DEEP-CYCLE
LEAD ACID BATTERIES
THEY AREN’T GOING ANYWHERE1
THE FUTURE OF LEAD-ACID BATTERIES: NEW MARKET TRENDS
“
TRIED-AND-TESTED
battery
charging
performance
The lead-acid battery
market is gradually turning
away from the pursuit of
technology development,
to focus on the competition
of price and the stability of
the battery.
MACHINES DESIGNED
FOR PACK SIZE/WEIGHT
- Lu Xue-Long2
$
”
stability in
high-vibration
conditions
IMPROVING
PERFORMANCE
OF LEAD-ACID2
battery
safety
Global Lead-Acid Market
LOW PRICE POINT
Projected to reach
SAFE TO OPERATE
LEAD-ACID MARKET CATEGORIES2
10
US$58.5 billion by 2020 at an estimated compound annual growth rate of 4.6%
32%
58%
Electric applications (forklifts,
electric bikes, etc.)
Starter battery for automobiles and motorcycles
MOST COMMON MAINTENANCE MISTAKES BY LEAD-ACID BATTERY OWNERS
OVER
CHARGE
OVER
WATER
UNDER
CHARGE
Solution
Solution
Select the correct charge profile
Fill to the line when fully charged
PROPER MAINTENANCE FOR LEAD-ACID BATTERIES3
Water the battery at the
end of a charge cycle
2
Tips to keep batteries healthy:
Reliable, long-term
energy delivery
Can survive many
discharge cycles
Match the selected charge
profile to your battery pack
Sealed (valve-regulated lead-acid) batteries
and are considered “maintenance-free”
TYPES OF DEEP-CYCLE LEAD-ACID BATTERIES
The electrolyte can be
replenished and measured
3
Plug the machine in after
significant discharges to
prevent sulphation
AGM
FLA
GEL
(absorbed glass mat)
More forgiving of
overcharge - typical
overcharge is 100-115%
of the rated capacity.
Often used in golf and lift
truck applications.
Requires gentle charging
with a well-controlled
voltage. Often used in
personal mobility
applications.
Can withstand a high
current discharge and a
high charge rate. Often
used in floor care
applications.
(flooded lead acid)
SYSTEMATIC UNDERCHARGING
HOW DO WE KNOW?
Regular undercharging will reduce the battery
pack’s storage capacity with each recharge
cycle. Making a charge profile specific to the
battery brand and manufacturer ensures that
the battery receives a precise overcharge.
Delta-Q operates a 30+ channel
battery lab to conduct short,
medium, and long term, lead-acid
battery tests. Delta-Q services
OEMs that have the most
stringent warranty commitments.
Most 3-step or “IUI” charge profiles contain the following phases:
1. Bulk stage: using constant current (I), about 75% of the charge is returned to the
battery as quickly as possible
Voltage per cell (V)
THREE STAGE CHARGE PROFILE FOR
LEAD-ACID BATTERIES3
2. Absorption: As the battery gets full, it cannot accept energy as quickly. Applying
constant voltage (U) allows the battery to control the rate at which it accepts charge
2.7
30
2.6
25
2.5
20
2.4
15
Maintenance Phase
2.3
10
2.2
5
2.1
0
3. Finish: Provides the battery with the constant current (I) overcharge it requires to
0
2
4
6
achieve a full state of charge, at a rate that is appropriate for the size and type of
battery being charged
8
10
12
14
Current (A)
1
UNDER
WATER
16
Time
Charger DC Output Current
MAINTENANCE PHASE
Battery pack voltage per cell
EXAMPLES OF LOW DISCHARGE VS.
HIGH DISCHARGE USAGE PATTERNS3
Once the Finish Phase is complete, the battery charger goes into a
Maintenance Phase. This phase is necessary because batteries
self-discharge at up to 10% per month3.
HIGH DISCHARGE
In maintenance phase, the battery charger monitors the battery’s
level of charge over long periods of rest. When the charger detects
the battery’s level of charge is too low, it will charge the battery back
to its full state of charge to prolong the battery’s service life.
An electric scooter is used to commute 35
kilometres (the edge of its range)
A golf car is sent out for 2 rounds on a hot day
EXAMPLE OF MAINTENANCE PHASE
LOW DISCHARGE
To guard against battery discharge during the winter
months, stored golf carts are left connected to a battery
charger. The battery charger consistently monitors the
battery pack’s state of charge. When the charger
detects a low state of charge, it recharges the pack,
returning it to its optimal state of charge.
An electric pallet truck is used a couple of times
each day to move pallets over a short distance
A floor machine is used for a few minutes to
scrub the floor of a small room
RULE OF THUMB
TEMPERATURE VS. DISCHARGE CAPACITY
Temperature decreases,
battery capacity decreases8
The optimum charging temperature
for lead-acid batteries is 25.C (77.F)7
Temperature rises, battery
capacity rises8
DID YOU KNOW?
Every 8.C (15.F) rise in
temperature cuts the
battery life in half7
*not necesarily linear
DEPTH OF DISCHARGE (DOD)
C-RATINGS5
The greater the state of
discharge, the more the
battery is weakened1
To get the best
value for your
money, DOD
should not
exceed6
50%
80%
of all battery
failure is related
to sulfation
build-up4
WHAT: measurement of time it takes a battery to fully discharge
(to 1.75 volts per cell)
C-5
5 hrs to completely
discharge
C-10
10 hrs to completely
discharge
Battery specification sheets that show low C-rates, such as
C-5, are indicative of batteries for applications that have
intensive deep-cycle energy needs.
An example of C-rates for a
Trojan T-105 lead-acid battery9
C-Rating
Amp-Hour
5-Hr Rate
185
10-Hr Rate
207
20-Hr Rate
225
100-Hr Rate
250
Battery specification sheets that focus on higher C-rates, such as C-20, are
indicative of batteries specified for a “float” or less energy intensive application.
References:
RenewableEnergyWorld.com. “Lead-Acid Batteries: Merely a Launch Pad for Something Better?”
Invest in Taiwan. “Global Lead-Acid Battery Market Development Status”
Delta-Q Technologies. “Achieving ‘Charge Quality’ for Lead-Acid Batteries in Industrial...”
4
BatteryStuff.com. “Battery Basics: A Layman’s Guide to Batteries”
5
SolarHomeStead.com. “Battery AH Ratings. C5, C20, and C100. What Does This Mean?”
6
Energy Matters. “Deep Cycle Battery Voltage & State of Charge”
7
Sandia Report. “Temperature Effects on Sealed Lead-Acid Batteries and Charging Techniques...”
8
Solar-electric.com. “Deep Cycle Battery Frequently Asked Questions”
9
Trojan Battery. “Battery Specifications: 6V T-105 Deep-Cycle Flooded”
10
Future Market Insights. “Lead Acid Battery Market: Global Industry Analysis...”
1
2
3
www.delta-q.com
Further Reading
• Your Lift Truck Could Use a Drink: A Crash Course in Battery Watering
• A Guide to Understanding Battery Specifications
• Lead-Acid Batteries Here to Stay
• Lead-Acid Rules as Forklift Battery, But Alternatives Pursued
Delta-Q Technologies makes innovative industrial
battery charging solutions for all types of battery chemistries.