ALL ABOUT BIG BATTERIES

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ALL ABOUT BIG BATTERIES

• Batteries Use for Emergency or Field Power
  auto and marine batteries

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FIRST

• Batteries are not long term power supplies
• UNLESS
• There is a readily available way to recharge
  them.
• Generator
• Solar Panels
• Commercial Mains

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WHAT WE WILL COVER

• Chemistry of Batteries (how they work, so we
  understand the other parts of this)
• What kills batteries
• Different kinds of batteries (flooded cell, Gel
  cell, AGM)
• How to keep your battery healthy and prolong its
  life
• We will kill some wives tales along the way

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Lead Acid Batteries

• This presentation covers the following type of
  large batteries Lead Acid Batteries most
  often used by Hams
• Automotive cranking batteries
• Marine Batteries (also known as deep cycle or
  RV)
• Gel Cells
• AGM (Absorbed Glass Mat)
• They are big and heavy

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THE EXTREME BASICS

• Lead, lead oxide and sulfuric acid react to make
  electricity.
• There are plates of lead, plates of lead oxide
  and a solution of very strong sulfuric acid.
• These are housed in a plastic case with
  terminals on the outside.

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MAKING ELECTRICITY
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• Each plate generates about 1.02 volts, for a
  total of 2.04 volts
• Lead Sulphate is deposited on both plates.

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How To Get 12 Volts

• So we have a cell that makes 2.04 volts!
• Connect six cells in series
• Cells in series add their voltage
• 6 X 2.04 12.24 volts
• This is why a 12 volt battery will actually
  show a higher voltage than 12.
• That is why they are called batteries and not
  cells, they are a battery of cells.

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THE REACTION CAN BE REVERSED

• By applying a voltage to the terminals higher
  than what the cells put out.

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CHARGING
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Pb SO4 2 H2O Pb PbO2 1
H 2 H2O NOTE NO HYDROGEN GAS IS MADE IN
THIS REACTION ! Hydrogen is only formed when the
water itself is broken apart (electrolysis).
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ELECTROLYSIS??

• Now what is this???
• When a voltage is applied to water, it is broken
  down into hydrogen gas and oxygen gas.
• This happens at a lower voltage that the charging
  voltage.
• As long as there is lots material for the
  lead/lead oxide/sulfuric acid reaction, that will
  be favored over the electrolysis reaction.
• But if to much voltage is applied, then both
  lead/lead oxide/sulfuric reaction and the
  electrolysis reaction can take place.

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CHARGING VOLTAGESnot all batteries need the same
voltage

• WHY?
• Materials added to the plates causes small
  differences in the voltage required to recharge
• Why would there be other materials added to the
  plates?
• Add Strength or inhibit Hydrogen formation.

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Plate Additives

• Antimony makes the plates stronger BUT adds to
  creation of hydrogen (charging voltage about
  13.8 volts)
• Calcium helps make plates a little stronger, BUT
  it reduces or eliminates hydrogen gas formation
• BUT it requires a higher charging voltage
  (usually about 14. 2 volts)

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Plate Additives

• Antimony because of hydrogen gas formation, the
  cells have access (caps) so that water can be
  replenished and gas (HYDROGEN) can vent (off
  gassing).
• Calcium These are usually seen as sealed or
  maintenance free batteries.
• WHY?

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• Hydrogen gas is formed when a higher voltage is
  applied than required to completely recharge the
  battery.
• ALSO The sulfuric acid solution gets hot and
  boils, thus loosing water.
• AND The water itself is broken down by
  electrolysis.

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• SO, THE RECHARGING VOLTAGE OF DIFFERENT BATTERIES
  IS IMPORTANT.
• More on this later.

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CHARGING RATE
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But First

• AMPS and VOLTS are related
• E (I) x (R)
• Amps (I) amount of electrons flowing
• (R) resistance in the circuit
• E Pressure (like water pressure)
• If we have more amps (flow) then we must push the
  electrons harder (higher voltage)
• It takes a higher voltage to charge at 10 amps
  that to charge at 2 amps! Important later.

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CHARGING RATE

• Approximately one tenth the amp hour rating

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Examples

• 20 amp hour charging rate 2 amps
• 7 amp hour charging rate 0.7 amps
• 70 amp hour charging rate 7 amps

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CHARGERS

• Simple manual chargers have a charging voltage
  of about 15 volts. BE CAREFUL and do not over
  charge the battery or cause formation of hydrogen
  gas.
• Smart Chargers will start the charging at a
  higher voltage (13.9 14.5) and as the battery
  gets closer to full charge, reduces the charging
  voltage. Some will then change to a float
  charge voltage.

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In Your Vehicle or Boat

• Automotive (cranking) batteries designed to
  provide big discharge, for short period, and then
  immediately recharged.
• Why is our radio equipment designed for 13.8
  volts?
• That is the float voltage for most batteries.
• The alternator in your vehicle puts out a higher
  voltage when the battery needs recharging, then
  reduces to 13.8 volts to float it.
• When the battery is charged, the alternator is
  actually supplying the electrical power for the
  vehicle, and also holding the charge in the
  battery for when it is needed later.

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BUT WE MISSED SOME OTHER CHEMISTRY THAT GOES ON
IN A BATTERY!
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Two Other Activities

• First
• Small side reaction Pure sulfur deposits on the
  plates (sulfination).
• Sulfur does not conduct electricity
• Sulfur coats the plate surfaces and prevents the
  chemical reactions, and insulates conductive
  surfaces.

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SULFINATION

• Sulfination is happening all the time.
• Worse in two cases
• Worse when battery is left sitting and not used
  (discharged or charged)
• Recharging helps knock off the sulfur from the
  plates
• Vibration and sloshing also helps (like when in a
  car, boat, truck, RV)

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Low Voltage

• The chemical reaction that causes sulfination is
  faster when the battery is discharged below 11.5
  volts.

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Lead Sulfate

• Second
• During discharge, lead sulfate is deposited on
  the plates (remember)
• A little bit of this falls off the plates and
  settles in the bottom of the battery
• When the lead sulfate is not on the plate, it
  cannot be turned back into lead and lead oxide,
  thus the battery eventually will not be able to
  take much of a charge, or eventually will take no
  charge.

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CAPACITIES OF BATTERIES
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AMP HOURS

• Definition The number of amps the battery can
  deliver at a reasonable discharge rate, for a
  designated amount of time, at a voltage not below
  11.5 volts.

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Amp Hours Examples

• 20 amp hours 1 amp for 20 hours, or, 2 amps for
  10 hours, or 20 amps for one hour, 40 amps for ½
  hour, etc.
• 7 amp hours 1 amp for 7 hours, 3.5 amps for 3.5
  hours, 7 amps for 1 hour, etc.
• 70 amp hours well, you get the picture.

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Reasonable Rate of Discharge???

• About one tenth the amp hour rating
• 20 amp hour battery 2 amps
• 70 amp hour battery 7 amps
• Lead Acid batteries can provide much higher
  discharge rates (i.e., more amps) but sometimes
  at a cost.

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DISCHARGE DONTS

• Max discharge rate before harming the battery is
  about one fourth the amp hours rating
• 20 amp hour battery 5 amps before harm
• 70 amp hour battery 17.6 amps before harm
• 7 amp hour battery 1.75 amps before harm
• Harm is not death, just shortened life.

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DISCHARGE DONTS CONT

• Dont leave partially or heavily discharged
  batteries sit for a long period before
  recharging.
• This increases the sulfination process and allows
  more time for the lead sulfate to fall of the
  plates.
• This shortens the life of the battery

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OTHER HARM

• High discharge rate causes
• Heating of battery
• Over heating can damage plates and connectors of
  cells warping shorts braking
• Overheating can boil sulfuric acid solution
• All these either reduce the life of the battery,
  In the worse case, it can be destroyed.

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BUT DONT BE AFRAID

• Automotive batteries and marine batteries can
  handle short periods of very large discharge
  rates without significantly reducing the life of
  the battery.
• We will talk about how to prolong the life of the
  battery in a little bit.

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BATTERY SIZES

• Most automotive cranking batteries are about 45
  amp hours
• Most marine (or RV or Deep Cycle) batteries or
  70 to 100 amp hours
• Most smaller batteries, such as those found in
  UPSs, alarm backups, etc. are about 5 to 10 amp
  hours.
• Most motorcycle and lawn tractor batteries are
  about 10 15 amp hours.

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DIFFERENT KINDS OF BATTERIES
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FLOODED CELL

• So far we have been looking at what is called a
  flooded cell or wet battery
• The sulfuric acid in solution is a liquid
  sloshing around between the plates.
• Sealed or Maintenance Free batteries have plates
  with calcium which does not allow off gassing
  thus no need to put water in the battery
• Other flooded cells need periodic replenishment
  of the water in the sulfuric acid solution --
  due to evaporation, off gassing, and just plain
  old use.

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GEL CELLS

• Same chemistry and same plates, but the sulfuric
  acid solution is made into a gel, like jello.
• More efficient since the ions in the electrolyte
  is physically closer to the plates
• Do not off gas unless recharged at an over
  voltage
• Sometimes can be installed on side or upside down
  -- consult manufacturer info.
• Act more like a deep cycle battery, can be
  discharged below 11.5 volts with less harm.
• Requires a slower recharge rate than flooded cell
  - can be damaged easier.
• Requires a little higher recharge voltage than
  flooded cell -- Calcium added to the plates.

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AGM

• Absorbed Glass Mat
• The sulfuric acid solution is absorbed on a
  fiberglass mat and held against the plates.
• Strongest construction method - can take more
  bashing.
• Also acts more like a deep cycle battery
• Takes a little slower recharge rate than flooded
  cell can be damaged easier
• Require a little higher initial recharging
  voltage than a flooded cell -- also Calcium.
• Can be mounted in any position (including upside
  down)

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Differences Between Auto and Marine Batteries

• Auto designed differently than marine
• Remember the do not go below 11.5 volts in the
  chemistry section?
• Sulfination and loss of lead sulfate
• But the deep cycle can mean drawing those amps
  from the battery that are available below 11.5
  volts.
• WHY AND HOW?????

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Bigger IS Better

• Average life of auto battery is about 5 years
  (/- depending on how well built)
• To over come the added sulfination and loss of
  lead sulfate, they just put bigger plates into
  marine (RV, deep cycle, etc.) batteries, so that
  they also last about 5 years.
• Life expectancy of a lead acid battery is
  directly related to the plate size and
  discharge/charging usage.
• Use a battery designed for the load.

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PROLONGING THE LIFE OF YOUR LEAD ACID
BATTERYUSE IT OR LOOSE IT
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DONTS

• 1. Leave a battery sitting unused for a long
  time (even if left fully charged at first)
• Leave a discharged or partially discharged
  battery sitting for a long time. Recharge as
  soon a possible.
• Disuse is the biggest killer of batteries.
• WHY? The sulfination process can chug along,
  uninterrupted.

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DONTs

• 3. Over charge (to fast, to long).
• Boil the sulfuric acid.
• Over heat the battery causing mechanical failure
• Use the correct charging amperage
• Under charge
• Use the correct charging voltage (amperage)
• Does not drive the reaction to completion and
  causes sulfation and loss of lead sulfate

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• DOs

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• Stratification (flooded cell only) The acid
  solution at the bottom is strong and at the top
  weak. This messes up battery chemistry.
• Strong recharging stirs up the acid solution as
  it warms up -- but dont boil or over heat.
• Movement (like driving around in our car) sloshes
  the acid solution around.

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• Sulfination Recharging and movement can help
  remove the sulfur deposits.
• The process of heating up and cooling off causes
  expansion and contraction of the plates (again,
  reasonable heating) and helps break off the
  sulfur deposits.
• Movement, like driving you vehicle (vibration,
  hitting bumps, etc.) can help shake the sulfur
  off the plates. It is good to take your battery
  out to the field.

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• Quickly Recharging After Discharge
• Quickly recharging helps prevent lead sulfate
  from falling off the plates. It is changed back
  to lead and lead oxide before it has time to fall
  off.
• The longer a battery sits with lead sulfate on
  the plates, the more of it will fall off.

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• SO, ONCE AGAIN
• THE BEST THING YOU CAN DO FOR A BATTERY IS
• USE IT

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• THE RIGHT CHARGER FOR THE RIGHT BATTERY

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Float Charger

• A float charger will maintain the voltage on the
  battery terminals so that the sulfination
  reaction is minimized.
• A float charger will help prevent self
  discharge, by holding the lead/lead oxide to
  lead sulfate reaction at bay.
• Some Smart Chargers also have the float
  function.

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MORE ON CHARGERS
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Charge your battery from inside the vehicle!
Fully Automatic Battery Charger/Maintainer with
Float Mode Monitoring for 6 and 12 volt
batteries. 2 Amp, 12 Volt/4 Amp, 6 Volt slow
charge with Reverse Hook-Up Protection is ideal
for keeping stored, lead-acid batteries charged
and power maintained at all times. Great for
Motorcycle, Lawn Tractor, ATV, Snowmobile size
batteries and to maintain larger Car, RV, Boat,
Deep Cycle, Antique and Classic Car batteries
too! Includes 50 amp battery clamps, 12V
accessory plug and permanent ring connectors for
fast, easy charging every time. UL listed.
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DieHard 10 amp Manual Battery Charger For cars,
trucks, boats, RVs, farm equipment, motorcycles,
lawn tractors with 12 volt batteries. 10 amp fast
charge for every day charging needs. Charges in 3
to 5 hours. Rust-proof, shock-resistant
polypropylene case for extended life and safety
Solid-state circuitry with silicon diodes for
optimum performance Spark-proof protection in
automatic mode for added safety Copper wound
transformers for long life Reverse hook-up
protection, UL listed
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DieHard 10/2/50 amp. Automatic Battery Charger
12V starter-Charger. Bring a fast, powerful
charge wherever it's needed. For cars, trucks,
boats, RVs, farm equipment, motorcycles, lawn
tractors with 12 volt batteries. 2 LEDs power
on/full charge. Rust-proof, shock-resistant
polypropylene case for extended life and safety
Solid-state circuitry with silicon diodes for
optimum performance Spark-proof protection in
automatic mode for added safety Copper wound
transformers for long life
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• SUMMARY

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• Lead Acid batteries are designed to last
  approximately 5 years when properly used.
• Disuse is the number one killer
• Abuse is the number two killer
• Over charging
• Under charging
• To much discharge
• To high a current discharge
• A battery that is used is a happy battery!

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VOLTAGE DROP DURING USE

• As we use the battery, the voltage drops
• Remember, we dont want to go below 11.5 volts
• But our equipment is designed to function best at
  13.8 volts.
• Some equipment shuts down at about 12 volts.
• Cant get all the amp hours out of the battery

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For equipment that will work down to 11.5 volts

• Radio will not put out full power
• Who cares, unless you need full power
• A 50 watt radio set at 20 watts may actually put
  out 15 watts at 11.8 volts
• But if it only takes 10 watts to reach the other
  station, who cares.

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For Radios That Shut Down Before 11.5 Volts

• BATTERY BOOSTERS

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• Keeps voltage at 13.8 13.6 volts
• If you cant use the amps that are available
  below 12 volts, then you are dragging a lot of
  battery around for not many amp hours

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THE ENDAny Questions?