Section 3. Battery Service - Tecumseh HH100 Handbook

BATTERY POWER DECREASES WHILE ENGINE
CRANKING POWER REQUIREMENT
INCREASES WITH FALLING TEMPERATURE
100%
80°F
o
(26 C)
100%
46%
0°F
o
(-18 C)
250%
BATTERY CHECK. Because the battery is part of
two circuits starting, ignition and charging (in the
ignition circuit, only in switch starting units) the battery
should be checked first.
If battery has a shorted cell, overcharging can result,
and the regulator rectifier may appear to be at fault.
If a cell has an open or high resistance connection,
cranking motor operation will be affected, but replacing
the cranking motor will not cure the trouble. If the
battery is badly sulphated, consistent low gravity
readings, slow cranking, and possible poor ignition
performance can be experienced during starting.
BATTERY SIZE RATIO:
TEMPERATURE. It is always good practice to select
a replacement battery of an electrical size at least
equal to the battery originally engineered for the
vehicle by the manufacturer.
Battery power decreases while the need for engine
cranking power increases with falling temperature.
Subzero cold reduces battery capacity of a fully charged
battery to 30% of its normal power and at the same
time increases cranking load beyond the normal warm
weather load.
Hot weather will place excessive electrical loads on
batteries. Difficulty in starting may occur when cranking
is attempted shortly after a hot engine has been
turned off.
If the capacity rating for the original equipment battery
cannot be determined, a 32 amp or greater rated
replacement battery would be sufficient. IMPORTANT:
For operation at colder temperatures, a 50 amp or

SECTION 3. BATTERY SERVICE

68%
32°F
o
(0 C)
165%
30%
-20°F
o
(-30 C)
350%
AMPERAGE TO
greater rating is recommended.
BATTERY CONDITION. While the battery is built to
satisfactorily withstand the conditions under which
it will normally operate, excessive mechanical abuse
leads to early failure.
The following points are important to properly install
a battery:
1. Be sure the battery carrier is clean and that the
new battery rests level when installed.
2. Tighten the hold-down evenly until snug. Do not
draw down tight enough to distort or crack the
battery case.
3. Be sure the cables are in good condition and
the terminal clamps are CLEAN. Grease battery
terminals lightly with petroleum jelly before attaching
cable clamps. Make sure the ground cable is
CLEAN and TIGHT at the engine block or frame.
4. Check polarity to be sure battery is not reversed
with respect to the generating system.
5. Connect "ground" terminal of the battery last,
to avoid "short" circuits which will damage the
battery.
CAUTION: The charging process will chemically liberate
oxygen and hydrogen gasses. This highly flammable
mixture may be dangerous if ignited. Disconnect ground
terminal first to prevent arcing at the positive terminal.
BATTERY PRECAUTIONS. If a battery is not used
for a long period of time, it is advisable to remove
the terminal connections to prevent a slow discharge.
On some units there is an ON-OFF switch to cut
the battery out of the circuit when not in use.
Be careful when replacing battery connections. A
reversal of polarity can cause damage to the regulator-
rectifier.
BATTERY MAINTENANCE: (Acid-Type) Check water
level periodically to determine that the top of the
battery plates are covered. Never overfill !
Whenever possible, add only distilled water. If not
available, use water with the lowest possible mineral
content. Hard water will cause an accumulation of
calcium deposits.
Never add water to a battery at below freezing
temperatures unless the water has been thoroughly
mixed with electrolyte first. This may be done by
operating the engine for about 4 hours.
Do not add acid unless it has been lost. Only water
in the sulfuric acid solution is normally evaporated
through normal usage. If the solution has been lost
by spilling, add acid so there is not more than a 10
to 1 ratio of acid to water.
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