ElectricMotorcycleForum.com
General Category => General Discussion => Topic started by: Apriliarsv on January 31, 2019, 05:00:22 AM
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http://www.thedrive.com/tech/26234/this-electric-caterpillar-excavator-is-the-tesla-of-heavy-construction-equipment
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It's impressive to see what can be with the existing battery technologies.
Can't wait for the next gen (Solid State).
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I am trying to figure out how much diesel is comparable to the energy in the 3 1/2 ton battery pack. 162 or 164 hp, kind of hard to run an excavator at full power with swing and dump so my estimate is 6 gallons per hour, seven hours, 42 gallons, times 7 lbs per gallon 294 pounds. Think I am close? The article does not state if a rough terrain forklift can take the battery to the charging place or if the machine must track there.
When we see machinery that is heavy on purpose go battery then it might be come of age. Maybe people really buy Telsa but seems leasing is the most common around here for auto.
Some of the other links on that page at present seem good like the school bus that could re charge mid day.
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The generally accepted equivalent of stored electrical energy to gasoline is 33.7kWh per gallon:
https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent (https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent)
For that cited 300-kWh pack, that'd be 8.9 gallons of diesel.
Of course, the powertrain should be running at say 90% efficiency with no aerodynamic concerns. So hopefully it can work for a full work shift before it requires a recharge.
Remember, of course, that a diesel engine has the least efficiency while idle, and the electric powertrain has the highest. So, maybe the start-stop workload is optimal for electric powertrains.
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My estimate was from an 81 horsepower John deere 5410 Nebraska test that gets 65 hp to the power take off shaft at something like 4.2 gallons per hour. The 6 gallons per hour estimate I put in is probably too high maybe by a factor of 3, depending on the use. I remember from school the efficiency of a carnot engine could be computed by the compression ratio. I have to question how close in gasoline equivelant at a power take off shaft those values found following the wiki link. Diesel is much better than gasoline at idle likely because there is no closed off butterfly valve (or similar) like gasoline.
The piston engines are not all that efficient, I hope 3 1/2 tons of lithium ion batteries could do better than two hours of mowing at near max power on my tractor.
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I wonder about recharging the excavator each night. ??? Would you pay to bring the charging infrastructure to the work site, or would you have a diesel semi-truck pick up the excavator every night and take it to a charging station, recharge it overnight and truck it back to the job site?
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Fully Charged talked with some companies about best uses for heavy equipment. The conclusion was basically that is where the hydrogen cells work best. It's such a tax on battery resources and equipment like this is often on a new location with no charging infrastructure.
It shows what electric power can do but still not the best use for now.
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I would expect the excavator to come with a one ton charger. The temporary power for the site needs to be sufficient. These articles are hardly any more than click bait.