Generator & Battery Bank Loading
Generator & Battery Bank Loading
(OP)
I've heard it commonly said that 80% is the maximum loading on generators and battery banks. However, I'm not seeing this in the NEC (Arts. 110,300,445,480,700,and 701). Is maximum loading capacity a manufacturer standard? I've got fluorescent & HID lighting loads to back up on both sources.
(The generator is 30 years old.) --- Thanks
(The generator is 30 years old.) --- Thanks






RE: Generator & Battery Bank Loading
beware restrike charactersitcs and cold/wet stacking
ethical/legal implication of succesfully operating system
life safety outside NFPA 70
RE: Generator & Battery Bank Loading
Also, you mention that you have lighting that you are trying to back up with both sources. If you are trying to support a UPS from a generator, be careful. UPS systems often have a leading power factor, which can mess badly with the generator governor. Some newer UPS designs avoid this. However, with some generator and UPS combinations, the total UPS load on the generator cannot exceed 50 or 60%.
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
however, operating at 100% loading will make heavy demands on engine oil longivity and fuel economy.
IF YOU ARE GOING BY THE POWER RATING SPECIFIED ON THE ALTERNATOR CASING it may be a wise idea to run at slightly less than 100% as the engine power output may be rated at the same value as the alternator output ( 1 horse power is approx 750 Watts). as the efficiancy of the alternater is typically 80% you may overload the engine. hope this helps.
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
The rated capacity is linked to a given discharge-time, eg 5h, 10h, 20h. The longer the discharge-time, the higher is the rated capacity of the same battery.
In general it's not wise to take out more than 80% of the available capacity of a lead-acid-battery, because of the risk of deep-discharge. Deep-discharge will damage the battery.
The NiCd-battery is more robust against deep-discharge.
RE: Generator & Battery Bank Loading
What type of generator are we talking about here? Note that
///regulated\\\
utility generators are normally operated at 100% of rating on base load.
///The "supervised" deregulated utility may somewhat change the loading pattern.\\\
RE: Generator & Battery Bank Loading
I believe that the principle of economic dispatch will continue to govern the reality of power system operations. A utility will operate its most efficient units at base load before bringing on lower ranked units to meet system demand. This will result in the more efficient units being operated continuously at their design loading.
Of course, small systems may have different objectives. An example would be a cogeneration plant whose mission is to optimize thermal loads rather than electrical, or which has a mandate to supply in-house loads only, without exporting power to an interconnected utility grid. Either of these scenarios could result in the generator being operated at less than rated load.
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading
jbartos -
I believe that the principle of economic dispatch will continue to govern the reality of power system operations.
///Yes, this is true. However, what the principle of economic dispatch includes appears to be changing. The contractually committed power has to be delivered or the penalty is imposed. This means that the power generating plant may need to have some spare capacity available for cover the load fluctuations to avoid penalties. One way to be prepared for the load fluctuations is to have a generator running at less than 100% (or 110% or so, if a temporary and short peak is encountered).\\\
RE: Generator & Battery Bank Loading
RE: Generator & Battery Bank Loading