TAKING CARE OF YOUR BATTERY
Visually inspect your battery every two to six months to
ensure its life-longevity. Below is a list of factors that directly
influence battery performance, and should be checked periodically:
- Corrosion, dirt and/or oil
on the battery case, connectors, and/or posts – Can lead
to blockage in the flow of electric current (connectors and posts) or
promote resistance (battery case). If dirty or corroded, clean the
connectors using a wire brush dipped in a water/baking soda solution
(Use one pound of baking soda to one gallon of water). Rinse with water
and dry with a clean cloth. A thin coat of battery corrosion inhibitor
or petroleum jelly (Vaseline) can be applied to the posts and
connectors to help avoid future corrosion.
- Fluids on or around the
battery – This may be an indication that electrolyte is
spilling or leaking out. If this is the case, repair or replace the
- Loose or damaged battery
cables and connections - Battery cables should be intact, and
the connectors tight at all times. Broken or frayed cables can be
extremely dangerous. Replace any cable that appears damaged.
- Electrolyte level -
Check the fluid level in your battery. If necessary, refill with water.
Distilled water is most recommended, although any water that is safe to
drink (with the exception of mineral waters) is safe to use in a
battery. Do not use water with a known high mineral content. Metal
impurities in the water will lower the performance ability of the
battery. Be cautious not to overfill the battery cells, particularly in
warm/hot weather. The natural fluid expansion that occurs with heat
will push the electrolyte from the battery.
- Inactivity - Lack
of use can be very harmful to lead-cell batteries. If not using on a
regular basis, periodically recharge the battery fully and store it in
a cool place. Avoid extremely hot or cold temperatures. If storage time
exceeds two months, it may be necessary to fully recharge the battery
before re-installing it.
TESTING YOUR BATTERY
In addition to visual inspection, periodic battery testing
is an important preventative procedure. These are common tests used to
determine the charge status of your battery:
Open Circuit Voltage (OCV) Test:
- In order to get an accurate reading of the battery’s
charge, remove the battery from the vehicle, or lift the non-grounded
lead, so as to turn off all electrical loads. CAUTION: This will cause
memory settings, such as clocks, automatic seat adjustments, etc. to be
- Allow the battery to sit idle for a period of 4-6 hours.
- Connect a voltmeter to the positive and negative terminals
and measure the terminal voltage with no loads or chargers connected to
- Compare the OCV reading on the voltmeter with the table
below. Please keep in mind that this table assumes a fully charged
specific gravity of 1.265.
STATE OF CHARGE
vs. OPEN CIRCUIT VOLTAGE
STATE OF CHARGE
- If the volt reading registers below 75%, the battery needs
to be re-charged. If the volt reading is lower than the values shown on
the chart, take the battery to a battery specialist for further
Specific Gravity Test
(Wet/Flooded cell batteries with removable vent caps only):
Check the electrolyte level to ensure it is above the top of the
plates. If not, add water accordingly and charge before taking readings.
If electrolyte is above the plates, make sure not to add any water to
the battery cells to ensure an accurate reading.
Remove the vent caps from the cells.
- Insert a hydrometer into one of the battery cells and draw
liquid into the syringe a few times before pulling out a sample, so
that the float reaches the same temperature as the electrolyte. This
will increase the accuracy of your reading.
- Draw enough liquid from the cell such that the hydrometer
is full enough to fully support the float.
- Take a reading, record it, and return the electrolyte to
the battery cell.
- Repeat this procedure with each individual cell.
- Replace the vent caps and neutralize any liquid that might
have spilled using a water/baking soda solution (Use one pound of
baking soda to one gallon of water). The solution will fizzle when in
the presence of acid. When the fizzing
stops, wipe it off with a damp cloth and then dry.
- Adjust each reading to 80°F. Hydrometers are calibrated
at this temperature, so in order to get the accurate gravity
measurement, add .004 to each reading for every 10o above 80o F and
subtract .004 for every 10o below 80o F.
- Compare each reading to the chart below. If any fall below
1.155 the battery needs to be recharged. A variation of 0.050 or more
between the highest and the lowest cell indicates internal damage in
the battery. If such is the case, the battery needs to be replaced.
Please keep in mind that this table assumes a fully charged specific
gravity of 1.265.
vs. SPECIFIC GRAVITY
This test is used by professional technician to determine whether a
battery needs replacement or not. It consists of a 15-second discharge
of the battery at 1/2 the cold cranking amp level. It is a more
accurate method than the ones listed above.
MORE ON CHARGING:
- New batteries should be given a full charge before use.
- Not recharging a battery after each use causes the battery
to sulfate and affects performance and longevity.
- Avoid charging at temperatures above 120ºF.
- Do not charge a frozen battery.
- As batteries age their maintenance requirements change.
This could mean longer charging time and/or higher finish rate (higher
amperage at the end of the charge). Usually their capacity decreases
and they need to be watered more often (if they are vented with
removable vents to allow watering).
- Always use a matched voltage charger and battery pack
system. An undersized charger will never get the job done no matter how
long you let it run. An oversized charger will cause excess gassing and
heat; this situation could cause explosions and/or other damages.
- Do not overcharge batteries.
- The alternator is a battery charger. It works well if the
battery is not deeply discharged.
- Deeply discharged batteries can be recharged using these
1. Bulk charge
– This stage is performed to return 80% percent of the battery
energy quickly. Amperage is kept as high as the battery and the charger
allow. When the battery voltage reaches approximately 2.41 volts per
cell (14.5 volts for a 12-volt battery) absorption charge is initiated.
2. Absorption charge
- current into the battery is limited to hold the terminal voltage at a
constant 14.4 V. During this time, the battery is allowed to slowly
absorb approximately 20% of the electricity being returned in the
3. Float charge: the
battery is held at a specified voltage that is well below its gassing
point, but high enough that the remaining 5% of capacity can be
returned. Typical float voltage for a 12 volt lead acid battery might
be 13.1 volts. A battery can be left on float charge for extended
periods of time without damage or excessive water loss. However, since
there will be some water loss, periodically check electrolyte levels
and water when necessary. This type of charge will maintain the battery
at 100% readiness and prevent cycling during long term inactivity.
This process should be carried out periodically on wet/flooded
batteries ONLY to prevent stratification and sulfation. It consists of
running a low-current overcharge after the normal charge cycle has been
completed. The extra charge helps keep all cells in balance.
1. Make sure that you
are working with a flooded/wet type of battery.
2. Remove all current
sources from the battery
3. Connect battery
charger (Make sure you are working with a charger that has an
4. Set the charger at
the proper equalizing voltage.
5. Start charge.
6. Batteries will
begin to gas and bubble vigorously.
7. Take gravity
readings every hour.
8. Equalizing is
complete when the gravity values no longer rise during the gassing
Sulfation is the formation of lead sulfate crystals on the plates of a
lead acid battery that can occur in the following conditions:
- Battery sits too long between charges. This can mean
anywhere from a 24-hour period in extreme hot weather to several days
in cooler weather
- Battery is stored without some type of energy input.
- Deep cycling a starting battery.
- Battery is undercharged – even at 90% charge,
sulfation can occur with the remaining 10% of battery chemistry not