Solving the Problems of the Cartier
Page 21
Page 22
Page 25
If you've noticed an error in this article please click here to report it so we can fix it.
The Electric as a Haulier's Vehicle
The Pros and Cons of the Battery-electric Vehicle Considered from the Point of View of a Haulage Contractor ; the Work it is Suitable for und its Cost of Operation
IHAVE had an inquiry from a haulier which is of, an unusual nature. He is interested in the electric vehicle and asks me to give him some comparative figures of operating costs for horse-drawn, petrol and electric vehicles. The inquiry runs; "I am interested in milk deliveries .within a radius of, say, 20 miles and I should like to have technical and expert advice on the operation of a 25-cwt. electric vehicle, a one-horsed vehicle and a 25-cwt. petrol vehicle,"
I am taking the trouble to enlarge upon the problen. because, in the near future, I think the information is quite likely to be of interest' to other hauliers.
The electric vehicle can be usefully employed to handle certain traffics, It is economical and advantageous in house-to-house deliveries of coal, milk, bread, laundry, as well as in local deliveries from shops and general stores,
and in the haulage of beer. In all cases, however, its utility is determined and limited by the conditions a operation. It is most essential that those limitations be fully understood, otherwise the operator and the reputation of the electric vehicle are going to suffer,
In my reply to the inquirer I dealt only with costs of operation, leaving the broader aspects of the comparison— too much to deal with in a letter—for _consideration in this article. • The first point that I made in reply was that, as he was. proposing to carry milk up to a radius of 20 miles, he would probably require to do more than 40 miles per day. In my opinion, he would not be able to do that seven days per 'week with only one horse.. He would need, as it were, relays of horses, and would have to have at least three animals to be able to do the job.
Operating Costs for Horses and Motors
Under those conditions, the costs for the horsed vehicle would, I told him, be as follow:—For horses good enough for the work be would probably have to pay £80 each, which is £240 for the three. He would need two sets of harness at, say, £15 a set, making £30;. his van would probably cost him £80, so that his total initial outlay would be £350;
His weekly costs would approximate to the following:— Wages, £4 9s.; rent and rates; 15s.; insurance, 4s.; interest on capital outlay, 6s.; food and bedding, £3; wages of stableman (part-time), £1 is.; shoeing, 10s.; van and harness maintenance, 8s.; depreciation (horse), five years, £1; harness and van, 15 years, 4s.; food; 3s. The total is thus, £12 per week, and as his weekly mileage would approximate to 300 the cost per mile would be about 10d.
For the mechanically driven vehicles, I referred him to " The Commercial Motor" Tables of Operating Costs. For a 25-cwt. machine I advised bim to take the average of the figures in those Tables for the 1-ton and li-tost vehicles. Fo'r 300 miles per week, that would mean he would have to take the average of 8.46d, and 9.45d. which is as near as makes no matter, 9d, per -"mile. For the electric vehicle the corresponding figure is 8d. per mile.
On the basis of comparison costs, therefore, the electric vehicle has it.
, Actually, of course, that is not the whole story. Before being able to assess the costs of the electric accurately it will be necessary to go more precisely into the conditions of operation. In the first plate, the daily mileage is much too near the limit of an electric vehicle fitted with, an average-size battery. It is probable, even. in flat country, that a larger battery than standard would have' to be fitted. That would increase the initial putlay and add to the cost per mile. if the district be hilly, a still larger battery will be necessary, with further additions to the cost.
Although the cost of a petrol vehicle is greater in hilly country than in flat, the difference would not be so great as that involved in this double disadvantage of high daily mileage and hilly country as it affects the electric vehicle.
Also, there is this important point to bear in mind. When the electric vehicle has completed its 40 miles or so' the limit of one charge of the battery—it has, in effect, finished for the day and cannot be used until it has been recharged, a job which takes hours. If the contract of haulage be such,that this limitation is no disadvantage and the vehicle will not be required for any further work, then the figures, .corrected as I have suggested, will stand,.
But, suppose the haulier is so placed as to be able to use the vehicle for other work during the day. Then, if he employs a petrol vehicle, not only will it be possible for him to do that extra work, impossible with the electric vehicle, but his costs will be considerably reduced. Suppose, for example, the other work means that he will be able to increase the weekly mileage with th-e petrol vehicle to 500, then the cost per mile will be not 9d. but 6id. •
A Sphere of Use for the Electric It will be appreciated from the foregoing that the conditions under which the operator is most likely to be
able to use an .electric.are those arising in connection with
a..Contract A licence, .which provides and stipulates that the work shall be for one client only. If that client wants a vehicle for a specific daily mileage, which is within the capacity of the electric, then the 'special advantage of the . petrol vehicle of being able to -do more than this daily mileage does not arise,
For the, benefit of hauliers who may have such. contracts in mind and who May, quite wisely, be considering the purchase of an electric vehicle, some further points relating to this type of machine should be emphasized.
It undoubtedly has many advantages. These, however, are so highly stressed in the publicity matter of electric vehicle manufacturers' that, so far as •I am concerned, they induce a reaction and a desire to examine the subject snore carefully. Certain 'of these advantages are incontestable.
The most outstanding, of course, is the cleanliness of the vehicle and the, ease with which it starts in the morning, provided that the battery has been fully charged during the night.
Charging is simple. The modern practice appears to be to supply a separate charger with each vehicle. Experience seems to show that on the whole, with. certain exceptions, this is the most satisfactory way of dealing With the subject. The charger is of a simple type; the most popular seems to be a rectifier embodying metal valves. This apparatus is comparatively inexpensive, practically troublefree, and is antomatic in operation, so that no attention is needed during the night.
The electric vehicle I's speedy enough for its purpose.
As a Matter of fact, high Maximum speeds are not nece:ssary for house-to-house work or local deliveries. It has been established that, when doing such work, the vehicle is stationary for 70'per cent. of the time, so that a maximum speed of 15 to 18 m.p.h., which is the usual electric-vehicle speed, is all that is necessary. It should be appreciated that the electric vehicle has good acceleration and can quickly 11;6 brought to its maximum, provided it is not hill-climbing. Often enough, in house-to-house delivery, it is not even possible to go through the gears with a petrol vehicle before it has again to be stopped, so that the much higher maximum speed of which the petrol vehicle is capable is never reached.
In this connection, the following figures, relating to the use of the three types, horsed, petrol and electric vehicles,.
over the same rounds, are of iriterest.. The work involved nearly 500 deliveries per day, with mileages approximating to 20 per day. It should be understo6d that this does not mean 500 stops, because there might be half a dozen deliveries from the vehicle each time it stops.
IVith a-horse-drawn vehicle, the maximum speed attained was 15 m.p.h, and the average working time for the complete round was 81 hours. With a petrol van, having a maximum speed of upwards of SO m.p.h., the average delivery time was actually greater, being 9i hours. Using an electric vehicle, which in this case had a maximum speed of 22 m.p.h., the delivery time was 71 hours.
When 250 Daily Deliveries Are Made
In another case, involving 250 deliveries daily and a round Vistance of 28 miles, the corresponding figures were. horsed van 9i hours, petrol van 91hours, electric van 11 hours. In a third case, with the deliveries still fewer at 100 per day and a mileage of 35, the times were: horsed van 10i hours, petrol van 9 hours, electric van 8 hours. The first of these three examples was the house-to-house delivery of milk, the second the delivery of bread, the third: laundry.
A point which advocates of the battery vehicle stress very highly is its low cost of maintenance. Reading through manufacturers' literature tine would imagine that the owner of an' electric vehicle has nothing whatever 'to do in the way of maintenance, beyond greasing, oiling, and the occasional cleaning and truing of controller and electric. motor armatures and brushes.
Experienced, users do not, appear to accept that claim at Its face value. • Here, for example, are some -comments from the director of a firm using a number of electric vehicles for milk delivery. Whilst he still continues to use electric vehicles and, therefore, presumably finds them economical for the work, he has, nevertheless, some strictures to pass in respect of this characteristic main tenance. . •
The vehicles he aces are of 12-cwt. capacity. He states that the ,principal problems of maintenance arise in connection with the .transmission and the contactor gear, and joins the two in his indictment. His experience is that the design of contactors is such that the transmission receives shocks which it is apParently not designed to withstand. He admits, however, that a .good deal depends upon the driver. The effect of these shocks is twofold. They cause trouble with the battery, due, to the fact that it is called upon for exceptionally heavy loads on occasion, and affect the transmission so much so that the -vehicles of his fleet have suffered from universal-joint breakage, collapse of crown wheel and pinion drive, and shearing of axle shafts. The maintenance of contactors, he states, depends very much on the manner of use, but they require constant attention and frequent renewal.
As regards batteries, too, it is necessary to take a few grains of salt with the claims that are made for the longevity and absence of trouble. The battery, of course, is the principal component of an electric vehicle.
It is particularly needful when selecting a battery to ensure that it is of ample capacity for the work which the vehicle is to do. There are four inter-related factors to be taken into consideration. The maximum speed which the vehicle must have in order to do the work in the time available; the nature of the country-whether the roads are good or bad, whether there are many hills,' or whether it is flat, and the-number of hills in the daily round; the number of stops per round, for the more stops and starts the greater the battery capacity necessary: and the total distance which the vehicle is to cover in its .daily round, which is the governing factor.
It is usual to claim that batteries, properly treated and maintained, have a life of 4 to 4i years. That may be so, but with the best of care and attention the battery capacity begins to fall after three years of life, so that if the battery chosen has little margin in its capaEity, then, during the latter period of its life, it will not be able to do its work arid will have to be renewed. , That is another point in favour 'of purchasing, in the first -place, a battery of ample capacity, but in my view the operator will be wise to reckon on a life of three years and no more.
Cost for the 10-20-cwt. Electric Van
Now to return again to the subject of costs, keeping
the foregoing matlers in rniiia:" .
I give, in Table I, certain figures for comparative costs Of a 10-12-cwt. van of the type most commonly employed for -milk, bread and similar deliveries. These are taken from the literature of electric-vehicle manufacturers, and as several makers use the same figures it is reasonable to assume that they come from a common source and that. I believe, was one of the periodicals devoted to matters of electrical interest.
The figures are pre-war And it may, therefore, be taken that in applying them to-day the operator should add at least 25 to 30 per cent, If it be reasonable to, add the same percentage ta all of them, then the outcome, of course, shows the electric vehicle. in an even more favourable light.
The way to deal with electric-vehicle costs is as follows. I will take as an example a 10-12-cwt.milk van, that being the most popular. type and size. The first thing to note is that all the costs, with the exception of the current for charging the battery, are standing charges. Even. the cost of tyres, which I have, hitherto, regarded As a running cost, are regarded as Standing charges by the electricvehicle experts who assess them on two years' life.
Prices are somewhat difficult to assess these days, but I
think that the following are not very wide of the mark, if they be regardell as averages:—For the chassis, £150 and the body £50—say, £60 including painting and lettering in good style. The price of the battery depends on the size or capacity and that is determined by the factors described above. For 20-miles range, the cost will approxi• mate to £90; for 30 miles £120, and for 40 miles £150. Then there is the charger, for which I propose to allow £20. The totals, which affect the interest charges, may thus be £320, £350, or £380. Interest charges are, thus, £12 16s., £14, or £15 4s. per annum. Depreciation may next be considered. The chassis can be safely given 10 years of life, so that the amount to be debited there is £15 per annum. The body cannot be expected to lust more than six years, without incurring excessive maintenance expenditure, which means a debit of £10 per annum on that account. The battery cost per annum is one-third of the initial outlay, i.e.; £30, £40, or £50 per annum. Allow £1 per annum for the charger. Thus, the total depreciation may be £56, £66, or £76. Tax and insurance, and garage rent, I will take as being £10 each. Tyres cost, to-day, £16 10s. per set, and I should think that even synthetics will last two years on an electric vehicle, so that the debit on that account is £8 Sc. per annum—£15 a year shouldcover maintenance on the average, notwithstanding what is written above on that subject.
Current consumption, as might be expected, varies, and it depends on three of the four factors already enumerated as governing the choice of a battery, i.e., on speed, nature of the district, hilly or flat, and number of stops. Assuming eight stops per mile, the consumption may be taken as being ffom one-third to one-half unit per mile. A reasonable average is 0.4. At Id. per unit, that is 0.2d. per mile; at isd. per unit it is 0.375d. per mile; at Id. per unit it is 0.5d. per mile, and so on.
Table H summarizes the above figures. They make the frequent claim that " an electric vehicle can be run for 6d. per day " look rather silly, but surely none could have believed it. S.T.R.