I second Tennessee's notion. I just reviewed the LD Bailey 'white paper', and whether it was or not, it definitely read like it was written as an intentional advocacy for IC truck suppliers.

While there are several questionable points of data (maintenance costs, battery washer costs, etc, battery life cycle), the most inaccurate cost I saw was, indeed, the per hour kWh cost of the battery driven truck (I will give them a pass on the LPG tank costs, assuming a bit of a dated evaluation).

LD Bailey correctly indicated that they measured consumption from a less efficient system, versus that which is on the market today, but to claim (if I understand that claim correctly), that an electric truck uses over 23 kWh per hour is not accurate (for example, I would like to see what else is going on during the high peak times, for example). A typical 5k capacity electric forklift battery may have approximately a 40 kWh capacity. At full discharge, one must return 32 kWh back to that battery, given a 'full discharge' being equivalent to an 80% discharge (80% - or 32 kWh). Assuming from the study 6 hours of use per cycle, that would mean that it takes 141 kWh of electricity to return 32 kWh back to the battery, or something like a 23% level of efficiency (almost 80% of the input electricity is lost during the charge. Even in the least efficient charging systems from days past, that is way off base.

Don't get me wrong, I have seen several 'studies' that just give an equivalent transfer charging cost equation (if I need to return 32 kWh to my battery, it must cost 32 kWh to do so, or at 8.8 cents per kWh, or about $2.82). That is definitely not a fair assessment, either. There are going to be losses during a charge, even with the most efficient systems. However, the efficiency will still be over 50%.

Anyway, that's enough on that from me.

The L.D. Bailey report is greatly inaccurate. Attributing extra electric usage for the whole plant to extra hrs on a forklift would not be near as accurate as measuring the power used by the chargers. The bailey report also estimates that batteries will only last three years and that lp gas is only $1.35 per gallon or about $10 a tank. Maintenance costs were estimated on the lp unit at $420 per month and on the electric at $350 per month (3000hrs @5yrs) also greatly skewed. It would be nice to see a more accurate comparison. ITA numbers show the market continuing to move more toward electrics and that will likely accelerate as battery/charger technology improves.

in my humble opinion. all these numbers are just about (edumacted) W.A.G.s, since none are calculating the full_ wattage_ used during the full charge-cooldown-use cycle, (not just 1 hour of charge, which as we all know can very greatly depending on state of charge) heat loss during charge, the fact it takes more than 1 watt of electric power at the (A-C) wall socket to charge the battery so that it outputs (D-C) 1 watt at the lift motor, we are also calculating the amount of watts put into a battery based on it's voltage loss (apples and oranges) and not watts output.
Nor are we including in the numbers the advantage of no idle motor running time in an electric -vs- how much an LPG unit uses just sitting waiting.
We are also promulgating the false notion of a lead acid battery having only so many cycles. This is an over simplification used to explain to (supposedly clueless) operators why short charging is bad, (without explaining how an industrial battery differs from their car's lead acid battery that can recharge every time they start the car), not a design feature in forklift/ industrial or lead acid batteries.
The most telling thing I ever saw was an ad for LPG fueled forklifts about 15 years ago, that admitted (even then) that electric was "less overall cost of ownership between years 5 to 10, but hard to find anyone who would work on them, where LPG could be repaired by anyone who could work on gasoline motors"
Since most managers can not see past the end of this current month, the driving factor is more often the environment the machine will operate in, and not what the company plans on doing in 8 years from today, when the capitalization of the more expensive (electric powered) unit pays for itself.

How would you calculate the fuel savings for a standard LPG forklift? Assumptions are an 8 hour shift two 15 minute breaks and one thirty minute lunch break.

If anyone could help me out it would be greatly appreciated.

Thank you

George

A Class 1 forklift with a fuel cell power pack is running about 18-hours before the onboard H2 fuel tank needs to be replenished (3-5 minute operation). An AGV at one plant in Tennessee runs up to 27 hours. Average payback with multi-shift operations is about 2-4 years, excluding the new IRS $1,000 per kW tax incentives for 2006/2007. Fuel supply is not a barrier to entry. Hydrogen is a commonly available industrial gas extensively used in the food and petro-chemical industries and the US has excellent existing infrastructure for its timely delivery. www.generalhydrogen.com.

You also have to subtract the value of every cycle of battery life you lose. Cost of battery divided by 1500 life cycles to figure a true cost

with regards to Forkdave,where he calculates how much it costs for the fuel consumption of an electric unit,
I think it is not easy to calculate what
it is the actual costs of charging.

I have read a technical article a few months ago that shows a different value.
this study calculates the electricity
required to charge a forklift battery
taking actual plant measurements of electricity consumption and forklift hourmeter readings.

According to this study prepared by LD Bailey and Associates the actual energy consumed is 23.5 KW hours to charge the battery for one hour of forklift operating run time. This means that the fuel costs of electrics would be higher and would even make LP trucks more advantageuos.

It would be interesting to see other studys using actual charger consumption data to have a realistic cost comparision.

Another point to consider is that there is a large variety of models of electric trucks so you can match exactly the job to the truck.

-michael

Great responses. But to answer your question more specificly Jordan, an electric lift truck has as much lifting "power" as a gas unit. However, lifting and sideshifting and any other attachment is where the electric trucks use most of the battery "power". It is extremely difficult to say how long a charge will last. A given truck in application "A" with a poor operator may last only 3~4 hours. The same truck in application "B" with a good operator may last an eight hour shift.

Very good response Forkdave,
I would like to add the following:
A number of years ago I worked for a major forklift supplier and was supplied with the following information:
Electric VS LPG Forklift
Total operating costs over 15 year lifespan of each forklift type including purchase price, maintenance costs, repair costs, Fuel costs, electricity costs, battery replacement costs, and trade-in value at end of 15 years.

LPG Forklift: $2.38 per hour
Electric Forklift: $0.85 per hour

And this was before the introduction of AC Electric Drive systems which are reported to be 31% more efficient than DC Electric Drive systems.

I have driven the newest 5000lb pneumatic AC Electric forklift and was astonished at the power on acceleration and lifting speed, easily matching a 52 Hp pneumatic LPG forklift.

The downside of Electric forklifts is the initial purchase price is higher because of battery and charger costs are in addition to base forklift price.
The downside of pneumatic forklifts is the shorter overall lifespan, 15 years to the boneyard VS 25 years for the average electric.

I wrote an internal article for company news magazine a year ago on this subject. I am nIn the warehouse environment a battle is waged. With little empirical data to back up their arguments, managers continue to battle over which is best, the LP or Electric forklift.

This is the first in a series of articles that will examine the variables involved in total cost of ownership of Electric and LP forklifts (trucks) and discusses the differences and potential impact that these costs can have in the manufacturing and warehouse environment. These articles will cover how each truck operates and what costs are associated with this operation.

Historically, the LP truck has been the workhorse of the industry. If well maintained, LP trucks are efficient and relatively clean to operate. However, new developments in electric motor and motor control technology have enabled the Electric truck to replace the LP truck in some work areas. These articles will examine the cost impact for a business as it relates to the usage of Electric and LP trucks.

What are the costs differences between Electric and LP Forklifts? There are differences in the costs of the two types in purchase price, maintenance, refueling equipment, storage of fuel/ charging equipment, and refuel / recharge times. There are, for instance, the costs of an extra battery and battery charger for the Electric truck which do not exist in the LP truck. Electric trucks produce a cleaner, quieter and environmentally safer warehouse environment. However, LP trucks that are properly maintained have little environmental impact. LP trucks run longer with more lifting power and speed for more efficient warehouse operation. Here we will limit our discussion to the actual cost of fuel consumption of each type truck and not the corresponding external costs for refueling at the end of the shift.

In order for there to be a fair assessment in fuel consumption, there needs to be a median standard that allows both trucks to operate effectively. So for the purpose of this discussion we define the work cycle as an eight hour shift with two fifteen minute breaks and one half hour lunch for a total of seven hours of work time available. The work environment will be a standard controlled warehouse with no extremes in temperature or lift conditions and a smooth concrete floor surface.

Both vehicle types are designed to perform to this environment with only a single fuel load (LP tank or Battery Charge).

The standard 5,000 lift trucks in our example will use either an 8 gallon LP tank (LP) or a 480Ah, 80 volt battery (electric). The rule of thumb on electric trucks is that they use 20% of the battery's charge to operate. At the 80% of charge point, the truck begins to lose functionality (speed, lift, etc.) The efficiency of the charger and losses in the cabling, etc. is such that the battery will be charged to 105% of the rated capacity.




As a standard procedure, the LP unit must have the tank replaced or refilled after each shift and the electric unit must have the battery replaced with a charged one or recharge the battery on board for an extended period of time. These costs are not a part of this discussion but will be addressed in a future article.

To calculate the cost of fuel consumption of the electric unit, first multiply the batteries Ah rating (480Ah) times 20% to obtain the current usage. Multiply the current usage by the battery voltage (80V) to convert to Kilowatts per hour (kW). Multiply the kW by the number of hours worked (7) to get the number of kWh consumed; the kWh is multiplied by the efficiency recharge then multiply to arrive at the true kWh consumed. Multiply the kWh consumed number by the price of energy per kW to get actual power usage cost. (The advertised power rate in Atlanta is $.088 per kW.)



480Ah X.2 (consumed) = 96 W (consumed
96W X 80V = 7680 Watts or 7.68 kW
7.68 kW X 7 hours = 53.76kWh (kilowatt hours)
53.76 kWh X 1.25 (charge<

I'm sure many people are better qualified than me, but here goes:-
1)Trucks are rated by lifting capacity (among other things) so a 1 tonne truck will lift 1 tonne irrespective of it's power system. It may however vary in overall size.

2) Charge will vary according to battery size and type and hours of daily use. But probably 6 hours? The norm is to have spare batteries on charge to swap over in 24 hour operations.

3) Electric trucks do create waste but not in your workspace - they use electricity which is provided from clean, or dirty, power stations depending where you live.

Many people using this site are real experts and can advise you in detail. I have attempted to help but posting more particular questions either on this site or direct to a dealer rep would be more use to you.