3. Battery: examination and maintenance
- Details of the regular checks needed to maintain the battery in good condition are given in
Routine Maintenance, together with instructions on removal and refitting and general battery care.
Batteries can be dangerous if mishandled; read carefully the 'Safety First'
section at the front of this Manual before starting work, and always wear overalls or old clothing in case of accidental acid spillage.
If acid is ever allowed to splash into your eyes or on to your skin, flush it away with copieus quantities of fresh water and seek
medical advice immediately.
- When new, the battery is filled with an electrolyte of dilute sulphuric acid having a specific gravity
of 1.280 at 20°C (68°F). Subsequent evaporation, which occurs in normal use, can be compensated for by topping up with
distilled or demineralised water only. Never use tap water as a substitute and do not add fresh electrolyte unless spillage
- The state of charge of a battery can be checked using an hydrometer.
- The normal charge rate for a battery is 1/10 of its rated capacity, thus for a 14 ampere hour unit
charging should take place at 1.4 amp. Exceeding this figure can cause the battery to overheat, buckling the plates and
rendering it useless. Few owners will have access to an expensive current controlled charger, sa if a normal domestic
charger is used check that after a possible initial! peak, the charge rate falls to a safe level. If the battery becomes hot
during charging stop. Further charging will cause damage. Note that cell caps should be loosened and vents unobstructed
during charging to avoid a build-up of pressure and risk of explosion.
- After charging top up with distilled water as required, then check the specific gravity and battery
voltage. Specific gravity should be above 1 .270 and a sound, fully charged battery should produce 15 - 16 volts, If the
recharged battery discharges rapidly if left disconnected it is likely that an internal short caused by physical damage or
sulphation has occurred. A new battery will be required. A sound item will tend to lose its charge at about 1 % per day.