Accumulator Propulsion in America.
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Examples of Operating Costs.
In studying the cost of operation of commercial, electrical vehicles in New York, we have been able to get the actual figures of a firm employing twelve covered delivery vans, with a load capacity of g cwt. The machines are used by a large silversmith and fancy dealer, and they are kept in the firm's private garage, current being taken from the public mains at four cents (2d.) per kilowatt hour. The average daily mileage is 22, and the maximum distance on one charge is 32 miles. It has been found that the average cost for current is $7 (28s.) per month. Thus the following can be taken as the cost for running twelve vans for one year :— In drawing up this table the cost of current has been placed at 28s. per van per month, long experience having shown that this is the average cost. Tires generally last eighteen months. Batteries are renewed at the end of one year, new plates being put in, and the old jars retained. Garage charges have been placed at ,4-3 per month per van. When the vans are kept in a public garage, the charge is
per month, all included. It is a general practice in New York to make an exclusive charge for storage room, washing, minor repairs and adjustments, and all current needed. The system of making an extra charge for current according to the amount consumed was abandoned a few years (ago, the present system, by which the van owner is entitled to as much current as he requires without any extra charge, works to the satisfaction of both parties. It is, of course, known exactly by the public garage proprietors how much current is used by the average van of a given capacity, and whatever excess there may be in the busy season is compensated for during the slack months of the year. In calculating the amount to write off for depreciation, the value of tires and batteries has been do. ducted, these being renewed every year. The complete cost of a new 9-cwt. van is £420. It will be noted that no 'account
• has been taken of interest on capital invested. It is assumed that the vans will run 310 days a year, a rather high average, and that they will average 22 miles a day; this figure is probably rather below what is actually accomplished. On this basis, the inclusive cost per mile averages to.6d. for a 9-cwt. van.
It is interesting to compare these figures with those for the same number of five-ton wagons, for this is a type distinctly American, and one for which it might be supposed that the average cost would be proportionately higher, owing to the heavy wear on rubber tires and the expense of renewing batteries. Inclusive garage charges for one of these heavy vehicles is ;613 per month. Sufficient current for ordinary work is found to cost a month, the machine averaging 18 miles a day. If the wagon were run up to its full limit, the cost for current would be probably 45. per day. Batteries have to be renewed every ten or eleven months, at a cost of .,;80 per set. In the following table the calculations have been made on a twelve-months' service. Tires, which a few years ago would not last more than eight or nine months' hard work, will now remain in service for twelve months. Attention to the suspension of the vans has lengthened their life. A complete set costs £120 :
The average price of a five-ton electric wagon is ZSoo. In calculating depreciation, the value of tires and batteries has been deducted. In making these estimates we are dealing with motors kept in a private garage, and consequently, are unable to state exactly what are the expenses for stabling. In the case of the five-ton lorries, the owner calculates ,"1,008 for current and garage charges ; if the machines were kept in a public garage, ,r,872 would have to be charged up for these two items. With the machines kept in part of a big building, one can only approximately arrive at the amount of rental.
For comparison, it is instructive to put the foregoing figures, which are the actual figures of firms which have employed electric vehicles for several years, against an estimate drawn up some time ago by Sir Hiram P. Maxim. These latter have been brought to our notice since our own estimates were obtained, and there is much to be gained by a comparison of the two. After examining each item of expenditure in detail, Sir Iliram arrives at the following table as the cost per mile of three vehicles carrying oneton, three-ton, and five-ton loads respectively.
These tables place the cost per mile considerably lower than those we first quoted. Thus the half-ton van costs to.6d. per mile compared with 6.3d. in the latter estimate ; and the five-ton lorry in one case is calculated at is. tod. per mile against is. 3d. in Sir Hiram's estimate. It will be noted, however, that in the latter estimate nothing has been charged for driving, garage, or insurance. Thus, if we add these three items to the six already accounted for, we shall be able to make a more equitable comparison. The following figures are those given by Sir Hiram as the total expenditure on one five-ton wagon for one year. To them we have added the three items which he has iwg-lected to include :-- In the Maxim estimate 5 per cent, interest on capital invested has been included, whereas this item is omitted from our own estimate. Had this been taken into account, the difference between the two costs, is. tod. per mile and 25. o.3d. per mile, would have been slightly less. It is certain proof of the value of the figures that the two sets, taken from entirely different sources, should so nearly accord.
It may be instructive to examine more in detail the figures of the Maxim estimate. The battery for the fiveton lorry under discussion has 44 cells of 19 plate MV Exide Express. This is able to manage a full day's work on one charge. Annual battery expenses work out as follow :Z s. d.
New positive plates... ... ... 48 16 New negative plates ... ... 26 6 4 2 ling ... .. ... ... ... Rubber jars 'broken in service and 9 9
in handling ... ... ... Totallabour in connection with 7 00 battery ... ... ... 20 6
Supplies and other expenses 15 o 0 4
Total ... 127 0 7 An average day's work for a five-ton wagon seems to be about 20 miles, and the total number of running days may be taken as 288. This brings the total mileage in one year to 5,760. Tires for a lorry of this size should be 7 inches on the rear wheels and 6 inches on the front road wheels. A complete set now costs about £92 I6S. As their life in average service is about 7,680 miles, the annual cost is now reduced to '69 125. 6d. The cost of current for one year on the mileage indicated is .:37 6s, 8d. General repairs are calculated an a 4 per cent. basis. Taking the price of the lorry as L:800, and deducting the value of tires and batteries, the amount to write off is .4.22 55. tod. Depreciation is allowed for on a 10 per cent, basis, and interest at 5 per cent.
To epitomise, the average cost of electric haulage in New York is 8d. to Lod. per mile for half-ton to one-ton vans; 1s. id. 10 is. 4d. per mile for three-ton wagons; and is. to 25. per mile for five-ton lorries.