COMMERCIAL TRUCKS & FLEETS - AGM VRLA Batteries

COMMERCIAL TRUCKS & FLEETS

AGM VRLA Batteries

PROPER UTILIZATION • TESTING • CHARGING • SYSTEMS INFORMATION

TECHNICAL GUIDE

I: UNDERSTANDING AGM

AND ITS VRLA DESIGN

II: UNDERSTANDING A NECESSARY

EVOLUTION OF COMMERCIAL TRUCK

AGM TECHNOLOGY

III: PROPERTIES OF AGM PRODUCTS AND

SERVICE IN COMMERCIAL VEHICLES

IV: TESTING CONSIDERATIONS

OF AGM DESIGNS

V: CHARGING CONSIDERATIONS

OF AGM DESIGNS

VI: COMMERCIAL BATTERY SYSTEMS

VII: ENVIRONMENTAL TEMPERATURES

AND VENTING CONDITIONS

VIII: SAFETY PRECAUTIONS

FOR AGM BATTERIES

I. UNDERSTANDING AGM

AND ITS VRLA DESIGN

AGM (Absorbed Glass Mat) batteries are constructed with a

VRLA (Valve Regulated Lead Acid) design and can be substituted

in virtually any flooded lead battery application (in conjunction

with well-regulated charging). Their unique features and benefits

deliver an ideal solution for many applications where traditional

flooded batteries would not deliver the best results.

East Penn has been manufacturing valve-regulated batteries

using tried and true technology backed by more than 75 years

of experience. East Penn produces AGM, Gel, Flooded, and

Lithium-ion batteries for many applications. This diverse

product offering enables East Penn to be objective as to the

advantages of each type of battery.

WHAT IF YOU DON’T UNDERSTAND SOMETHING IN

THIS TECHNICAL GUIDE? We are here to help. Go to

https://fahrenheit31.com and type your question in the

Fahrenheit

Hotline section. A battery expert will be happy

to help answer your questions.

A. AGM (Absorbed Glass Mat) batteries

The electrolyte in AGM batteries is completely absorbed in

separators consisting of matted glass fibers. This causes them

to be spillproof, meaning they don’t leak acid like a flooded

design if tipped on their side. The glass mats in AGM batteries

are wrapped around either the positive or negative plates,

which helps prevent damage from vibration and will extend

cycling. The battery’s groups are packed tightly in the case

partitions also protecting its power producing components.

B. How VRLA works

A VRLA battery utilizes a one-way, pressure-relief valve system

to achieve a “recombinant” technology. This means that the

oxygen normally produced on the positive plate is absorbed by

the negative plate. This suppresses the production of hydro-

gen at the negative plate. Water (H

O) is produced instead,

retaining the moisture within the battery. It never needs

watering and should never be opened as this would expose

the battery to excess oxygen from the air. In addition to

damaging the battery, opening it also voids the warranty.

C. The difference between VRLA and traditional

flooded batteries

Flooded electrolyte batteries do not have special one-way,

pressure-relief valves, as they do not work on the recombina-

tion principle. Instead, flooded designs utilize a vent to allow

gas to escape. They contain liquid electrolyte that can spill and

cause corrosion if tipped or punctured. They should not be

used near sensitive electronic equipment. They can only be

installed “upright.” Flooded batteries are more susceptible

to the following conditions; however, these can also be

damaging to VRLA designs as well:

• Left in a discharged condition for any length of time (due

to sulfation). This is especially true of designs that require

water maintenance.

• Continually over-discharged (due to active material shedding).

This is especially true of commercial starting types.

D. Why use AGM Batteries?

Many of today’s heavy-duty trucks depend on batteries to do

much more than crank the engine. Starting batteries alone

aren’t designed to withstand the continuous discharge and

recharge that new auxiliary equipment and anti-idling law

demands. AGM batteries recharge faster and have twice the

cycle life of a conventional flooded product. AGM designs are

also 20x more vibration resistant, which is critical for com-

mercial vehicles that undergo intense use. With the electrolyte

suspended in the glass mats, they are completely spillproof

and more resistant to corrosion.

E. Why use AGM instead of Gel?

Gel batteries are also a VRLA design but are no longer preva-

lent in today’s commercial truck industry. While a Gel battery

is better suited for super-deep discharge applications, due to

the physical properties of the gelled electrolyte, Gel battery

power declines faster than an AGM battery as the temperature

drops below 32°F (0°C). AGM batteries excel for high current,

high power applications and in extremely cold environments.

AGM batteries deliver a better dual-purpose solution for a

combination of starting and accessory power.

F. Why use AGM instead of Lithium-ion?

Lithium-ion is a prevalent technology in EV trucks and some

applications but is still a niche in the Internal Combustion

engine commercial trucks. Its high-power density comes with

a high cost that is not suitable for most owner/operators or

fleets. Also, as an industry that is very conscientious about

recyclability and green initiatives, Lithium-ion does not yet

have a good end-of-life solutions while AGM batteries,

along with other lead battery products, are the most recycled

consumer products in the world.

G. Can I mix batteries within

the same battery pack?

No, you cannot mix AGM, Gel, and flooded batteries within

the same battery pack. Batteries should be paired together

with other batteries of similar age and ratings within the

same battery pack.

II. UNDERSTANDING A NECESSARY

EVOLUTION OF COMMERCIAL TRUCK

AGM TECHNOLOGY

A. The need for protection

against high temperatures

Since 2011, truck designs have caused battery boxes to reach

much higher temperatures – some even 140°F and beyond.

Temperatures keep rising. Instead of directing the vehicle’s air

flow to help cool the engine and other critical parts below the

vehicle, a truck’s cooling airflow is now up, over and behind

the vehicle to achieve better aerodynamics and fuel economy.

Heat generating items are positioned very close to the battery

box causing the temperature in this metal box to continue to

rise. Even in northern regions where high heat was traditionally

not a problem, trucks are experiencing higher temperatures as

a result of these high heat occurrences combined with heavier

power demands.

The evolution of trucks continues to require the heavier cycle

service performance of an AGM product, so flooded products

are becoming less of an option. Protection against heat and a

special AGM reinforced cycle service design better equips the

battery to withstand the grueling demands of extra electrical

demand and key-off loads, especially in high heat environ-

ments and even under normal operating temperatures.

B. What technology helps

protect against high heat?

Fahrenheit

batteries are designed with a revolutionary

Thermal Shielding technology that provides the reinforced

service life critical in Class 6, 7, and 8 trucks (2011 and

newer). Thermal Shielding Technology is comprised of three

main parts:

• Life Extending Catalyst: The catalyst protects an AGM’s

battery recombination process by reducing internal heat

and resisting thermal runaway. Use of the catalyst also

reduces internal corrosion and accelerated aging. (The

catalyst actually creates a superior VRLA design,

especially for high heat situations. High heat causes

overcharging. Commercial batteries with an AGM design

significantly benefit from having this superior VRLA

performance to withstand the effects of overcharging)

• Fahrenheit

Case & Cover: Reinforced design helps

safeguard performance from high heat. A Valve Regulated

design has the propensity to experience bulging if it over-

charges or reaches excessive temperatures. Excessive

bulging is not good for an AGM design as it is built with an

optimized amount of component compression to maximize

performance. Fahrenheit technology protects that compo-

nent protection to safeguard battery performance in high

temperatures.

• TempX Alloy: Strategic Alloy Technology to resist high

heat and optimize the current flow within the battery.

C. Are “Pure Lead” batteries a

suitable solution for high heat?

While lead purity helps minimize gassing when internal chem-

ical reactions are accelerated because of heat, it does NOT

reduce it enough to equal the benefits of a catalyst-enhanced

VRLA design like Fahrenheit. Plus, there are conductivity and

reinforcement trade-offs by not utilizing other elements within

the alloy – especially for commercial truck use. Fahrenheit

products are engineered with a strategic grid alloy formula

with high lead purity, specifically tailored to match the com-

mercial truck application and improve the conductivity of the

mass-to-grid interface. An enhanced mass-to-grid interface

optimizes the battery’s power delivery and promotes long life.

East Penn’s strategic alloy formula provides grids with cor-

rosive tolerance, conductive performance, and manufactured

integrity and is a better overall solution than just “pure lead.”

This has been proven in tests where Fahrenheit was compared

against leading “pure lead” AGM batteries on cycle life and

water loss. Fahrenheit batteries tested at 158°F had 43%*

more cycle life than competitors. Fahrenheit batteries tested

at 140°F resulted in 88%** less water loss than leading “pure

lead” products in the market today. Less water loss equates to

much longer field performance before battery failure.

(*Tests conducted at 167°F comparing Fahrenheit and Standard AGM batteries. Voltage and cycles

measured after 10 seconds and 200 AMP load. ** Testing based on High Float Temp Charge Water

loss test data. Charged at 14.2 volts at 140°F, weighed twice a week and then subjected to BCI Load

Test. Others based on 2 part number, 2 sample average. Fahrenheit on 2 sample average.)

D. Are Fahrenheit

batteries a

suitable solution for cold?

Batteries experience so much heat in warmer months that they

lose the necessary capacity and resiliency to have the power

needed for winter temperatures. One of the best methods to

protect battery performance in the cold is to protect it from

the heat. Battery designs with some type of thermal or heat

protection are best equipped to maximize the truck’s electrical

system performance in the hot or cold.

It’s also important to note that even in Northern regions where

high heat has not traditionally been a problem, battery box

temperatures are reaching beyond recommended operating

temperatures. Fahrenheit Thermal Shielding products are not

only exceeding expectations in high heat performance but also

extending cycle life under normal operating temperatures.

III. Properties of AGM Products and

Service in Commercial Vehicles

Today’s commercial applications are being integrated with more

electronic and accessory power demands than ever before. New

advances in the vehicle’s electrification and battery-powered

controls are requiring a greater demand on the batteries’ func-

tions in the vehicle. Independently powered HVAC and APU

systems require a deeper cycle service that also differs from

the predominate starting service of traditional battery designs.

In most cases, it is not enough to just meet the commercial

vehicle’s starting requirements. Understanding the cycling

or deep cycle demands placed on the battery as well as the

individual user’s needs is extremely critical. AGM batteries can

provide solutions to these additional requirements on the bat-

tery, and it’s extremely important to understand how they can

benefit the many functions batteries serve in today’s

commercial vehicle electrical systems.

A. Starting Service

The predominate function that batteries serve in commer-

cial vehicles is to start the vehicle. However, there are other

demands that today’s battery must withstand in order to

continue to provide that service. AGM batteries offer a du-

rability-enhanced design that reinforces the battery so it can

continue to deliver dependable starting power, even under

demanding auxiliary loads. While the battery’s durability is

becoming more and more important, it does not negate the

fact that the batteries must meet or exceed the vehicle’s Cold

Cranking requirements. AGM batteries excel for high current,

high starting power demanding applications, especially in

extremely cold environments.

Cold Cranking Amps (CCA) is a measure of engine starting

ability based on being able to sustain a minimum voltage

(7.20) under load for a minimum time period (30 seconds) at

a temperature of 0°F. The test is done on a new fully charged

battery. Regardless of the actual low temperature, typical

cranking duration, minimum acceptable voltage, and lowest

expected state of charge; engine manufacturers set their

battery requirements relative to this standard reference value.

CCA is also measured by some battery testers. Here it is a

calculated value proportional to battery conductance and not

the results of a standard test.

B. Cycle Life

Cycle life is how many times you can discharge a battery and

recharge the battery again before it degrades to the point it is no

longer usable. A battery with extended cycle life survives longer

than average under the more grueling demands of less-than-

ideal environments and tough commercial use. This includes

warmer climates, higher temperature environments, longer than

typical hours of usage, higher annual miles of operation, and

frequent electrical loading while the engine is off.

The appropriate test for cycle life depends on how the battery

is going to be used. As a general rule, high temperature

accelerates aging and deeper discharging accelerates capacity

degradation giving fewer cycles. Different tests have different

definitions of end of life. Some users may be able to tolerate

more degradation. If the battery is undersized for its duty, a

user may experience problems before the defined end of life.

It’s important to remember that if you use energy, you must

replace it all, plus an allowance for inefficiency. If you add

extra loads to a vehicle, the charging system may be too small

to recharge in the time available.

1. Cycle life testing

Good cycle life performance depends on the criteria of the

test. For example, if one test shows a battery can perform

1000 cycles, that could be good or bad depending on the

test’s criteria. 500 cycles might be an excellent performance

on one test but on another test 500 cycles might indicate

poor performance.

SAE J2185 is a popular test to determine the effects that

cycling will have on the battery’s starting performance. A 25-

amp, 1-hour discharge is used to mimic the key-off loads at

122°F. The recharge is accelerated to 2.5 hours. After 26

cycles, there is a rest and a 50-second cranking simulation.

The battery could fail during the 25-amp discharge, but in

practice, the cranking simulation is the typical point of failure.

A single 25 ampere-hour cycle could represent one day of

service in a vehicle with excessive hotel loads, or it could

represent over a week of loads in a day cab vehicle.

The fact that this is an individual battery test should be consid-

ered when evaluating the three or four battery system typical

in many commercial trucks. In these systems, a single battery

is supplying one-third or one-fourth of the vehicle’s needs.

IMPORTANT NOTE – There may be charging compatibility

issues within AGM battery types

Off-truck chargers need to recognize the number of amps

absorbed in order to charge properly. This is called charge

reflection. Some AGM batteries have a charge reflection

that does not work with popular shop chargers. This can

cause incompatibility issues leading to inaccurate testing

and improper charging increasing battery replacement and

unnecessary costs. Fahrenheit or East Penn AGM Group 31

batteries do not have these incompatibility issues.

2. Depth of Discharge and Cycle Life

Depth of discharge will affect cycle life. The harder any battery

has to work, the sooner it will fail. The shallower the average

discharge, the longer the life.

It’s important to size a battery system to deliver at least twice

the energy required, to assure shallow discharges.

Follow these tips for the longest life:

• Avoid ultra-deep discharges. The definition of

ultra-deep discharge may vary with application and

battery type.

• Don’t leave a battery at a low stage of charge for an

extended length of time. Charge a discharged battery

as soon as possible.

• Don’t cycle a battery at a low state of charge without

regularly recharging fully.

• Use the highest initial charging current available (up to

30% of the 20-hour capacity per hour) while staying

within the proper temperature-compensated voltage

range.

C. Battery Capacity and Discharge Rates

Battery capacity is related to runtime at a fixed rate and tem-

perature. It has units that are the product of current multiplied

by time (such as ampere-hours). The ampere- hour is a unit

of electrical charge.

Capacity is often defined on the basis of a 20-hour runtime.

If the 20-hour capacity is 100 ampere-hours, the typical new

fully charged battery can deliver 5 amps for 20 hours at the

standard temperature (80°F) to the standard cutoff voltage

(10.50 volts under load). Reserve capacity is the minutes of

runtime under a 25-amp load.

The relationship between capacity and discharge rate is

shown by Peukert’s curve. The faster you discharge, the fewer

ampere-hours you will get. Some chargers and battery moni-

tors may request “Peukert’s coefficient”. The following graph

represents EPM AGM commercial batteries.

SAE J2185 Testing Cycling and Starting Performance

(Graph represents general criteria of this test and is not showing results of a particular battery.)

SAE J2185 Life on Various Batteries

SAE J2185 @ 158°F/ 70°C performed on DP Flooded, Standard

AGM, and Fahrenheit AGM. Elevated temperature testing to

represent rise in overall industry battery box temperatures

7.20

7.70

8.20

8.70

9.20

9.70

10.20

26 52 78 104 130 156 182 208 234 260 286 312 338 364 390 416 442 468 494 520 546 572

Voltage @ 50s Crank

Cycles

SAE J2185 @ 70C

on EPM Batteries

DP AGM Fahrenheit

Requirement

The Effects of the Speed of Discharge on

Available Capacity

Typical Peukert Relationship (EPM AGM)

Speed of Discharge Versus Available Capacity

1. Capacity varies with temperature

For cycling service, if the discharge rate is low, the reduc-

tion rate for temperature is approximately 0.5% per 1°F.

If you know the capacity at a specific discharge rate at 80°F,

you should expect approximately the following at lower

temperatures:

• 90% at 60°F • 80% at 40°F • 70% at 20°F

For starting service, the reference is to CCA at 0°F.

If you know the current the battery can support for 30

seconds at 0°F, you should expect the battery can support

the following at varying temperatures:

• 80% of that current at -20°F • 125% of that current

at 32°F • 140% of that current at 80°F

SAE J2185@122ºF/50ºC

7.2

7.7

8.2

8.7

9.2

9.7

10 .2

26 52 78 1 04 1 30 1 56 1 82 2 08 2 34 2 60 2 86 3 12 3 38 3 64 3 90 4 16 4 42 4 68 4 94 5 20 5 46 5 72 5 98 6 24 6 50 6 76 7 02 7 28 7 54

SAE J2185 @ 50C

on EPM Batteries

Star t ing Dual Purpose AGM Fahren he it

D. Vibration Resistance in an AGM Design

Vibration resistance is extremely important to battery life in

almost any application, but especially in a commercially used

vehicle and equipment that undergoes long hours of continual

use. The glass mats in AGM batteries are wrapped around the

positive plate, which helps prevent damage from vibration.

The typical vibration test for on-road trucking applications was

a test adopted from the SAE off-road work machine battery

standard. This SAE J930 Level 2 test is an 18-hour test at

5.0 peak G-force on the vertical axis at 30-36Hz. TMC RP-

125 describes the same test. This test consists of about 2.2

million upward motion reversals and 2.2 million downward

motion reversals where each reversal of direction requires the

battery to absorb a force of 5 times its own weight. Metals will

eventually break from fatigue. Holes can be rubbed through

separators or the separators can move out of position. A

battery that can survive this severe test is extremely unlikely

to suffer degradation from vibration from typical road use in

its service lifetime. East Penn’s AGM products are especially

designed to withstand the effects of vibration as seen from the

results of utilizing these vibration tests.

1. Proper mounting is important

If the battery can bounce, slide around, or if the mounting

system can flex excessively, on the road failure is possible

– even with a vibration-resistant AGM design. The vehicle

manufacturer and end user are responsible for correct

mounting. Properly mounting and/or securing each individual

battery is one of the best ways to prevent the batteries in a

system from excessive vibration and damage.

IV. TESTING CONSIDERATIONS

OF AGM DESIGNS

A. Preparing for Testing and Charging

It is important to follow all BCI (Battery Council International)

safety instructions for working around batteries, handling

batteries, and charging batteries for you and all bystanders.

1. Visually inspect each battery for damage. Do not charge or

test a damaged battery. Remove from service.

2. Inspect vehicle. Repair or replace ineffective hold-downs.

Clean connections and terminals as needed. Replace

damaged wiring.

3. Group 31 charging adapters must be used for testing and

charging batteries with stud terminals. DO NOT use battery

studs themselves for testing or charging. The adapters

must be tight against the lead “button” at the base of the

stud. Alternatively, you may clamp directly to the sides of

the lead button. Both sides of both clamps must make good

electrical contact with the lead button.

4. Be sure to use the CCA rating for a handheld tester or

calculate the load for a load tester. Other ratings are often

also displayed. Using the wrong expectations could lead to

incorrect results.

B. Evaluating the battery condition of

a charged battery

It is recommended that testing should not occur until at least

4 hours have passed since the battery was charged. Resting

the battery minimizes the occurrence of good batteries being

called “bad” and bad batteries being called “good.” The battery

must be disconnected. (Some chargers continue supplying

a maintenance charge while indicating, “done.”) A handheld

conductance tester’s accuracy can be diminished when testing

a battery that was recently charged. Resting also gives a better

indication of battery shorts.

C. Testing options

• BCI load test—Using a carbon pile or similar discharging

device, load the battery at 1/2 of the CCA rating. Note voltage

at 15 seconds and stop discharge. If voltage is less than 9.6

(normal temperature of 70°F), replace battery.

• Fixed load test—Similar to BCI test except voltage limit de-

pends on CCA rating. See instructions or meter for details.

If tester can do both 6-volt and 12-volt batteries, be careful

of 12-volt batteries that fall into the “good” 6- volt battery

range. These are bad.

• Handheld conductance tester—Since AGM and Gel

batteries have lower internal resistance than traditional

lead acid batteries, they require electronic testers that are

programmed specifically for them. Many older-model bat-

tery testers cannot adequately test AGM and Gel batteries.

D. BCI and Fixed Load Test Procedure

PROPOSITION 65 WARNING: Battery posts, terminals and related accessories contain

lead and lead compounds, chemicals known to the State of California to cause cancer

and reproductive harm. Batteries also contain other chemicals known to the State of

California to cause cancer. WASH HANDS AFTER HANDLING.

% CHARGE

OPEN CIRCUIT VOLTAGE

VRLA

100 12.8 or higher

75 12.60

50 12.30

25 12.00

0 11.80

1. Recharge if the OCV is below 75% state of charge (Refer to the chart above).

Use a voltmeter to determine the OCV.

2. If you have an adjustable load meter, set the load for 1/2 the CCA rating.

3. Apply the load for 15 seconds. Battery should maintain a voltage greater

than 9.6 volts at 70°F while load is applied.

4. If below 9.6 volts at 70°F, recharge and repeat test.

5. If below 9.6 at 70°F volts a second time, condemn and replace the battery.

V. CHARGING CONSIDERATIONS

OF AGM DESIGNS

In the rare occurrence that an AGM battery needs to be

charged outside of the vehicle’s charging system, there are

numerous chargers that can be used. Many common battery

chargers are not fully compatible with AGM batteries; how-

ever, if the voltage does not exceed 15.4 volts at any time,

they will not harm the battery if used only once or twice

over the battery’s lifetime.

Adversely, not all chargers are compatible. Some can produce

severe battery damage in only a few hours of use. Large

“wheeled chargers” that are found in many shops must be

avoided unless a 15.4 voltage limit is maintained.

SEE SPECIAL AGM CHARGING NOTE ON PAGE 3.

A. Ideal Charging Parameters

East Penn recommends the following charging parameters

be used for its AGM product to optimize the battery’s

performance and life:

• Charge/Absorption/Equalize Between

13.8 – 14.6 Volts @ 77°F (25°C)

• Float/Standby Between 13.4 – 13.6 Volts @ 77°F (25°C)

• Temperature Corrected Charging Required

B. Verify that a charger/setting is acceptable:

Avoid high voltage. If there are multiple settings on a charger,

each setting must be evaluated separately.

• Check voltage a few minutes after charging begins and peri-

odically during charging. As the battery charges, the current

will fall, and the voltage may rise. It must not exceed 15.4

volts (please note: this voltage limits falls outside of the rec-

ommended charging parameters but should not damage the

battery if the battery only has to be recharged outside of the

vehicle’s voltage-regulated system a few times.)

• If a charger/setting has been verified to not exceed 15.4 volts

to a low current, the charger/setting is acceptable. (You don’t

need to watch the voltage every time.)

C. Determining Required Charging

Time of AGM Batteries

*OCV (open-circuit voltage) may be elevated by recent charging activity or

depressed by recent discharging activity. This affects the accuracy of the SOC

(state of charge) estimate.

The Typical Charging Time for Single Battery chart is

designed to give approximate times for charging and should

not be the deciding factor as to whether the battery is

finished charging. An automatic charger compatible with

the battery will look at how the voltage and/or current

varies over time to determine the battery's state of charge.

If charging is stopped prematurely, the battery will appear

to be fully charged; however, this is just the elevated voltage

from the recent charging activity. A much longer charging

time than shown will not harm the batteries if using an

appropriate voltage regulated charger.

The required charging time is often much longer than most

people realize. Electrical Charge is measured in ampere-hours

(Ah). A typical Group 31 battery holds 85 to 105 ampere-hours

from “full” to “empty” (This is the 20-hour capacity rating). An

over-discharged battery is less than empty. Charging is never

100% efficient. You normally need to add an extra 8-15% be-

yond what was removed.

1. Determine if the battery is half-discharged,

fully-discharged, or over-discharged

a. Example: an 85-ampere-hour battery, totally discharged:

you need to supply 85Ah x (100% discharged) x (115%

efficiency factor) = 97.75Ah. You need to supply about

100Ah to recharge completely.

b. To supply 100Ah, you could supply 5 amps for 20 hours,

10 amps for 10 hours, 20 amps for 5 hours, etc.

A charger does not deliver its maximum current the whole

time. When the battery approaches full charge, the charger

limits the voltage by reducing the current. Consequently, a full

charge takes about 3.5 more hours than the calculation above

suggests.

With an automatic charger, charge until the charger indicates

that charging is complete. If you are attempting to charge an

over-discharged battery, review the next section.

D. Handling Problems with Automatic Chargers

and Over-Discharged Batteries

(Note: These issues and solutions are not strictly limited to

VRLA designs)

1. Issues

• 12-volt batteries should never be discharged to less than

10.5 volts under load. Batteries as low as zero volts can often

be recharged and be acceptable for returning to service.

• To prevent sparking and avoid problems associated with

reversed hookups, many charger leads will not function until

the charger senses a minimum voltage. If the voltage is too

low, the charger will never turn on and no charging will ever

occur.

• An automatic charger is expecting current acceptance to

fall to a low value as the battery approaches a full state of

charge. An over-discharged battery may have very low initial

current acceptance. This can fool the charger into thinking

the battery is “full”. The charger will often indicate “full” and

reduce the charging voltage to a subsistence level that will be

ineffective.

2. Solutions

• Charge the battery on a wheel charger. Charge until the cur-

rent has a reading above zero. Then charge 10 to 20 minutes

(at the most) longer. Return battery to an automatic charger.

TYPICAL CHARGING TIME (HOURS) FOR SINGLE BATTERY

OCV SOC

CHARGERS MAXIMUM RATE

30 AMPS 20 AMPS 10 AMPS

12.80 100% 0.0 0.0 0.0

12.60 75% 0.9 1.3 2.5

12.30 50% 1.9 2.7 5.1

12.00 25% 2.9 4.3 7.8

11.80 0% 4.0 5.7 10.7

1. Recharge if the OCV is below 75% state of charge (Refer to the chart

above). Use a voltmeter to determine the OCV.

2. If you have an adjustable load meter, set the load for 1/2 the CCA rating.

3. Apply the load for 15 seconds. Battery should maintain a voltage greater

than 9.6 volts at 70°F while load is applied.

4. If below 9.6 volts at 70°F, recharge and repeat test.

5. If below 9.6 at 70°F volts a second time, condemn and replace the battery.

Avoid extended charging beyond 20-minutes as it could

cause permanent damage to a Valve-Regulated product.

• If the OCV is below the limit of the automtic charger, you

may need to charge the battery with a second good battery

connected in parallel. The second battery should be at least

a little discharged so that it is not also seen as being “full”

almost right away.

E. Avoid both Under-charging

and Over-charging

In many respects, under-charging is as harmful as over-

charging. Keeping a battery in an under-charged condition

allows the positive grids to corrode and the plates to shed,

dramatically shortening life. Also, an under-charged battery

must work harder than a fully-charged battery, which con-

tributes to short life as well. An under-charged battery has

a greatly reduced capacity. It may easily be inadvertently

over-discharged and eventually damaged.

Both are very prevalent in today’s commercial truck. More

auxiliary and “hotel” loads are deeply draining the battery

causing batteries to not always return to a healthy state-of-

charge. Over-charging has become extremely prevalent due

to increasing battery box temperatures causing batteries

to over-charge. It is hard to prevent over-charging due to

high temperatures, but batteries can be designed, like the

Fahrenheit, to protect against it.

VI. COMMERCIAL BATTERY SYSTEMS

East Penn has developed the ultimate AGM and Gel battery

technology to deliver both starting and accessory power. In

conjunction with a Low Voltage Disconnect, these batteries

provide the most powerful, reliable, versatile, and efficient

power solutions in the commercial industry.

A. Traditional Battery Systems

A Traditional System is comprised of two to four batteries

with sufficient total CCAs to meet engine starting require-

ments. If the vehicle has significant hotel or other key-off

loads, cycling batteries (dual purpose) are needed for good

life as well as sufficient CCAs. An automatic LVD (Low

Voltage Disconnect) is recommended for starting reliability

and battery protection where key-off loads may not leave

sufficient power for starting. The alternator ultimately

generates all the electrical energy used by the vehicle. The

alternator must be large enough to restore the energy used

from the batteries in a typical day’s running period.

B. Advanced Battery Systems

An Advanced System is needed where key-off electrical energy

needs are high. A pack of auxiliary batteries is added to support

these additional demands. Since these batteries are not used

for cranking, they can be discharged more deeply. Since loads

can be removed from the starting pack, the starting battery pack

can be optimized for the starting duty. An automatic switch joins

the packs for charging. The charging system(s) must be large

enough to handle the total energy needs in the time available.

LVDs are needed for battery protection if not part of the auxiliary

loads. The following illustration shows how an electrical system

utilizes an automatic switch in its design.

C. The Use of a Low Voltage Disconnect (LVD)

LVDs are typically found in sleeper cab applications. The LVD

limits discharging by hotel loads so that you can start the

next day. They have a fixed set point typically between 11.7

and 12.1 volts. Unlike a standard life cycle, since loads and

temperatures vary, an LVD does not shut off at a consistent

depth-of-discharge. The State Of Charge (SOC) at a particular

voltage depends on discharge rate and temperature. An LVD

can be progressive, shutting down less critical loads first. If

the discharge is continued this will produce a lower SOC than

a single step with the same final voltage setting. An LVD must

not shut down safety-related loads so significant loads can

continue after the last stage of the LVD is triggered.

D. The Use of an Inverter

An inverter can turn 12V DC battery power into 120V AC power

normally found in homes. The load on the batteries is deter-

mined by the size of the 120V loads being operated. This can

be much less than the watt rating of the inverter. Inverters have

some inefficiency. They may draw some power continuously

when the connected load is zero. They lose 10-15% or more in

the conversion process. The vehicle manufacturer’s recommen-

dations should be followed when installing inverters. An inverter

typically has a built-in LVD. The set point is typically not appro-

priate if the same batteries are used for engine starting.

East Penn Manufacturing Co. Lyon Station, PA 19536-0147 Phone: 610-682-6361 Fax: 610-682-4781 www.eastpennmanufacturing.com

All data subject to change without notice. No part of this document may be copied or

reproduced, electronically or mechanically, without written permission from the company.

VII. ENVIRONMENTAL TEMPERATURES

AND VENTING CONDITIONS

A. High Temperature Environments

High temperature accelerates aging and other forms of deg-

radation. You should avoid exhaust systems, radiators and

other sources of heat. The battery can also generate heat

internally. To dissipate this heat, there should be good airflow

through the battery box and space should be left between the

batteries. The ideal charging voltage varies with temperature,

but most vehicle charging systems deliver the same voltage

at any battery temperature. According to SAE J930, battery

temperatures should not exceed 52°C (125°F) during normal

machine operation.

Since 2011, high temperature environments can no longer be

avoided in class 6-8 trucks. In most cases, trucks with routes

in North America will exceed normal machine operation

temperatures. This can be detrimental to the performance of

AGM batteries built without heat protection. Flooded batteries

have some tolerance to heat because of their free-flowing

electrolyte; however, it can be very detrimental should the

battery dry out and the electrolyte levels go too low.

B. Venting Conditions

Lead batteries, including valve-regulated types, emit

hydrogen during normal use. The rate can become quite

high in an overcharging situation. The batteries must not

be charged in a sealed container to prevent hydrogen from

reaching a flammable concentration within the container.

These potentially explosive gasses must be allowed to vent

to the atmosphere and must never be trapped in a sealed

battery box or tightly enclosed space!

Some vehicle makers are installing AGM batteries in the cabin.

The minimum airflow needed to maintain a safe hydrogen

concentration for AGM batteries is not very high. Cabins are

not hermetically sealed; however, they do vary in terms of

venting requirements and air flow in each individual cabin type

should be taken into consideration. Most vehicle makers have

chosen to add a tube to direct any vented gasses directly out-

side. Make sure the vent tube in not kinked or blocked during

installation or operation.

VIII. SAFETY PRECAUTIONS FOR AGM

BATTERIES

Although all AGM batteries have the electrolyte immobilized

within the cell, the electrical hazard associated with batteries

still exists. Work performed on these batteries should be

done with the tools and the protective equipment listed

below. AGM battery installations should be supervised by per-

sonnel familiar with batteries and battery safety precautions.

A. Protective Equipment

To assure safe battery handling, installation and maintenance,

the following protection equipment should be used:

• Safety glasses or face shield (Consult application specific

requirements)

• Acid-resistant gloves

• Protective aprons and safety shoes

• Proper lifting devices

• Properly insulated tools

B. Procedures

Consult user manual of specific application for safety &

operating requirements. The following safety procedures

should be followed during installation: (Always wear safety

glasses or face shield.)

1. These batteries are sealed and contain no free-flowing

electrolyte. Under normal operating conditions, they

do not present any acid danger. However, if the battery

jar, case, or cover is damaged, acid could be present.

Sulfuric acid is harmful to the skin and eyes. Flush

affected area with water immediately and consult a

physician if splashed in the eyes. Consult MSDS for

additional precautions and first aid measures.

2. Prohibit smoking and open flames and avoid arcing in

the immediate vicinity of the battery.

3. Do not wear metallic objects, such as jewelry, while

working on batteries. Do not store un-insulated tools in

pockets or tool belt while working in vicinity of battery.

4. Keep the top of the battery dry and clear of all tools and

other foreign objects.

5. Provide adequate ventilation and follow recommended

charging voltages.

6. Extinguishing media: Dry chemical, CO

, water and foam

extinguishers.

7. Never remove or tamper with pressure-relief valves.

Warranty void if vent valve is removed.