250 



ELEMENTS OF ELECTRICAL ENGINEERING. 



active material which is formed by the Plante process is more 

 compact and more firmly attached to the grids than the active 

 material that is applied to the grids mechanically in the Faure 

 process. Heavy stationary batteries usually have Plante grids, 

 and light portable batteries usually have Faure grids, or, what is 

 perhaps better, Plante positive grids and Faure negative grids. 



The following quotations from a large manufacturer give some 

 idea of the weights and costs of storage batteries : 



HEAVY STATIONARY TYPE. 



Weights and costs of a loo-volt (5o-cell) storage battery rated at 400 ampere 

 hours on an eight-hour discharge and capable therefore of delivering 40 kilowatt- 

 hours. 



Depreciation 6 or 7 per cent, per annum when properly cared for. 



LIGHT PORTABLE TYPE. 



Weights and costs of a loo-volt (5o-cell) storage battery of the carriage type 

 rated at 200 ampere-hours on a four-hour discharge and capable therefore of delivering 

 20 kilowatt-hours. 



Depreciation 15 per cent, per annum or more. 



107. Management and care of the lead storage cell.* The 

 lead storage cell deteriorates rapidly in service, especially when it 

 is not properly cared for ; and, therefore, since the first cost of a 



*The reader is referred to Chapter XIV. of Lyndon's Storage Battery Engineer- 

 ing for a very full discussion of this subject. 



