User Manual

13
a battery, always refer to the instructions that came with the
battery charger. While maintaining a battery at its full state-of-
charge will insure optimum life, overcharging may signifi cantly
reduce it. Any of the Yuasa automatic “smart” chargers will
maintain both Conventional and AGM types of batteries without
overcharging them. Use the following guidelines for charging
AGM and Conventional batteries. Always verify battery state-
of-charge before charging, and
30 minutes after charging. a
battery charger has been disconnected from the battery for one
to two hours, a fully charged Conventional battery should read
12.6 volts (12.8 volts with Sulfate Stop) or higher. AGM batteries
may have slightly higher voltage readings after a full charge
Do Not Overcharge. Because of the characteristics of an AGM
battery, too much of a boost charge, or overcharge will decrease
the volume of electrolyte. The longer the overcharge time, the
greater the drop in electrolyte and starting power. Because the
battery is sealed, water can’t be added to make up the difference
in the loss of electrolyte. In addition, overcharging can warp
cell plates making future charging diffi cult or impossible. To
prevent over charging, track charging times carefully, or ideally,
use one of Yuasa’s Automatic Chargers. Always stop charging if
the battery case becomes too hot to touch. Let it cool down
6 to 12 hours and resume charging. Charging times will vary
depending on type of charger and the size of the battery.
Caution: Always wear safety glasses when handling
batteries and charge them in a well-ventilated area.
Charging a Deeply Discharged Battery
Batteries with an open circuit voltage below 11. 5 volts may
require a special charger and procedures to recharge. Deeply
discharged batteries will have high internal resistance, making
normal battery charging diffi cult. It may be necessary to use a
charging voltage higher than normal to get the battery to accept
a charge. The Yuasa Automatic
12V 4 Amp Battery Charger is
capable of charging at a rate of
20 volts and has two current
settings. With either charger, charge the battery for
30 minutes
and then measure the open circuit voltage. If the voltage reading
has not increased (indicating that charging has taken place) the
battery must be replaced. If the battery is accepting a charge,
continue charging. During this process the battery’s case
temperature should be checked for excessive heat. If the case
temperature becomes too high (about
140° F) charging should
be stopped or charging current should be reduced. The process
of charging a deeply discharged battery may take up to
20 hours
or more.
POINTS TO REMEMBER
■ Prolonged discharge causes harmful sulfation and may
damage a battery
■ Discharged (dead) batteries are prone to freezing in cold
temperatures
■ Short trips may not provide enough battery charging time
■ Always verify the state of charge 30 minutes after charging
■ Storing batteries in high temperatures will cause damage to
the battery
■ Never exceed 3 amps when charging a motorcycle, or other
small battery
100%
Percent of Charge (%)
Time Required to Charge (hours)
50%
75% 3-6
5-11
13-2025%
0%
Voltage (volts)
11.5 11.9 12.3 12.7 13
The approximate charging times are shown using a constant current
charger (smart charger) at the amps specifi ed on the battery.