Problem is current batteries don’t have a high enough energy density. The electric drive is not much of a problem. Looking at the dyno tests today, a 70cc saw makes around 6.5 hp. That’s 4.9kw. Let’s say it has to run at full throttle for an hour. That 4.9kwh. Right now lithium batteries are about 245wh/kg. So you would need a battery that has 5.4 kwh assuming 90% motor effiency, which would weigh 48.5 lbs. or 5 batteries that weigh about 10lb each to get 1 hour of cutting time or you could cut for about 12 min per battery.
let’s look at how much gas that would take. Assuming 20% efficiency, on the low side due to being a 2-st, we need 24.5 kwh of energy. With a gallon of gas containing 33.7kwh, we would need about .75 gallons of gas. That is only about 4 lbs.
Don’t take this as I don’t like electric power, I am just skeptical of its usage in many applications without a major breakthrough in battery technology.
Good to see some figures, and am not questioning them, I have not done any
maths myself, am leaving that to the people who get paid to do it and come up
with the goodies. But a lot of work is done with much less powerfull saws,
the race to the end will have to stop, new ways of going about such tasks as
cutting trees will have to be intorduced, and the resulting economic factors
catered for.
48 lbs seems alot of weight, but then look how big the first computers were.
Look how carbon fibre lightened up things too.
Look how motors have become digital,
things are a changing.
Dolmar had a nice fourstroke engine, they dropped it, someone who used it praised
how well it ran, how much torque it had too, maybe for the bigger trees that batteries
would be a problem with this or even more up to date engine tech would be an option.
On a less positive note, if the planet keeps on burning and the insects keep
getting nastier, we may have a lot less trees to cut, they sure can be destroyed
in a short space of time, much faster than we can grow replacements.
