Battery; Precautions; Charging A Discharged Battery - Mercury 225 EFI Service Manual

Battery

Precautions

If battery acid comes in contact with skin or eyes, wash skin immediately with a
mild soap. Flush eyes with water immediately and see a doctor.
When charging batteries, an explosive gas mixture forms in each cell. Part of this gas es-
capes through holes in vent plugs and may form an explosive atmosphere around battery
if ventilation is poor. This explosive gas may remain in or around battery for several hours
after it has been charged. Sparks or flames can ignite this gas and cause an internal ex-
plosion which may shatter the battery.
The following precautions should be observed to prevent an explosion.
1. DO NOT smoke near batteries being charged or which have been charged very re-
cently.
2. DO NOT break live circuits at terminals of batteries because a spark usually occurs
at the point where a live circuit is broken. Always be careful when connecting or dis-
connecting cable clamps on chargers. Poor connections are a common cause of elec-
trical arcs which cause explosions.
3. DO NOT reverse polarity of battery terminal to cable connections.

Charging a Discharged Battery

Hydrogen and oxygen gases are produced during normal battery operation or
charging. Sparks or flame can cause this mixture to ignite and explode, if they are
brought near the vent openings. Sulphuric acid in battery can cause serious
burns, if spilled on skin or in eyes. Flush or wash away immediately with clear
water.
The following basic rule applies to any battery charging situation:
1. Any battery may be charged at any rate (in amperes) or as long as spewing of electro-
lyte (from violent gassing) does not occur and for as long as electrolyte temperature
does not exceed 125 F (52 C). If spewing of electrolyte occurs, or if electrolyte tem-
perature exceeds 125 F, charging rate (in amperes) must be reduced or temporarily
halted to avoid damage to the battery.
2. Battery is fully charged when, over a 2-hour period at a low charging rate (in amperes),
all cells are gassing freely (not spewing liquid electrolyte), and no change in specific
gravity occurs. Full charge specific gravity is 1.260-1.275, corrected for electrolyte
temperature with electrolyte level at 3/16 in. (4.8 mm) over plate, unless electrolyte
loss has occurred (from age or over-filling) in which case specific gravity reading will
be lower. For most satisfactory charging, lower charging rates in amperes are recom-
mended.
3. If, after prolonged charging, specific gravity of at least 1.230 on all cells cannot be
reached, battery is not in optimum condition and will not provide optimum perform-
ance; however, it may continue to provide additional service, if it has performed satis-
factorily in the past.
90-884294 OCTOBER 2001
CHARGING & STARTING SYSTEM
CAUTION
WARNING
Page 2B-5