lithium are used to coat plates of aluminum and copper, or graphite. (materials vary) Obviously, the electrolyte is not the conventional distilled water we have been used to. Rather they are using a variety of electrolyte mixtures, which are typically composed of organic carbonates. Each manufacturer varies the electrolyte to his own “proprietary” mix to meet the needs of the product. For example, viscosities may vary to meet the anticipated environmental temperatures of the product use, etc.

Lithium batteries are becoming more safe by the day, and the cost is and will most likely continue to come down. Batteries are in our future.

The message I pass to you is to respect this new technology. It is indeed new. If you have an installation of Lithium batteries in a car or boat, be sure to label the product as such, in case the fire department is called to assist. Adding water to one of these fires is a No- No.

SWIMMING IN GARBAGE

September 13th, 2012

If your boat is 26’ or larger, then you should have a placard displayed aboard, setting standards of what and where we are permitted to dump into the sea.  (If you don’t have one, call me.) This placard is required by the USCG (US Coast Guard, as stated in CFR 33  151).    But, effective January 1, 2013, the rules are expected to change.

The initial standards of discharging unwanted items into the sea were set by an international group called IMO (International Maritime Org.)  In 1973 the group formed to set standards to prevent ships from polluting the seas.   The group met again in 1978 and published a document called MARPOL 73/78, which is followed by the USCG and affects us, right here on our own lakes and rivers.

The current MARPOL 73/78 allows for some discharge of garbage and sewage, depending on the vessel’s distance from nearest body of land.  Nobody is ever allowed to dump plastics, or synthetic nets, ropes etc.  into the sea, according to the standards.  (CFR 33 151.67)  But, the seas continue to become more and more polluted, as has been proven by findings of studies which measure the amount of garbage and debris which washes ashore.

 

SO…… WHAT’S THE BIG DEAL ?

First, we’ll start with a little physics lesson:

From a global perspective, the oceans of the world have a natural current flow.  Oceanographers refer to these currents as “gyres”  (pronounced jeers) and have determined they are caused from a phenomenon known as the “coreolis” effect

Coreolis effect is a deflection of moving objects when viewed from a rotating reference frame.  Perhaps the most commonly encountered rotating reference frame is the rotation of the earth, and the water in the oceans.  The rotating force causes moving objects (ocean water) to veer to the right, with respect to the direction of travel in the Northern Hemisphere, and to the left in the Southern Hemisphere.  This effect sets up a rotating current, or vortex, in large bodies of water.  The current travels, forming a circular flow; clockwise in the Northern Hemisphere and counter-clockwise in the Southern Hemisphere.  One of the more familiar examples of this current flow is the “Gulf Stream” which flows from Florida, toward Maine, along USA’s east coast.

 

 

 

There are many of these gyres in the large bodies of water of the world.  There are five however, which are much more dominant, located in:  1) North Atlantic, 2) South Atlantic,  3) North Pacific, 4) South Pacific, and 5) Indian Ocean.  The circular flow tends to cause a swirl at the center, similar to the water in a toilet when it is flushed, but much slower and more subtle.  The centers of these gyres tend to collect debris, which becomes trapped in the circular flow and cannot escape.

A patch of this debris located in the North Atlantic Ocean, was discovered in 1972.  It is over 990 miles in length (22 degrees N-Lat – 38 degrees N-Lat) and unknown in width.  The patch tends to seasonally drift about, and is roughly located between Cuba and Virginia, hundreds of miles off the East Coast  of USA.  An estimation of pollution has been made at :  200,000 pieces of debris per square kilometer.

In 1988, NOAA (National Oceanic and Atmospheric Administration) predicted there would also be a garbage patch in the Northern Pacific Ocean, but had never located it.  Then in 1997, a sailor named Charles Moore came upon an enormous field of floating debris, centrally located in the Pacific of the Northern Hemisphere.   The patch has become known as the “Great Pacific Garbage Patch”.   It is the size of Texas, and contains roughly 3.5 million tons of rubbish, consisting of old fishing nets, plastic bottles and plastic items of all descriptions, including plastic ice cream tubs and polystyrene.

In years past, it was generally believed that the oceans would simply absorb anything that was thrown into them.  But now, we are discovering where all that stuff went !   Plastics can circulate in these patches for years and years; some have estimated nearly 450 years, before they completely deteriorate.  But, it’s not all on the surface.

Researchers in Japan have studied ocean samples and discovered derivatives of “polystyrene” a common plastic which is used in disposable cutlery, Styrofoam and DVDs, among other things.  These toxic compounds are not naturally found in the oceans and are believed to have been inserted by partial deterioration of plastic items.  The deteriorating plastic pollution tends to suspend in the water, forming a” toxic soup” which can extend to as much as 60’deep in the water column.  Suspended particulates in the “soup” get consumed by creatures living in the sea.

 


 

 

SO…….    WHY DO WE CARE ?

A major (and selfish) reason for concern is preservation of our food chain.  Small creatures eating toxic waste become consumed by larger creatures, who in turn get eaten by larger  creatures……. Etc……Etc.     At the top of the chain is a human.  And, by this time, the food source contains a high concentration of toxicity.    Okay, now, I’m getting interested in all this stuff !

BUT, THERE’S BAD NEWS.

NOBODY has the resources to clean it up.  So, there it sits.  All that “stuff” just swirling around out there.   And there’s more:

Remember the Tsunami that hit Japan in March of 2011 ?   There’s a LARGE field of debris, spread over thousands of miles of ocean, from the back wash of the tidal wave.  The debris consists of a wide variety of items ranging from boats to footballs, and is currently located somewhere north of Hawaii near the Midway Atoll.  The debris being carried by the North Atlantic gyre, and is expected to begin washing ashore on the West Coast of USA in late 2012, and continue through 2013.  The good news is that experts predict ocean currents will prevent 95% of the debris from actually landing ashore.  Rather, they predict, ocean currents will cause it to simply pass by, eventually joining up with the “Great Pacific Garbage Patch”.

WHEN YOU FIND YOURSELF IN A HOLE………STOP DIGGING !

Thus we have come full circle.  MARPOL has written an amendment to Annex V (the one that deals with garbage pollution) which is expected to go into effect January 1st, 2013.  Which basically says:    Don’t throw anything overboard.   Take it back to port, for disposal.

Happy Boating !

 

Ron Smith

Principal Surveyor For:

Tri-State Marine Services, Inc.

Electrolysis……. What’s That ?

September 11th, 2012

 

 

It’s a term that’s widely misused.    Many times as boaters, we hear (and use) the word electrolysis.  But what is it……. Really ?

In the marine world, we are used to speaking about corrosion and/or decomposition of the underwater metal components of our vessels as suffering from electrolysis.  If we better understand what is happening, then we can help prevent (or reduce) the costly destruction.

Let’s start by understanding the players.    In the case of our family boat,  we have a metal component, submerged in water.  (Sometimes we have a shore power cord in the picture as well, which we will talk about later.)  Also, there are two different types of  corrosion.  They are termed “GALVANIC” and “ELECTROLYTIC”.

Elements of the periodic table can be classified as metallic, or non-metallic, for a variety of characteristics.  Two of those characteristics we are particularly concerned with in this discussion are:

1)  Metals generally have 1-to-3 electrons in their outer shell, where non-metallic have 4 or more.

2)  Metallic elements tend to lose electrons in their outer ring more easily.

We also know that when the common metals we deal with in boating are  submerged into an electrolyte* (water), they will begin losing protons to the solution, leaving behind electrons, which give the submerged metal a negative electrical charge  This negative charge can be measured in millivolts

(1/1000).

* An electrolyte is any solution which can conduct electricity.

Now, if  a second dissimilar metal is introduced into the same solution, and there is an electrical connection between the two metals, we will begin seeing a flow of electrons through the electrolyte, whereby one metal will erode more rapidly than the other, as the two metals attempt to “balance” their electrical charges.   This phenomenon is known as “GALVANIC CORROSION”.  It’s worth mentioning, that an electrical connection can be accomplished by mounting (or attaching) two components together, without the use of wire.

Electricity is defined as the “Flow of Electrons”.

All metals have a different molecular structure, thus giving them different “base” electrical potentials.  The pecking order of these charges are listed from least -to- most negatively charged on a “Nobility” scale.  The most negative charge, or least noble, erodes more rapidly.

One method to reduce the amount of  galvanic corrosion is to ensure each component is  electrically connected or “bonded” to the others, and install sacrificial anodes into the bonded network.  The sacrificial anodes, commonly referred to as “zincs” will become the least “noble” metal and will thus sacrifice themselves, and preserve the more valuable components of the boat.

A second method of preserving the valued components is to “impress” a current, or electrical charge onto the bonded network.  There are several manufacturers of these “impressed charge” systems on the market today.  Many of the sterndrive manufacturers protect their drive units with these devices.  In doing so, they are primarily concerned with protection of their own unit, and not the whole boat. Therefore, they wish to remain isolated from the bonding  system, so you sometimes will see a border of un-painted area about an inch wide around the mounting point of the drive, to the hull.  This is done because many bottom paints will conduct electricity, and thus become the bond connection to all other through hulls on the boat.

But, what about that pesky shore power cord I mentioned earlier?  This brings another aspect into the picture, called “ELECTROLYTIC CORROSION”.  This occurs when an outside electrical connection is introduced into the vessel.  A malfunction on our boat, or even a neighbor in the harbor could find an electrical path to earth ground, through the shore power cord’s green wire ground.  This DC (Direct Current) could provide an easy path for electron flow, which is capable of rapidly increasing the galvanic process.

Any boat with a shore power connection will benefit from a galvanic isolator.  The objective is to eliminate the possibility of DC current flow of corrosion from flowing to earth ground, via the green wire of the shore power cord.   Galvanic isolators are installed in the green wire of the shore power connection, and through a network of diodes and capacitors, will eliminate DC flow through the shore power cord.

This has been a ten thousand foot overview of a subject which can (and does) fill volumes of literature.

If you are experiencing a corrosion problem with then look into it.   Help is available… call me.  A few tips for happy boating:

Corrosion surveys can save you money, by ensuring proper protection of the boat.

NEVER SWIM IN A HARBOR.  Stray currents from ANY boat can be very dangerous, and YOU could become the electrical connection to “earth ground”.

And, oh yes:   ELECTROLYSIS is a widely misused term, which technically has no meaning in a marine context.  It refers to the degradation of an electrolyte that occurs as a  result of passing an electrical current through it.

 

Ron Smith

Principal Surveyor For:

Tri-State Marine Services, Inc.

12 Volt Batteries

September 11th, 2012

Have you ever wondered what all those terms and acronyms refer to when shopping for a new boat or RV battery?  Terms like Deep-Cycle,  CCA, MCA, Ah and Gel don’t mean a thing to many of us.  But, those terms do indeed have meaning, and they can have an effect on your pocketbook, and/or the lifespan of your new battery.

Generally speaking, there are three distinct types of batteries in use on today’s boats and Rvs;  Flooded Acid, Gel’d Acid and AGM (Absorbed Glass Mat).  And, (still speaking generally) these three types of batteries are divided into two categories:  Deep Cycle, and Starting.

A battery is a device which stores energy; stores it; not manufactures it, but stores.  It’s much the same as collecting rain water in a barrel for later use.  Batteries store this energy in the form of electricity, and are able to do so with a chemical reaction, using sulfuric acid as an electrolyte with lead plates.  The grids of lead plates (sometimes a lead alloy) are suspended in a grid within the battery case, whereby they are surrounded with the electrolyte.

The type of electrolyte will differentiate the three “types” of batteries, referred to earlier:

1) FLOODED ACID  batteries are the conventional “add-water” types we have grown up with in the family automobile.  We all remember opening the small plastic caps and checking the water (acid) level,  to ensure each cell was full to the indicator ring.  Most recently, batteries have been available without the little caps, and are now called “Maintenance Free”.

2) Then came GEL ACID batteries.  Gel batteries offer ease of maintenance, as the water (acid) inside has been thickened with silica gel, which turns it to a jelly. The jelly won’t  evaporate or spill; even if the outer battery case is cracked open.  These batteries quickly became popular in wheel chairs, Rvs and snowmobiles as the gel offered support to the fragile lead plates in areas of impact and vibration. Additionally, the inability to spill acid as in the flooded acid types, made them safer for travel.  A disadvantage of the gel battery is it cannot be “fast-charged”.  Therefore the battery charging equipment may have to be adjusted to the battery manufacturer’s specs. To avoid damaging the battery.

3) The newest lead acid type of battery is known as the AGM (Absorbed Glass Mat) type.  This technology offers all the advantages of the Gel battery, yet it does all things better, having no disadvantages when compared to the flooded acid types, other than cost.   (2 -to- 3 times that of the flooded acid)

A battery will self-discharge, due to internal resistance; even when not in use.  Flooded acid batteries will discharge at the rate of  approximately 1% each day.  Gel and AGM batteries (sometimes referred to as VRLAs*) will discharge at around 1% -to- 3% per month. * Valve-Regulated Lead Acid

Batteries also lose (or convert) some of the energy put into them into heat, while being recharged.  While a flooded acid battery will convert 15% – 20% into heat loss, a gel battery will lose only 10% – 16% to heat and the AGM will only lose around 4%.  Thus, your charging system can be smaller, or simply recharge faster.

“Starting” and “Deep Cycle”

Starting batteries are constructed to produce large amounts of current for short periods of time, for high amperage needs, such as starters and anchor windlass’.  Deep cycle batteries on the other hand, are designed to produce a smaller flow of current, over an extended period of time.

The DOD (depth of discharge) is a measurement of how much energy is removed from a fully charged battery.  Several factors will determine battery life.  A battery cycle is defined as bringing a battery from full charge, to DOD and then back to full charge.   A battery which is not routinely depleted to a deep DOD (say 50% DOD) will out-live one that was depleted 80% each cycle.  Other factors play into battery life as well, including ambient temperatures.  While operating in warmer temperatures provide a battery with more capacity, it also shortens the lifespan.

An interesting note:   A fully charged flooded acid battery will not freeze in winter temperatures; a dead battery will freeze.  Also, the VRLA batteries do not have to worry about freezing temperatures.

This brings out another advantage of the VRLA batteries:  They do no emit gases or water, during recharging.  They are termed “recombinant” – which means the hydrogen and oxygen re-combine inside the battery, with no outside emissions.  These batteries are suitable for installation areas where no ventilation is available, such as bilges, which are nice and cool.

So you ask:  What part of the construction makes it a “Deep Cycle versus Starting?”

It’s the lead plates.  A Starting battery will have many thin lead plates that appear sponge-like, creating a lot of surface area.  A  Deep cycle battery will have much thicker, solid, smoother surfaced (not sponge) plates inside.   A deep cycle battery is capable of  up to 80% discharge, although a better cycle would be 50% DOD on a continuous basis.  A starting battery is designed for a cycle of 2% -to- 5% DOD, and if taken to deep cycles on a routine basis, the thin sponge-like plates will quickly deteriorate.

The larger (sponge-like) surface area of the starting battery provides added area for chemical reaction, creating high current flow for starting.  While the thicker, solid plates of the deep cycle battery cannot produce the rapid, high current, they are built for the “long-run”, and are more durable.

Group Size is a description of the physical size of the battery case, and terminals.  It does not necessarily refer to the electrical capacity.

Terms used to describe Starting Batteries:

CCA and MCA refer to “Cold Cranking Amps” and “Marine Cranking Amps”  Each is a rating of current flow ability of the battery.  MCA is the same as CA “Cranking Amps”.    The difference is, CCA is measured at 0 degrees Fahrenheit, whereby MCA and CA are measured at 32 degrees Fahrenheit.

Deep Cycle batteries are described in terms of Amp Hours (Ah):

The ability to produce 1 amp of current for one hour = 1 Ah.  Or, 2 amps for ½ hour is 1Ah; 20 amps for 1 hr = 20Ah, and so on……..

Tid-Bits

When shopping for a battery, a good rule of thumb is the weight of the battery.  The heavier the battery, the more lead in the plates.  Lead plates deteriorate over time.  Therefore, more lead can relate to a longer battery life.

Keep your batteries charged, and cool.

Flooded Acid versus AGM  (Gel is less favorable when compared to AGM for similar money):  Flooded acid is 1/3 -to- ½ the cost of AGM or Gel.  Flooded acid is a “good fit” for the money, if ventilation and spills are not an issue.  But if the application allows, then “Flooded Acid” batteries are still widely used, as they can be more cost effective.

It is a myth:  Sitting a battery on a concrete floor will discharge it.

The deeper the cycles (DOD) of discharge;  The fewer cycles in the lifespan.

Don’t over-charge ( or “quick-charge”) gel batteries; it can cause permanent damage, by creating bubbles (voids) in the gel.

Can battery banks mix flooded cells batteries with gels and AGMs ?

Some say it’s okay.  But I don’t recommend it.  In fact, I’ll go one step further and recommend that all batteries within a bank are the same size, type and age.  The reason for this is to maintain equal charge/discharge rates among the partners.  Internal differences, create unwanted current flow between the individual batteries.  A battery’s electrical characteristics change with age.  Therefore, it is advantageous to use batteries of the same size, type and age within a single bank.  IE:  Don’t install a brand new replacement, into a bank of older batteries, if it can be avoided.

Ron Smith

Principal Surveyor For:

Tr-State Marine Services, Inc.