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Introduction
Trojan Battery Company has been manufacturing lead-acid batteries for
more than three generations. Our experience has shown that the key
factor to achieving optimum performance and long battery life is a
solid care and maintenance program. This booklet will focus on how to
properly maintain and charge all Trojan lead-acid battery types.
While you
read this brochure, please understand all battery systems are unique.
Battery type, charger technology, equipment loads, cable size, and
climate can all vary. Slight or significant, these differences will
require battery maintenance to be adjusted. So please keep in mind
this booklet is only a guideline for proper battery care. Your
particular system will always require a degree of customized
attention.
Battery
Type
Lead-acid batteries are generally classified by application and by
construction (what they are used for & how they are made). The
primary application is car batteries, sometimes called automotive.
Deep cycle is also a major application but is usually broken down into
more specific applications such as RV, golf cars, floor scrubbers,
renewable energy, marine, and so on.
There are
two popular construction types: Flooded batteries (Wet) and VRLA
batteries (Valve-Regulated Lead Acid). Flooded types contain a wet
electrolyte (acid in water) which can spill if tipped over. However,
in VRLA batteries, the electrolyte is suspended in a gel or a
fiberglass-mat (AGM technology). These batteries are non-spillable.
Before getting started understand which battery type you are involved
with. This booklet will address the charging and maintenance for both
types.
Inspection
There are many tools that may help in properly caring for and
maintaining batteries. Below is a list of basic items that Trojan
recommends for this task:
Recommended
Equipment
| CAUTION: Always wear
protective clothing, gloves, and goggles when handling
batteries and electrolyte |
Just like
looking under the hood of your car and examining the engine will help
you find trouble spots that need maintenance. Your batteries should
also be carefully inspected on a regular basis in order to detect and
correct potential problems before they can do harm. It is a great idea
to start this routine when you first receive your batteries. Here is a
guideline on what to look for:
- Examine
the outside appearance of the battery.
- Look
for cracks in the container
- Repair
or replace any damaged batteries.
- The
top of the battery, the posts, & connections should be clean,
free of dirt, fluids, and corrosion.
- If
batteries are dirty, refer to the Cleaning
section for the proper cleaning procedure.
- Any
fluids on or around the battery is an indication that electrolyte
is spilling, leaching, or leaking out.
- Leaking
batteries must be repaired or replaced.
- Check
all battery cables and their connections.
- Look
closely for loose or damaged parts.
- Battery
cables should be intact; broken or frayed cables can be extremely
hazardous.
- Replace
any cable that looks suspicious.
- Tighten
all wiring connections to the proper specification (see below).
Make certain there is good contact with the terminals.
Proper Torque Values for Connection Hardware
| Flooded |
65 to 75
in-lbs |
| VRLA |
90 to 100
in-lbs |
| WARNING: Do not
overtighten terminals. Doing so can result in post breakage,
post meltdown, and fire. |
Testing
Visual inspection alone is not sufficient to determine the overall
health of the battery. Both voltage and specific gravity readings of
each cell will give a good indication of the battery’s charge level,
age, and health. Routine voltage and gravity checks will not only show
the state of charge but also help spot signs of improper care (like
undercharging, overwatering, etc.) and possibly even locate a bad or
weak battery. The following steps outline how to properly perform
routine voltage and specific gravity testing on your batteries.
|
I. Specific
Gravity Test
(Flooded batteries only)
(Do not add water at this time)
- Fill
and drain the hydrometer 2-4 times before pulling out a sample.
- There
should be enough sample electrolyte in the hydrometer to
completely support the float.
- Take
a reading, record it, and return the electrolyte back to the
cell.
- To
check another cell, repeat the 3 steps above.
- Check
all cells in the battery.
- Replace
the vent caps and wipe off any electrolyte that might have been
spilled.
- Correct
the readings to 80 °F:
- Add
.004 to readings for every 10° above 80°F
- Subtract
.004 for every 10° below 80°F.
- Compare
the readings.
- Check
the state of charge using Table 1
|
The
readings should be at or above the factory specification of 1.277 (±
.007). If any specific gravity readings register low, then follow
the steps below. |
- Check
and record voltage level(s)
- Put
battery(s) on a complete charge.
- Take
specific gravity readings again.
|
If any
specific gravity readings still register low then follow the steps
below. |
- Check
voltage level(s).
- Perform
equalization charge. Refer to the Equalizing
section for the proper procedure.
- Take
specific gravity readings again.
|
If any specific gravity reading still registers lower than the
factory specification of 1.277 (± .007) then one or more of the
following conditions may exist: |
- The
battery is old and approaching end of life.
- The
battery was left in a state of discharge too long.
- Electrolyte
was lost due to spillage or overflow.
- A
weak or bad cell is developing.
- Battery
was watered excessively previous to testing
Batteries
in conditions 1 - 4 should be taken to a specialist for further
evaluation or retired from service.
|
II. Open-Circuit Voltage Test
For accurate voltage readings batteries must remain idle (no
charging, no discharging) for at least 6 hrs, preferably 24. |
- Disconnect
all loads from the batteries.
- Measure
the voltage using a DC voltmeter.
- Correct
the readings to 80°F
- Add
.028 per cell for every 10° above 80°F
- Subtract
.028 per cell for every 10° below 80°F.
- Check
the state of charge with Table 1.
- Charge
the battery if it registers 0%-70% charged
|
If battery
registers below the Table
1
values, the following conditions may exist: |
- The
battery was left in a state of discharge too long.
- The
battery has a bad cell.
Batteries
in these conditions should be taken to a specialist for further
evaluation or retired from service.
|
Table
1. State of Charge as related to Specific Gravity and
Open-Circuit Voltage
| Percentage
of Charge |
Specific
Gravity
Corrected to 80°
F
|
Open-Circuit
Voltage |
| 6V |
12V |
24V |
36V |
48V |
| 100 |
1.277 |
6.37 |
12.73 |
25.46 |
38.20 |
50.93 |
| 90 |
1.258 |
6.31 |
12.62 |
25.24 |
37.85 |
50.47 |
| 80 |
1.238 |
6.25 |
12.50 |
25.00 |
37.49 |
49.99 |
| 70 |
1.217 |
6.19 |
12.37 |
24.74 |
37.12 |
49.49 |
| 60 |
1.195 |
6.12 |
12.24 |
24.48 |
36.72 |
48.96 |
| 50 |
1.172 |
6.05 |
12.10 |
24.20 |
36.31 |
48.41 |
| 40 |
1.148 |
5.98 |
11.96 |
23.92 |
35.87 |
47.83 |
| 30 |
1.124 |
5.91 |
11.81 |
23.63 |
35.44 |
47.26 |
| 20 |
1.098 |
5.83 |
11.66 |
23.32 |
34.97 |
46.63 |
| 10 |
1.073 |
5.75 |
11.51 |
23.02 |
34.52 |
46.03 |
|
Watering
(flooded batteries only)
Just like cars need oil, flooded batteries need water. More so,
watering must be done at the right time and in the right amount or
else the battery’s performance and longevity suffers. There are two
levels for a batteries water. First, when a battery is discharged
(partially or fully)the water only needs to cover the plates. Second,
after fully charging the battery, the best level is just below the end
of the plastic filling well. Keeping the water of the 2nd
level will prevent having to worry about the 1st level. |
The most
important things to avoid: |
- Don’t
let the plates get exposed to air. This will damage (corrode) the
plates.
- Don’t
fill the water level up the filling well to the cap. This most
likely will cause the battery to overflow acid, consequently
losing capacity and making a corrosive mess.
- Do not
use water with a high mineral content. Use distilled or deionized
water only.
|
How often do I water my batteries?
This depends on your climate, charging methods, appplication, etc.
Trojan simply recommends that to check the batteries once a month
until you get a feel for how thirsty your batteries are. |
| CAUTION: The
electrolyte is a mix of acid and water so skin contact should be
avoided. |
| Step by
step watering procedure: |
- Minimum
electrolyte level is at the top of the plates.
- Open
the vent caps and look inside the fill wells.
- If
necessary add just enough water to cover the plates at this time.
- Put
batteries on a complete charge before adding any additional water
(refer to the Charging section).
- Charge
batteries completely
- Open
the vent caps and look inside the fill wells.
- Add
water until the electrolyte level is 1/8" below the bottom of
the fill well.
- A
piece of rubber can be used safely as a dipstick to help determine
this level.
- Clean,
replace, and tighten all vent caps.
| WARNING: Never
add acid to a battery. |
|
Cleaning
Batteries seem to attract dust, dirt, and grime. Keeping them clean
will help one spot trouble signs if they appear and avoid problems
associated with grime. |
- Check
that all vent caps are tightly in place.
- Clean
the battery top with a cloth or brush and a solution of baking
soda and water.
- When
cleaning, do not allow any cleaning solution, or other foreign
matter to get inside the battery.
- Rinse
with water and dry with a clean cloth.
- Clean
battery terminals and the inside of cable clamps using a post and
clamp cleaner.
- Clean
terminals will have a bright metallic shine.
- Reconnect
the clamps to the terminals and thinly coat them with petroleum
jelly (Vaseline) to prevent corrosion.
- Keep
the area around batteries clean and dry also.
|
Storage
Periods of inactivity can be extremely harmful to lead-acid batteries.
When placing a battery into storage, follow the recommendations below
to insure that the battery remains healthy and ready for use.
| NOTE: Storing,
charging or operating batteries on concrete is perfectly OK. |
|
The most
important things to avoid: |
- Freezing.
Avoid locations where freezing temp. is expected. Keeping battery
at a high state of charge will also prevent freezing. Freezing
results in irreparable damage to battery’s plates and container.
- Heat.
Avoid direct exposure to heat sources, such as radiators or space
heaters. Temp’s above 80 deg. F accelerate the battery’s
self-discharge characteristics .
|
Step by step
storage procedure: |
- Completely
charge the battery before storing.
- Store
the battery in a cool, dry location, protected from the elements.
- During
storage, monitor the specific gravity (flooded) or voltage.
Batteries in storage should be given a boost charge when they show
a 70% charge or less. See Table 1.
- Completely
charge the battery before re-activating.
- For
optimum performance, equalize the batteries (flooded) before
putting them back into service. Refer to the Equalizing
section for this procedure.
|
Charger Selection
Most deep cycle applications have some sort of charging system already
installed for battery charging (e.g solar panels, inverter, golf car
charger, alternator, etc.). However, there are still systems with deep
cycle batteries where an individual charger must be selected. The
following will help in making a proper selection.
There are
many types of chargers available today. They are usually rated by
their start rate, the rate in amperes that the charger will supply at
the beginning of the charge cycle. When selecting a charger, the
charge rate should be between 10% and 13% of the battery’s 20-hour
AH capacity. For example, a battery with a 20-hour capacity rating of
225 AH will use a charger rated between approximately 23 and 30 amps
(for multiple battery charging use the AH rating of the entire bank).
Chargers with lower ratings can be used but the charging time will be
increased.
Trojan
recommends using a 3-stage charger. Also called "automatic",
"smart" or "IEI" chargers, these chargers prolong
battery life with their well programmed charging profile. These
chargers usually have three distinct charging stages: bulk,
acceptance, and float.
|
Table
2. Charger Voltage Settings for Flooded Batteries
| Charger
Voltage Setting |
System
Voltage |
| 6V |
12V |
24V |
36V |
48V |
| Daily
Charge |
7.2
— 7.4 |
14.4
— 14.8 |
28.8
— 29.6 |
43.2
— 44.4 |
57.6
— 59.2 |
| Float |
6.6 |
13.2 |
26.4 |
39.6 |
52.8 |
| Equalize |
7.8 |
15.5 |
31.0 |
46.5 |
62.0 |
Table
3. Charger Voltage Settings for VRLA Batteries
| |
Charger
Voltage Setting |
System
Voltage |
| 12V |
24V |
36V |
48V |
| Gel
Battery |
Daily
Charge |
13.8
— 14.1 |
27.6
— 28.2 |
41.4
— 42.3 |
55.2
— 56.4 |
| Float |
13.5 |
26.4 |
39.6 |
52.8 |
| AGM
Battery |
Daily
Charge |
14.4
— 14.8 |
28.8
— 29.6 |
43.2
— 44.4 |
57.6
— 59.2 |
| Float |
13.5
— 13.8 |
27.0
— 27.6 |
40.5
— 41.4 |
54.0
— 55.2 |
|
Charging
Charging batteries properly requires administering the right
amount of current at the right voltage. Most charging equipment
automatically regulates these values. Some chargers allow the user to
set these values. Both automatic and manual equipment can
present difficulties in charging. Tables 2
& 3 list most of the necessary voltage
settings one might need to program a charger. In either case the
original instructions for your charging equipment should also be
referenced for proper charging. Here is list of helpful items to
remember when charging: |
- Become
familiar with and follow the instructions issued by the charger
manufacturer.
- Batteries
should be charged after each period of use.
- Lead-acid
batteries do not develop a memory and need not be fully discharged
before recharging.
- Charge
only in well-ventilated area. Keep sparks or flames away from a
charging battery.
- Verify
charger voltage settings are correct (Table 2)
- Check
water level (see the Watering
section).
- Tighten
all vent caps before charging.
- Prevent
overcharging the batteries. Overcharging causes excessive gassing
(water breakdown), heat buildup, and battery aging.
- Prevent
undercharging the batteries. Undercharging causes stratification.
- Do not
charge a frozen battery.
- Avoid
charging at temperatures above 120 °F.
|
Additional
VRLA Charging Instructions: |
- Become
familiar with and follow the instructions issued by the charger
manufacturer.
- Verify
charger has necessary VRLA setting
- Set
charger to VRLA voltage settings (Table 3)
- Do not
overcharge VRLA batteries. Overcharging will dry out the
electrolyte and damage battery.
| WARNING: Do
not equalize VRLA batteries |
|
Equalizing
(flooded batteries only)
Equalizing is an overcharge performed on flooded lead-acid batteries
after they have been fully charged. It reverses the buildup of
negative chemical effects like stratification, a condition where acid
concentration is greater at the bottom of the battery than at the top.
Equalizing also helps to remove sulfate crystals that might have built
up on the plates. If left unchecked, this condition, called sulfation,
will reduce the overall capacity of the battery. |
How often do I equalize ?
Many experts recommend that batteries be equalized periodically.
Ranging anywhere from once a month to once or twice per year. However,
Trojan only recommends equalizing when low or wide ranging specific
gravities (+/-.015) are detected after fully charging a battery. |
Step by Step
Equalizing: |
- Verify
the battery(s) are flooded type.
- Remove
all loads from the batteries.
- Connect
battery charger.
- Set
charger for the equalizing voltage (Table 2).
- Start
charging batteries
- Batteries
will begin gassing and bubbling vigorously
- Take
specific gravity readings every hour
- Equalization
is complete when specific gravity values no longer rise during the
gassing stage
| NOTE: Many
chargers do not have an equalization setting so this procedure
can’t be carried out. |
|
Discharging
Discharging batteries is entirely a function of your particular
application. However, below is list of helpful items:
- Shallow
discharges will result in a longer battery life
- 50%
(or less) discharges are recommended
- 80%
discharge is the maximum safe discharge
- Do not
fully discharge flooded batteries (80% or more). This will damage
(or kill) the battery. Equivalent to overheating a car’s engine,
extent of damage unknown.
- Many
experts recommend operating batteries only between the 50% to 85%
of full charge range. A periodic equalization charge is a must
when using this practice.
- Do not
leave batteries deeply discharged for any length of time.
- Lead-acid
batteries do not develop a memory and need not be fully discharged
before recharging
- Batteries
should be charged after each period of use.
- Batteries
that charge up but cannot support a load are most likely bad and
should be tested. Refer to Testing
section for proper procedure.
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