Battery Tutorial You have most likely heard the
term K.I.S.S. (Keep It Simple, Straight). I am going to attempt
to explain how lead acid batteries work and what they need
without burying you with a bunch of needless technical data.
Actually I have found that battery manufacturer's data will vary
somewhat so I must generalize in some cases.
The commercial use of the lead acid battery is over 100 years
old. The same chemical principal is being used to create energy
that our Great, Great, Grandparents may have used.
If you can grasp the basics you will have fewer battery problems
and will gain greater battery performance, reliability, and
longevity. I suggest you read the entire tutorial, however I
have indexed all the information for a quick read and easy
A battery is like a piggy bank. If you keep taking out and
putting nothing back you soon will have nothing.
Present day chassis battery power requirements are huge. Look at
today’s vehicle and all the electrical devices that must be
supplied. Electronics require a source of reliable power. Poor
battery condition can cause expensive electronic component
failure. Did you know that the average auto has 11 pounds of
wire in the electrical system? Look at RVs and boats with all
the electrical gadgets that require power. I can remember when a
trailer or motor home had a single 12-volt house battery. Today
it is standard to have 2 or more house batteries powering
inverters up to 4000 watts.
Average battery life has become shorter as energy requirements
have increased. Life span depends on usage; 6 months to 48
months, yet only 30% of all batteries actually reach the
48-month mark. A Few Basics The Lead Acid battery is made up of
plates, lead, and lead oxide (various other elements are used to
change density, hardness, porosity, etc.) with a 35% sulfuric
acid and 65% water solution. This solution is called electrolyte
which causes a chemical reaction that produce electrons. When
you test a battery with a hydrometer you are measuring the
amount of sulfuric acid in the electrolyte. If your reading is
low, that means the chemistry that makes electrons is lacking.
So where did the sulfur go? It is resting to the battery plates
and when you recharge the battery the sulfur returns to the
Battery types, Deep Cycle and
Wet Cell, Gel-Cell and Absorbed
Glass Mat (AGM)
CCA, CA, AH and RC; what's that
Selecting and Buying a New
Battery Life and Performance
1. We must think safety when we
are working around and with batteries. Remove all jewelry. After
all you don't want to melt your watchband while you are wearing
the watch. The hydrogen gas that batteries make when charging is
very explosive. I have had 2 batteries blow up and drench me in
sulfuric acid. That is no fun. This is a good time to use those
safety goggles that are hanging on the wall. Sulfuric Acid eats
up clothing and you may want to select Polyester clothing to
wear, as it is naturally acid resistant. I just wear junk
clothes, after all Polyester is so out of style. When doing
electrical work on vehicles it is best to disconnect the ground
cable. Just remember you are messing with corrosive acid,
explosive gases and 100's amps of electrical current.
2. Basically there are two types of
batteries; starting (cranking), and deep cycle (marine/golf
cart). The starting battery (SLI starting lights ignition)
is designed to deliver quick bursts of energy (such as starting
engines) and have a greater plate count. The plates will also be
thinner and have somewhat different material composition. The
deep cycle battery has less instant energy but greater
long-term energy delivery. Deep cycle batteries have thicker
plates and can survive a number of discharge cycles. Starting
batteries should not be used for deep cycle applications. The
so-called Dual Purpose Battery is only a compromise
between the 2 types of batteries.
3. Wet Cell (flooded), Gel Cell, and
Absorbed Glass Mat (AGM) are various versions of the lead
acid battery. The wet cell comes in 2 styles;
serviceable, and maintenance free. Both are filled with
electrolyte and I prefer one that I can add water to and check
the specific gravity of the electrolyte with a hydrometer. The
Gel Cell and the AGM batteries are specialty
batteries that typically cost twice as much as a premium wet
cell. However they store very well and do not tend to sulfate or
degrade as easily or as easily as wet cell. There is little
chance of a hydrogen gas explosion or corrosion when using these
batteries; these are the safest lead acid batteries you can use.
Gel Cell and some AGM batteries may require a special charging
rate. I personally feel that careful consideration should be
given to the AGM battery technology for applications such as
Marine, RV, Solar, Audio, Power Sports and Stand-By Power just
to name a few. If you don't use or operate your equipment daily;
this can lead premature battery failure; or depend on top-notch
battery performance then spend the extra money. Gel Cell
batteries still are being sold but the AGM batteries are
replacing them in most applications. There is a little confusion
about AGM batteries because different manufactures call them
different names; some of the popular ones are sealed regulated
valve, dry cell, non-spillable, and sealed lead acid batteries.
In most cases AGM batteries will give greater life span and
greater cycle life than a wet cell battery.
SPECIAL NOTE about Gel Batteries: It is very common for
individuals to use the term GEL CELL when referring to sealed,
maintenance free batteries, much like one would use Kleenex when
referring to facial tissue or "Xerox machine" when referring to
a copy machine. Be very careful when specifying a battery
charger, many times we are told by customer they are requiring a
charger for a Gel Cell battery and in fact the battery is not a
AGM: The Absorbed Glass Matt construction allows the
electrolyte to be suspended in close proximity with the plateŐs
active material. In theory, this enhances both the discharge and
recharge efficiency. Actually, the AGM batteries are a variant
of Sealed VRLA batteries. Popular usage high performance engine
starting, power sports, deep cycle, solar and storage battery.
The AGM batteries we sell are typically good deep cycle
batteries and they deliver best life performance if recharged
before the battery drops below the 50 percent discharge rate. If
these AGM batteries are discharged to a rate of 100 percent the
cycle life will be 300 plus cycles and this is true of most AGM
batteries rated as deep cycle batteries.
GEL: The gel cell is similar to the AGM style because the
electrolyte is suspended, but different because technically the
AGM battery is still considered to be a wet cell. The
electrolyte in a GEL cell has a silica additive that causes it
to set up or stiffen. The recharge voltages on this type of cell
are lower than the other styles of lead acid battery. This is
probably the most sensitive cell in terms of adverse reactions
to over-voltage charging. Gel Batteries are best used in VERY
DEEP cycle application and may last a bit longer in hot weather
applications. If the incorrect battery charger is used on a Gel
Cell battery poor performance and premature failure is certain.
4. CCA, CA, AH and RC what are these all
about? Well these are the standards that most battery companies
use to rate the output and capacity of a battery.
Cold cranking amps (CCA) is a measurement of the number
of amps a battery can deliver at 0 ° F for 30 seconds and not
drop below 7.2 volts. So a high CCA battery rating is good
especially in cold weather.
CA is cranking amps measured at 32 degrees F. This rating
is also called marine cranking amps (MCA). Hot cranking
amps (HCA) is seldom used any longer but is measured at
80 ° F.
Reserve Capacity (RC) is a very important rating. This is
the number of minutes a fully charged battery at 80 ° F will
discharge 25 amps until the battery drops below 10.5 volts.
An amp hour (AH) is a rating usually found on deep cycle
batteries. If a battery is rated at 100 amp hours it should
deliver 5 amps for 20 hours, 20 amps for 5 hours, etc.
5. Battery Maintenance is an
important issue. The battery should be cleaned using a baking
soda and water mix; a couple of table spoons to a pint of water.
Cable connection needs to be clean and tightened. Many battery
problems are caused by dirty and loose connections. A
serviceable battery needs to have the fluid level checked. Use
only mineral free water. Distilled water is best. Don't overfill
battery cells especially in warmer weather. The natural fluid
expansion in hot weather will push excess electrolytes from the
battery. To prevent corrosion of cables on top post
batteries use a small bead of silicon sealer at the base of the
post and place a felt battery washer over it. Coat the washer
with high temperature grease or petroleum jelly (Vaseline), then
place cable on the post and tighten. Coat the exposed cable end
with the grease. Most folks don't know that just the gases from
the battery condensing on metal parts cause most corrosion.
6. Battery Testing can be done
in more than one way. The most popular is measurement of
specific gravity and battery voltage. To measure specific
gravity buy a temperature compensating hydrometer and measure
voltage, use a digital D.C. Voltmeter. A good digital load
tester may be a good purchase if you need to test batteries
You must first have the battery fully charged. The surface
charge must be removed before testing. If the battery has been
sitting at least several hours (I prefer at least 12 hours) you
may begin testing. To remove surface charge the battery must
experience a load of 20 amps for 3 plus minutes. Turning on the
headlights (high beam) will do the trick. After turning off the
lights you are ready to test the battery.
State of Charge
*Sulfation of Batteries starts when specific gravity falls below
1.225 or voltage measures less than 12.4 (12v Battery) or 6.2 (6
volt battery). Sulfation hardens the battery plates reducing and
eventually destroying the ability of the battery to generate
Volts and Amps.
Load testing is yet another way of testing a battery. Load test
removes amps from a battery much like starting an engine would.
A load tester can be purchased at most auto parts stores. Some
battery companies label their battery with the amp load for
testing. This number is usually 1/2 of the CCA rating. For
instance, a 500CCA battery would load test at 250 amps for 15
seconds. A load test can only be performed if the battery is
near or at full charge.
The results of your testing should be as follows:
Hydrometer readings should not vary more than .05 differences
Digital Voltmeters should read as the voltage is shown in this
document. The sealed AGM and Gel-Cell battery voltage (full
charged) will be slightly higher in the 12.8 to 12.9 ranges. If
you have voltage readings in the 10.5 volts range on a charged
battery, that indicates a shorted cell.
If you have a maintenance free wet cell, the only ways to test
are voltmeter and load test. Most of the maintenance free
batteries have a built in hydrometer that tells you the
condition of 1 cell of 6. You may get a good reading from 1 cell
but have a problem with other cells in the battery.
When in doubt about battery testing, call the battery
manufacturer. Many batteries sold today have a toll free number
to call for help.
7. Selecting a Battery -
When buying a new battery I suggest you purchase a
battery with the greatest reserve capacity or amp hour rating
possible. Of course the physical size, cable hook up, and
terminal type must be a consideration. You may want to consider
a Gel Cell or an Absorbed Glass Mat (AGM) rather than a Wet Cell
if the application is in a harsher environment or the battery is
not going to receive regular maintenance and charging.
Be sure to purchase the correct type of battery for the job it
must do. Remember an engine starting battery and deep cycle
batteries are different. Freshness of a new battery is
very important. The longer a battery sits and is not re-charged
the more damaging sulfation build up there may be on the plates.
Most batteries have a date of manufacture code on them. The
month is indicated by a letter 'A' being January and a number
'4' being 2004. C4 would tell us the battery was manufactured in
March 2004. Remember the fresher the better. The letter "i" is
not used because it can be confused with #1.
Battery warranties are figured in the favor of battery
manufactures. Let's say you buy a 60-month warranty battery and
it lives 41 months. The warranty is pro-rated so when taking the
months used against the full retail price of the battery you end
up paying about the same money as if you purchased the battery
at the sale price. This makes the manufacturer happy. What makes
me happy is to exceed the warranty. Let me assure you it can be
8. Battery life and performance -
Average battery life has become shorter as energy requirements
have increased. Two phrases I hear most often are "my battery
won't take a charge, and my battery won't hold a charge".
Only 30% of batteries sold today reach the 48-month mark. In
fact 80% of all battery failure is related to sulfation
build-up. This build up occurs when the sulfur molecules in the
electrolyte (battery acid) become so deeply discharged that they
begin to coat the battery's lead plates. Before long the plates
become so coated that the battery dies. The causes of sulfation
are numerous. Let me list some for you.
Batteries sit too long between charges. As
little as 24 hours in hot weather and several days in cooler
Battery is stored without some type of
"Deep cycling" an engine starting battery.
Remember these batteries can't stand deep discharge.
Undercharging of a battery, to charge a
battery (letŐs say) to 90% of capacity will allow sulfation
of the battery using the 10% of battery chemistry not
reactivated by the incomplete charging cycle.
Heat of 100 plus F., increases internal
discharge. As temperatures increase so does internal
discharge. A new fully charged battery left sitting 24 hours
a day at 110 degrees F for 30 days would most likely not
start an engine.
Low electrolyte level - battery plates
exposed to air will immediately sulfate.
Incorrect charging levels and settings. Most
cheap battery chargers can do more harm than good. See the
section on battery charging.
Cold weather is also hard on the battery.
The chemistry does not make the same amount of energy as a
warm battery. A deeply discharged battery can freeze solid
in sub zero weather.
Parasitic drain is a load put on a battery
with the key off. More info on parasitic drain will follow
in this document.
There are ways to greatly increase battery
life and performance. All the products we sell are targeted to
improve performance and battery life.
An example: Let's say you have "toys"; an ATV, classic car,
antique car, boat, Harley, etc. You most likely don't use
these toys 365 days a year as you do your car. Many of these
toys are seasonal so they are stored. What happens to the
batteries? Most batteries that supply energy to power our toys
only last 2 seasons. You must keep these batteries from
sulfating or buy new ones. We sell products to prevent and
reverse sulfation. The PulseTech products are patented
electronic devices that reverse and prevent of sulfation. Also
Battery Equaliser a chemical battery additive has proven itself
very effective in improving battery life and performance. Other
devices such as Solar Trickle Chargers are a great option for
Parasitic drain is a load put on a battery with the key
off. Most vehicles have clocks, engine management computers,
alarm systems, etc. In the case of a boat you may have an
automatic bilge pump, radio, GPS, etc. These devices may all be
operating without the engine running. You may have parasitic
loads caused by a short in the electrical system. If you are
always having dead battery problems most likely the parasitic
drain is excessive. The constant low or dead battery caused by
excessive parasitic energy drain will dramatically shorten
battery life. If this is a problem you are having, check out the
Priority Start and Marine Priority Start to prevent dead
batteries before they happen. This special computer switch
will turn off your engine start battery before all the starting
energy is drained. This technology will prevent you from deep
cycling your starting battery.
9. Battery Charging - Remember
you must put back the energy you use immediately. If you don't
the battery sulfates and that affects performance and longevity.
The alternator is a battery charger. It works well if the
battery is not deeply discharged. The alternator tends to
overcharge batteries that are very low and the overcharge can
damage batteries. In fact an engine starting battery on average
has only about 10 deep cycles available when recharged by an
alternator. Batteries like to be charged in a certain way,
especially when they have been deeply discharged. This type of
charging is called 3 step regulated charging. Please note that
only special SMART CHARGERS using computer technology can
perform 3 step charging techniques. You don't find these types
of chargers in parts stores and Wal-Marts. The first step is
where up to 80% of the battery energy capacity is replaced by
the charger at the maximum voltage and current amp rating of the
charger. When the battery voltage reaches 14.4 volts this begins
the absorption charge step. This is where the voltage is
held at a constant 14.4 volts and the current (amps) declines
until the battery is 98% charged. Next comes the Float Step.
This is a regulated voltage of not more than 13.4 volts and
usually less than 1 amp of current. This in time will bring the
battery to 100% charged or close to it. The float charge will
not boil or heat batteries but will maintain the batteries at
100% readiness and prevent cycling during long term inactivity.
Some gel cell and AGM batteries may require special settings or
10. Battery Do's
Think Safety First.
Do read entire tutorial
Do regular inspection and maintenance
especially in hot weather.
Do recharge batteries immediately after
Do buy the highest RC reserve capacity or AH
amp hour battery that will fit your configuration.
11. Battery Don'ts
Don't forget safety first.
Don't add new electrolyte (acid).
Don't use unregulated high output battery
chargers to charge batteries.
Don't place your equipment and toys into
storage without some type of device to keep the battery
Don't disconnect battery cables while the
engine is running (your battery acts as a filter).
Don't put off recharging batteries.
Don't add tap water as it may contain
minerals that will contaminate the electrolyte.
Don't discharge a battery any deeper than
you possibly have to.
Don't let a battery get hot to the touch and
boil violently when charging.
Don't mix size and types of batteries.