Project Farm electric saw shoot-out

[el33t]

I have often thought that electric tool technology would jump light years ahead if it could ever be figured out how to make a battery that stores AC current. Or, create a fuel cell that could accomplish the same thing in a power tool size format.

AC produced directly in electrochemical cells? I don't think so. AC is generated when a conductor moves in a magnetic field.
Besides, it wouldn't make much sense.
We produce alternating waveforms at the frequency we need using solid-state switches with efficiencies exceeding 90%.
In general, AC with a (grid) frequency of 50/60 Hz is very inefficient for power conversion purposes. Therefore, inverters operate at frequencies ranging from tens of kilohertz all the way down to a few megahertz.

AC from the power grid is increasingly used via VFDs rather than directly, especially for induction motors. VFDs convert AC to DC and then to variable-frequency AC, saving energy by optimizing motor speed for partial loads.
Many household appliances, like fridges, now use inverter-driven induction or permanent magnet motors to improve energy efficiency by adjusting compressor speed.
In general, DC is much more useful in the modern world.

I don't see much chance of using fuel cells in the near future in handheld power tools, if only because of their limited current capacity. There would have to be some kind of breakthrough here, and that's not likely to happen, since they were invented back in the 19th century with the first commercial applications even before WW II.

 

[HumBurner]

Meanwhile, we already have chainsaws that are supposed to correspond to "80cc". I would call that progress.

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OPTIMUS™ Chainsaw 4.5 kW

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Ignorance and stubbornness shine through when you start talking battery saws/tools. Some folks'll never get there just because.

That being said, battery saws aren't right for every single cirumcumstance one may find themselves in.

 

[FergusonTO35]

Meanwhile, we already have chainsaws that are supposed to correspond to "80cc". I would call that progress.

OPTIMUS 82V 5.0kw 28" HOG Chainsaw Kit with CORE530 Battery & DP Charg

Equivalent power to 80CC gas powered chainsaw Mechanical & Electronic Inertia-Actuated Chain-Brake: For Added Safety & Security HMI Technology Display For Premium Read-Outs & Visibility Metal Bucking Spikes For Enhanced Gripping & Performance Molded-In Felling Sights: For Reliable Felling...

www.greenworkscommercial.com

OPTIMUS™ Chainsaw 4.5 kW

The CS45 is the most powerful battery chainsaw we have ever made for professional use, offering industry leading power and torque to make the most demanding jobs easy. Premium components include magnesium housing for additional durability and optimised cooling, while the 4.5 kW motor delivers...

cramertools.com

I like how Greenworks seems to take the actual construction of their tools seriously and not make everything out of thin clamshell plastic like other battery tool makers. I still can't get over how awful the Stihl battery stuff looks every time I walk by it. Even their absolute bottom shelf gas machines like the FS-38 are way more respectable.

 

[RCBS]

'Already'? LOL

First battery powered chainsaw was in the 90s.

 

[Philbert]

First battery powered chainsaw was in the 90s.

Yeah. But 36V, Li-ion batteries created a new class of battery powered OPE (*eventhough there are many, different, voltage platforms today).

First introduced in Europe, they started showing up in US about 14 years ago.

Ironically, the 12V Makita saw from the 1990’s presaged the STIHL GTA style mini-chainsaws that became popular recently.

Philbert

 

[sawfun]

Meanwhile, we already have chainsaws that are supposed to correspond to "80cc". I would call that progress.

OPTIMUS 82V 5.0kw 28" HOG Chainsaw Kit with CORE530 Battery & DP Charg

Equivalent power to 80CC gas powered chainsaw Mechanical & Electronic Inertia-Actuated Chain-Brake: For Added Safety & Security HMI Technology Display For Premium Read-Outs & Visibility Metal Bucking Spikes For Enhanced Gripping & Performance Molded-In Felling Sights: For Reliable Felling...

www.greenworkscommercial.com

OPTIMUS™ Chainsaw 4.5 kW

The CS45 is the most powerful battery chainsaw we have ever made for professional use, offering industry leading power and torque to make the most demanding jobs easy. Premium components include magnesium housing for additional durability and optimised cooling, while the 4.5 kW motor delivers...

cramertools.com

Those are like $1200.

 

[Ketchup]

Those are like $1200.

12 bills isn’t crazy considering what modern saws retail for. The hitch is that if you want a second battery (and you do) the cost is closer to $1700.

 

[Ketchup]

This one just showed up in my mailbox too!

View attachment 460030

Philbert

A cordless 16” circle saw would be a lot easier to use than the corded version.

 

[el33t]

I like how Greenworks seems to take the actual construction of their tools seriously and not make everything out of thin clamshell plastic like other battery tool makers. I still can't get over how awful the Stihl battery stuff looks every time I walk by it. Even their absolute bottom shelf gas machines like the FS-38 are way more respectable.

Maybe Stihl (family) knew what they were doing when they acquired a minority stake in the Greenworks (or Cramer) equipment company in 2016.

They now own 18.52%.

12 bills isn’t crazy considering what modern saws retail for. The hitch is that if you want a second battery (and you do) the cost is closer to $1700.

I also thought it was not so expensive, considering the newness of the product. MSRP of the 500i is $1600. Of course, the price of the additional battery is rather shocking.
In addition, Greenworks is one of those companies that does not allow the use of any batteries. The battery and the powered device talk to each other using their proprietary protocol. When the controller thinks it's dealing with a non-original battery, it won't allow the device to start.


The 500i has a tank capacity of 0.76 l. Assuming a gasoline density of 750 g/l, there is 570 g of fuel in a full tank. Let the BSFC for the 500i be 500 g/kWh (measured value for max. torque). That is, 1 tank of 500i should produce 570/500=1.14 kWh on the shaft.
Greenworks battery capacity is 530 Wh. That is, theoretically, one tank of 500i is more than 2 full charges of Greenworks battery - even without taking into account the never 100% efficiency of an electric saw.
However, given what I described in my post in this thread, I would not be surprised if in reality the number of cuts
of the same "amount of wood" in both cases was similar.

 

[Ketchup]

Maybe Stihl (family) knew what they were doing when they acquired a minority stake in the Greenworks (or Cramer) equipment company in 2016.

They now own 18.52%.



I also thought it was not so expensive, considering the newness of the product. MSRP of the 500i is $1600. Of course, the price of the additional battery is rather shocking.
In addition, Greenworks is one of those companies that does not allow the use of any batteries. The battery and the powered device talk to each other using their proprietary protocol. When the controller thinks it's dealing with a non-original battery, it won't allow the device to start.


The 500i has a tank capacity of 0.76 l. Assuming a gasoline density of 750 g/l, there is 570 g of fuel in a full tank. Let the BSFC for the 500i be 500 g/kWh (measured value for max. torque). That is, 1 tank of 500i should produce 570/500=1.14 kWh on the shaft.
Greenworks battery capacity is 530 Wh. That is, theoretically, one tank of 500i is more than 2 full charges of Greenworks battery - even without taking into account the never 100% efficiency of an electric saw.
However, given what I described in my post in this thread, I would not be surprised if in reality the number of cuts
of the same "amount of wood" in both cases was similar.

It definitely seems like the Hog goes through batteries quickly. The 500i doesn’t sip. Having to run for a battery twice as often as filling the 500 would be pretty annoying. For any large cutting you would probably need 3 or 4 batteries just to keep working.

 

[Powerstroke Cowboy]

It definitely seems like the Hog goes through batteries quickly. The 500i doesn’t sip. Having to run for a battery twice as often as filling the 500 would be pretty annoying. For any large cutting you would probably need 3 or 4 batteries just to keep working.

When you watch the video, the guy that owns both said the same thing.

That's the first electric saws that's actually truly impressed me. Till I realized how much upfront cost it would be to even be useful if you were planning to cut all day.

 

[HumBurner]

When you watch the video, the guy that owns both said the same thing.

That's the first electric saws that's actually truly impressed me. Till I realized how much upfront cost it would be to even be useful if you were planning to cut all day.

I'd be far more interested in the HOG over the Milwaukee dual fuel 70cc saw, largely because of the 3/8" chain and contained battery. Not quite at a point where I can drop that kind of $$$ though.

I'd love to test it out in some knotty white oak or wood prone to barber chairing to see how it really pulls.

 

[Ketchup]

When you watch the video, the guy that owns both said the same thing.

That's the first electric saws that's actually truly impressed me. Till I realized how much upfront cost it would be to even be useful if you were planning to cut all day.

My experience with battery saws is they do a lot better in small cuts than large. My trim
saw can do hundreds of 3” cuts on a single 2.5amp battery, but only 3 or 4 of 10” cuts. I expect the Hog is similar. 20-24” cuts probably don’t drain the battery anywhere near what a 36” does. It is also notable that he’s running skip.

It’s relatively rare that I need a 36” all day. Mostly I need 2-3 large felling cuts and 20-30 bucking cuts. And that’s a big day, maybe 1 in 10 work days come close to that. Still, those kinds of cuts are usually at the end of the day and we don’t have space to wait for batteries to charge. Probably not the best application for the Hog. Might be nice for cuts in the tree though. No pull start…

 

[HumBurner]

I also can't find any real specs, specifically chain speed, on the 5.0kw HOG. If it was even close to 9-10k under load, that'd be a huge selling point. The dual fuel is max 7200rpm, which is likely under no load as max stats often are.

 

[Philbert]

I also can't find any real specs, specifically chain speed, on the 5.0kw HOG.

I’m missing the HOG reference. Was it one of the saws he reviewed?

Can you post a link to their website or seller?

Thsnks.

Philbert

 

[el33t]

I’m missing the HOG reference. Was it one of the saws he reviewed?

Can you post a link to their website or seller?

Thsnks.

Philbert

Yes, the newest saw is OCS 800 aka H.O.G. (High Output Gasless).

I posted the links in one of the previous posts in this thread. And their reported chain speed is 98 feet per second.

OPTIMUS 82V 5.0kw 20" HOG Chainsaw Kit with CORE530 Battery & DP Charg

Equivalent power to 80CC gas powered chainsaw Mechanical & Electronic Inertia-Actuated Chain-Brake: For Added Safety & Security HMI Technology Display For Premium Read-Outs & Visibility Metal Bucking Spikes For Enhanced Gripping & Performance Molded-In Felling Sights: For Reliable Felling...

www.greenworkscommercial.com

I guess this video can be useful:

Post in thread 'Project Farm electric saw shoot-out'

May 22, 2025

I want to like the 'lectric saws, but remain unimpressed. They've been out over a decade and are just now cracking 60cc power levels? Sigh. It can only mean that the batteries are the choke point.

There are battery powered cut-off saws that exceed that 60cc power level, but they are heavy.

Meanwhile, we already have chainsaws that are supposed to correspond to "80cc". I would call that progress.

OPTIMUS 82V 5.0kw 28" HOG Chainsaw Kit with CORE530 Battery & DP Charg

Equivalent power to 80CC gas powered chainsaw Mechanical & Electronic Inertia-Actuated Chain-Brake: For Added Safety & Security HMI Technology Display For Premium Read-Outs & Visibility Metal Bucking Spikes For Enhanced Gripping & Performance Molded-In Felling Sights: For Reliable Felling...

www.greenworkscommercial.com

...

• el33t

• 

 

[el33t]

My experience with battery saws is they do a lot better in small cuts than large. My trim
saw can do hundreds of 3” cuts on a single 2.5amp battery, but only 3 or 4 of 10” cuts.

The likely reason for this is that the capacity of Li-Ion cells, like other electrochemical cells, depends on the discharge current. The standard discharge rate for which manufacturers quote the capacity of the cell is 0.2C, or 5 hours. For higher discharge rate, the capacity will be lower, due to the (thermal) losses on the internal resistance, which increase roughly in proportion to the square of the current.

An example of the discharge rate characteristics of a high-current 21700 cell:

 

[Philbert]

Yes, the newest saw is OCS 800 aka H.O.G. (High Output Gasless).

I posted the links in one of the previous

Thanks.

I have said something similar many threads, but a battery-powered saw (or any tool) does not gave to equal the power of a gas, or corded, version of that tool to be useful.

It just needs to perform effectively for the task(s) that it is used for.

Most folks on these forums own / use more than one chainsaw (limbing, bucking, felling, pole, etc.). A battery-powered chainsaw does not need to pull a 36” bar to be a useful, and appropriate, saw for many tasks.

Philbert

 

[Powerstroke Cowboy]

My experience with battery saws is they do a lot better in small cuts than large. My trim
saw can do hundreds of 3” cuts on a single 2.5amp battery, but only 3 or 4 of 10” cuts. I expect the Hog is similar. 20-24” cuts probably don’t drain the battery anywhere near what a 36” does. It is also notable that he’s running skip.

It’s relatively rare that I need a 36” all day. Mostly I need 2-3 large felling cuts and 20-30 bucking cuts. And that’s a big day, maybe 1 in 10 work days come close to that. Still, those kinds of cuts are usually at the end of the day and we don’t have space to wait for batteries to charge. Probably not the best application for the Hog. Might be nice for cuts in the tree though. No pull start…

I personally believe they would be a great in tree saw. For that exact reason. Small branches and no pull start. I'd like to think they would be a climbers friend.

The big hold up is the batteries. If they can get that figured out, then they will have something.

 

[Ketchup]

I personally believe they would be a great in tree saw. For that exact reason. Small branches and no pull start. I'd like to think they would be a climbers friend.

The big hold up is the batteries. If they can get that figured out, then they will have something.

The Echo dcs2500 is my daily driver. My company just bought 3 more. We remove a lot of trees with the t542xpi as well. And the battery Husky extendable power pole is pure gold.
The HOG probably wouldn’t see as much use as those, but if you have ever spent a few hours in spurs running a 390xp, a no-pull option seems worth considering. Weight is still a downside as much as number of cuts. They have farther to go, but at least the technology is moving forward. Right now, those 94cc 372s @upstateamish is building are a more exciting option.