"Wet Stacking" occurs when a diesel engine operates below its rated output.  The engine begins to over-fuel or "wet stack" if there is an insufficient load to bring the engine up to operating temperature. Diesel engines are designed to operate with a load and consistently operate more efficiently in the 70% to 80% range of rated output. When a diesel engine generator operates for an extended period of time, say below 40%, over fueling occurs.

Wet-Stacking, if allowed to go on too long, can cause permanent damage should the generator be called to perform at or near peak for an extended length of time.  This potential catastrophic problem can be avoided if... read more

Question: I have an 80kW Standby Generator. The battery keeps going dry and I have to add distilled water quite often. Is this normal or should I worry?

Answer: This is not normal. It is likely that your battery is overcharging. This is usually caused by an overactive battery charger. When a battery overcharges, the fluid (sulfuric acid) begins to gas, essentially boiling the acid out of the battery. In addition to this being a maintenance concern it is also a safety issue because it increases the risk of explosion.

12 volt lead-acid batteries are typically charged to between 13.6 and 14.2 volts. However, once the battery is fully charged, it must not be maintained at this rate. A "floating charge" is usually in the range of 13.2 to 13.4 volts and is sufficient to keep the battery tip top. If your voltage is any higher than 13.6 volts, you may need a new battery charger.

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