Cost to run: electric vs gas

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  • Updated 3 years ago
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Here's my newest video on the EGO mower, my findings on the cost to run. I hope you enjoy!
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Luke

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Posted 3 years ago

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Blue Angel, Champion

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Great video!!!

It's been so long since I used a gas mower I have no idea how much fuel it burns... maybe someone can chime in? It would be neat to see by how much $/year the Ego beats a gas mower.
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Steve Valdes

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It's great to know it's only about $.02 a full charge for the 4Ah (or 5Ah?). Should we include the cost of the battery over it's life span; say 500 charges(or?) also as a cost to replace fuel? I'm on the fence regarding this at this point.
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Jacob

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Um. No.
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Blue Angel, Champion

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Jacob, great work with the numbers!

I do have to add something though. WRT the efficiency of a gas mower engine, 40% is pretty optimistic! The 2016 Prius made headlines last year when Toyota's Engineers managed to crack the 40% thermal efficiency barrier:

http://www.hybridcars.com/2016-toyota...

The average modern car engine, with all of its advanced combustion chamber design, direct fuel injection and all the other tricks mixed in, is only about 30% efficient. I would be amazed if a gas lawn mower was even 20% efficient.

The other thing to keep in mind about gas engine efficiency ratings, they are all stated for the engine's peak operating efficiency, as in the best spot on the BSFC (Brake Specific Fuel Consumption) curve. When an engine is operating at anything but its optimum combination of speed and load, it's efficiency drops from that peak value... one of the reasons we see more and more speeds in car transmissions (keeps the engine in its sweet spot over a broader range of operating conditions).

In practice I would bet the average gas mower is extremely inefficient. Having said ALL that, we could just use someone's real usage data instead of going grey trying to calculate it. :-)
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David Cline

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Well not factoring some battery cost into the comparison is essentially the same as saying batteries are free and last forever. But that could actually be better than guessing what batteries will cost 5-10 years from now and ending up way off.

It's not at all uncommon to ignore some costs in this sort of analysis (salespeople do it all the time), usually for sake of simplicity or irrelevance to the immediate decision being made.

I'll never forget a physics professor I had who lamented having to control for or exclude variables that could never actually be ignored in the real world. He would grumble, "this is like studying massless elephants on frictionless planes."
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ClarkM

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I hope you know that was a joke...
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Jacob

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Ugh good. People on here sometimes are just looking for a reason to cause an argument.