Multiquip MQP45GM, MQP20IZ Mechanical Installation — Battery System, Purpose of the Battery

MECHANICAL INSTALLATION — BATTERY SYSTEM

Purpose of the Battery

The major function of the battery is to supply current to start the engine. The current required to crank the genset engine varies by model. Cranking current is dependent upon the engine stroke and bore, the number of cylinders, engine/ starter ratio, circuit resistance, temperature, engine oil viscosity, and the accessory loads. A four-cylinder engine could require as much cranking current as an eight-cylinder engine with greater displacement. All of these factors are considered when an original equipment battery is specified by the engine manufacturer.

How BatteriesWork

When two unlike materials such as the battery positive and negative plates are immersed in sulfuric acid (the electrolyte), a battery is created and a voltage is developed. The voltage developed depends on the types of materials used in the plates and the electrolyte used. Electrical energy is produced by the chemical reaction between the different materials and the electrolyte. When the chemical reaction starts, electrical energy flows from the battery as soon as there is a circuit between the battery positive and negative terminals.

Lead-acid storage battery voltage is determined by the materials used in its construction. The chemicals used are:

zLead dioxide (PbO2) — the material on the positive

zSponge lead (Pb) — the material on the negative grid

zSulfuric acid (H2SO4) — the electrolyte

The battery also supplements the DC load requirements whenever the load excess the charging system's ability to deliver the necessary power. Charging systems will carry the electrical load under normal conditions. However, if the engine is at idle speed, the battery may have to supply a portion of the accessory load. The battery must supply the genset's electrical load requirements if the charging system fails.

The battery can also act as a voltage stabilizer in the charging system. Occasionally, very high transient voltages are generated in the electrical system. This may occur in the making or breaking of a circuit in the system. The battery partially absorbs and reduces these peak voltages, thereby protecting solid-state components from damage.

MQ Power Batteries

MQ Power Industrial Gensets use heavy duty commercial grade, lead acid type, low water-loss batteries. These batteries do not need to be serviced (such as adding water), and when properly maintained only need to be replaced after the pro-rata date (usually 36 months).

Batteries are sized to meet or exceed engine manufacturer's ampere/hour starting requirements and comply with NFPA- 110 requirements for engine cycle-cranking.

LowWater-loss Batteries

A low water-loss battery is designed to relieve the consumer of routine maintenance requirements such as adding water during the service life of the battery. Low water-loss batteries produce very little gas at normal charging voltages and, therefore, the rate of water loss is very low. MQ Power battery rate of water loss is low enough that the venting systems can be completely sealed, except for small vent holes, and water additions are not necessary for the life of the battery.

The advantages of low water-loss batteries when compared to conventional batteries are:

zDo not require servicing

zDo not require activation and boost-charging prior to installation

zGreater overcharge resistance

zReduced terminal corrosion

zElimination of overfilling and possible addition of harmful impurities

When replacing a genset

battery, a battery at least

NOTEequivalent to, and preferably greater than the original battery ratings is recommended.

PAGE 50 — INDUSTRIAL GENERATOR SETS — APPLICATION & INSTALLATION MANUAL — REV. #4 (09/07/07)