MK Battery Manual
The valves only let gas out, never in. A partial vacuum can form
within a sealed battery under various circumstances. Battery temper-
ature and ambient pressure play a role, but predominantly the
recombination and discharge reactions are responsible. After charging
ends, the recombination reaction continues until most of the oxygen
in the battery headspace is consumed. The total volume of the battery
components decreases slightly during a discharge. Deeply discharged
batteries often have a “sucked-in” appearance. Batteries with large
cells may display this appearance even when fully charged.
If a battery bulges severely on charge, this is not normal. It is an
indication of a blocked valve or an overcharge situation. Such a
battery should be removed from service.
A sucked-in appearance can also be normal. A sucked-in battery
should be charged, but if it remains sucked-in after charging, the
appearance can safely be ignored; however, if only a single cell
displays or lacks this appearance a load test would be prudent.
How safe are VRLA batteries?
Can they explode?
VRLA batteries are very safe, unless abused. However, as with any
type battery, certain safety precautions must be taken.
ALWAYS WEAR SAFETY GLASSES
WHEN WORKING AROUND BATTERIES!
CALIFORNIA PROPOSITION 65 WARNING: Batteries, battery posts,
terminals and related accessories contain lead and lead compounds
and other chemicals known to the state of California to cause cancer
and birth defects or other reproductive harm. Wash hands after
handling.
Because VRLA batteries normally emit very little to no hydrogen gas,
they are safe near sensitive electronic equipment. They do not
cause corrosion of surrounding metals. No hydrogen gas means
no dangerous explosions… UNLESS SEVERELY OVERCHARGED!
Do not install any lead-acid battery in a sealed container or enclo-
sure. Hydrogen gas from overcharging must be allowed to escape.
DO NOT CHARGE IN EXCESS OF 14.1V @ 68°F - Gel Cells
DO NOT CHARGE IN EXCESS OF 14.6V @ 68°F - Absorbed
Always use a reliable, temperature-sensing, voltage-regulated,
automatic charger.
Because SVR batteries have immobilized electrolyte, they cannot
spill or leak, even if punctured. That is why they are approved for air
transport by the International Commercial Airline Organization (ICAO),
International Airline Transport Association (IATA), and Department of
Transportation (DOT) as noted on the label if properly insulated from
short circuits.
14
e. At the end of charge (when the current is very low or goes
to zero) check and record the voltage. Note that the charger
may have turned off by then.
f. The disconnected battery should be at 100% or above after a
24 hour rest.
During the charging time, the charger should not have exceeded
the limit (except for occasional, brief pulses). This indicates that
the charger is working properly.
Keep in mind that the voltage limit is at 68°F/20°C. Charging at
higher or lower temperatures will change this limit.
A temperature-sensing charger should always be used, as
manual adjustments are never accurate and will damage any
VRLA battery.
Do VRLA batteries have a
“memory” like ni-cad batteries?
One of the major disadvantages of nickel-cadmium (ni-cad)
batteries is that after shallow discharge cycles, the unused portions
of the electrodes “remember” the previous cycles and are unable
to sustain the required discharge voltage beyond the depth of the
previous cycles. The capacity is lost and can only be restored by
slowly discharging completely (generally outside the application),
and properly recharging. VRLA batteries do not exhibit this
“use it” or “lose it” capacity robbing effect known as memory.
What is a safe charge rate or voltage
setting for outdoor applications with wide
temperature fluctuations if a temperature-
sensing charger is not available?
NONE! As the chart on page 11 (Effect of Temperature on
Recharge Voltage) shows, charging voltage varies widely with
temperature. There is no fixed voltage setting or current that
will work. A temperature-sensing, voltage-regulated charger
must be used. Anything else will damage any battery and cause
premature failure!
Can a VRLA battery be load tested?
Yes. See page 13 (How can you tell if a VRLA battery has been
damaged by under- or overcharging?).
Why do some VRLA batteries bulge?
Why do some VRLA batteries appear
“sucked in”? Are there visual signs of a
faulty or plugged pressure relief valve?
To prevent the permanent loss of gases so that recombination
has time to take place, each cell can hold up to about 1.5 psi
without venting.
Batteries with very large cells, such as the 8G4D, 8G8D, 8A4D, 8A8D
and 8GGC2, will bulge somewhat as this normal pressure builds. This
is especially true in higher temperatures, because the polypropylene
case is pliable. Therefore, a certain amount of bulge is normal.
DANGER
/
POISON
!
KEEP OUT OF THE REACH OF CHILDREN.
DO NOT TIP. KEEP VENT CAPS TIGHT AND LEVEL.
DO NOT OPEN FLUSH COVER BATTERIES.
SHIELD
EYES.
EXPLOSIVE
GASES
CAN
CAUSE BLINDNESS
OR INJURY.
NO
•
SPARKS
•
FLAMES
•
SMOKING
SULFURIC
ACID
CAN CAUSE
BLINDNESS OR
SEVERE BURNS.
FLUSH EYES
IMMEDIATELY
WITH WATER.
GET
MEDICAL
HELP
FAST.
KEEP OUT OF REACH OF CHILDREN.
DO NOT OPEN BATTERIES.