ELECTRICAL SECTION 8
Page 37
DRESSTA TD-25M EXTRA
BATTERY
d. Charging Low Water Loss Batteries
Refer to SAFETY PRECAUTIONS. If, when charging the battery, violent gassing or spewing
of electrolyte occurs, or the battery case feels hot 52 [°C], reduce or temporarily halt charging
to avoid damaging the battery. For best results, batteries should be charged while the electrolyte
is at room temperature 13 - 30 [°C]. Since age, state of charge of batteries vary. Time and
attention must be given to batteries during any charging process.
The charge a battery is equal to the charge rate in amperes multiplied by the time in hours. Thus
a five ampere rate applied to a battery for ten hours would be a 50 ampere-hour charge to the
battery. To fully recharge a battery, you must replace the ampere-hours or ampere-minutes
removed from it: plus an extra 20 [%] charge.
14. BATTERY CHARGING GUIDE
Recommended Rate and Time for Fully Discharged Condition
Rated Battery Capacity Charge
Above 126 to 170 Minutes 2.75 hours at 30 Amperes 3 hours at 25 Amperes
4 hours at 20 Amperes 5.5 hours at 15 Amperes
Determine the state-of-charge of the battery with a hydrometer or open circuit voltmeter. The best
method of making certain a battery is fully charged, is to measure the specific gravity of a cell once
per hour. The battery is fully charged when the cells are gassing freely at low charging rate and
less than 0.003 change in specific gravity occurs over a three hour period.
When any battery is being charged, periodically measure the temperature of the electrolyte, if the
temperature exceeds 52 [°C], or if violent gassing or spewing of electrolyte occurs, the charging
rate must be reduced or temporarily halted.
The battery generally cannot be fully charged the fast charge method. But it will receive sufficient
charge (70 to 90 [%]) for practical service. To completely recharge a battery, follow the fast charge
with a slow charge until to change in specific gravity occurs over a three hour period.
A battery with electrolyte specific gravity of 1.225 or above, should never be charged at a high rate.
If the battery is badly sulfated, the temperature may rise rapidly soon after it is placed on charge.
As the sulfate starts to break up, the charge rate in amperes will increase noticeably. These
batteries should be placed on a slow charge. If a battery is to be recharged overnight
(16 hours), a timer or voltage controlled charger is recommended. If a battery cannot be restored to
a fully charged condition by slow charging, it should be rejected. The slow charge conditions are
above in Battery Charging Guide. The temperature of a normal battery may rise above the desired
maximum of 52 [°C] if it reaches the fully charged state and is left on charge.
15. BATTERY STORAGE
Low water loss batteries have excellent shelf life due to their low self-discharge rates. Batteries
should be stored in a cool, dry place. Storage above 27 [°C] increases self-discharge. If batteries
are discharged, the electrolyte may freeze when stored below -7 [°C].
Battery stock must be rotated on a strict "first-in, first-out" basis.
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