Variable Mower RPM

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If the blowers, string trimmers, and snow blower have variable speed controls, will ego make variable speed control for the blades of the 21" mowers? I think that would solve a lot of issues, if the blade is working fine at low speeds, then you could leave it there, but if putting it on "turbo" gives you better results at the cost of battery life, at least you'd have the option. Just saying.
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Deleted

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Posted 3 years ago

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keenanj

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I agree. I have argued for this before. Just like the Tesla has insane mode, or whatever that is, the tools should have a mode where power is emphasized over energy saving. I have a ton of batteries and a ton of chargers. To me, I'd often go for more power. However, when I first joined the Ego line, I appreciated the more 'economical' strain on the battery.
Today I spend the entire day mulching leaves, using the mower and the blower. It would be nice to have the option to have the mower with more torque and / or more speed (on the blade motor). That being said, what they have designed works pretty well, at least for my needs.
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Dominic49

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issue beeing with an 'insane' mode is that heat will build up pretty quick. There isn't a ton of thermal mass in the motor and definitely not a ton of clean airflow going over it.
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keenanj

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Dominic49-My question, which I don't have a clue, would be for the mower (as it is currently designed) to be at full power would that be a heating issue? Yesterday I had the mower kicking in when a went over a pile leaves. If it stayed in that mode would heating actually be an issue? If for a full hour a pushed the current mower to the limit, would that kill it? If our mowers could handle it, it's probably a software mod to change it to what Spark and others have previously suggested. 
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Deleted

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When you say "ton" how much do you mean? I have in total 100 amp hours worth of ego batteries (ramen noodles for dinner every night) and exactly I would happily give up 20% of that to be able to go full power with the mower if it mean leaving a much cleaner cut. Hopefully the high lift blade will compensate....we'll see. 
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Blue Angel, Champion

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Spark, this is a good idea in my opinion, and one that's been discussed several times already. There are competitors products that offer something similar in that they have more than one operating mode, tailoring the mower for either efficiency or powerful cutting.

Gas mowers usually have a throttle to control engine speed, electric mowers could benefit as well. The tricky thing would be to market it successfully, since everyone seems to concern themselves only with how much run time a battery tool is good for. It might be tough to explain to non-technical types in a way that won't sound like the efficient modes/speeds have inferior cutting performance?
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TheAtomTwister

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Blue, I'm not sure I agree with the part about difficult marketing. A mower with the cutting power and mulching power of gas would draw much attention. The professionals would like to have adjustable power right on the handle. Have it be a dial much like that on the blower.

Yes, as far as how things can go wrong during warranty period goes, I'd just make a more expensive , more rugged, more powerful model built for much heavier use.  That isn't something suited for the homeowner, but it is for the pro. I am unaware of any plans that you have for creating products oriented for the professional, but if you do make such plans, I would be a buyer for sure.
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matt.mackinnon

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I am sure that a more sturdy and 'pro' developed model could be made.  where the problem comes in is would you sell enough to justify the cost to build.  
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Deleted

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Give it another two years for some more lithium battery advancements, gas powered machines will be a thing of the past....I just hope Ego keeps developing to stay ahead of the curve.  
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Blue Angel, Champion

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TAT, by difficult marketing I mean, it would mean explaining why you need to choose between run time and performance.  In an ideal world you just have a product that works, and the user doesn't need to understand anything... turn the key and it goes.

That's the marketing team's dream anyway.  People who understand how things work know better. :-)
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TheAtomTwister

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True, but I was thinking about how some people complain about not having enough power or having electric mowers that stall easily. A lot of people who have owned electric mowers have had that problem, that is why I'm saying that the marketing might not be so difficult. You are however correct, I imagine, with people who have not owned underpowered electric mowers. 

Matt, you are right as far as many professionals in the United States goes. Husqvarna has more advanced and powerful battery powered equipment for sale in the UK, so does Bosch with their 36V heatsinking, weatherproof batteries, to my knowledge, that stuff is only available in the UK. In time, the market for such tools will expand as the technology progresses as Spark Lawns is suggesting it would.
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While i understand the need for economy and heat dissipation.... If the back back blower i use can run on turbo all day and handle it I'm sure the mower can. Worse case scenario i don't see how a micro turbine can't be added in the motor housing to increase air flow around the housing. There's a way to do everything...but if roi isn't profitable it won't be done, especially if the already expensive mower gets more expensive. Then again whose to say i wouldn't pay the same for a walk behind mower with throttle control as i do for the self propelled model....
(Edited)
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Blue Angel, Champion

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I somehow doubt heat is the issue, as Dominic49 suggests. Extending battery life is very likely the only reason for the load-based variable speed.

The 20" mower is a constant speed unit and has no overheating issues.
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Dominic49

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IIRC the 20" mower is constant speed without ramping. However, it is programmed at a level that would not cause it to overheat under normal circumstances.
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Blue Angel, Champion

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I get the impression the 21" mowers are significantly more powerful than the 20", and I have yet to hear of someone having overload issues with one. I've seen a few videos where people have chewed through some pretty crazy stuff and the 21" just keeps on chugging.

One of these videos was just put out yesterday by Oz Tool Talk. Check out what he puts the mower through... only when the battery is almost dead is he able to get it to shut down, and that's with the SP on full speed cutting tall field grass in mulching mode!

https://youtu.be/KBzGmVZ-ns8

This certainly doesn't seem like a mower with thermal issues.
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(a)Typical Engineer

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The 20" mower has a mode where by when it detects additional load, it spins up faster (within a second), then ramps back down slower (within 3-5 seconds).

The only technical hurdle with a variable speed on the mower, as well as with running it at high speed for a continuous amount of time is that the motor is BRUSHED versus all the other tools which are BRUSHLESS.  You'll notice that the motor has no heat sink fins in the last picture below; which likely would not help (except for passive cooling) since there isn't any air flow; which is another significant difference to the hand held tools which have their motors open to ambient air.




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Blue Angel, Champion

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Later 20" mowers and all 21" mowers have a fan integrated into the blade mount. I believe the main purpose of this fan was to cover the exposed motor windings since people were concerned about dust and debris or moisture entering into the motor from beneath:



There is, however, airflow through the motor exhausting out through the bottom holes, even on the 20" mowers without the fan. With the blade spinning, air is moving in a circular motion under the mower deck. This circular motion creates a low pressure area in the middle where the mower vents are, drawing air out through the motor.

It's the same phenomenon that creates the storm surge at the eye of a hurricane. All of that air mass rotating around the eye drops the atmospheric pressure and the local water level rises.

After two and a half seasons of mowing, the lower armature windings of my 20" mower, visible through the lower vents, are still clean with no sign of dirt or grass clipping debris. :-)

I have mechanically overloaded my 20" mower walking fast when the grass was too thick, but I've never managed a thermal overload on the mower or battery.

Actually, that brings up a good question: Since you've had your mower apart, do you see any temperature sensors on the motor itself?
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Dominic49

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no temp sensor on the 20 inch mower motor. (or the motor on the 480cfm blower for that matter)

If I can ever get all the dang RTV off the motor controller I'll have a better Idea of what is going on behind the scenes. (I haven't been putting in a ton of effort on it though just fiddle with it every now and then.)
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Blue Angel, Champion

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If it's anything like the potting on the BMS board in the batteries, good luck! :-)





It may not look it, but that was a lot of work! ;-)
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(a)Typical Engineer

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No external temp sensor on the motor, but the control module (black box hanging from the wire harness) does sit right on top of the motor, so it is close enough in proximity to the motor case that it could detect an over heating condition. Or the control module could detect increase current flow, and shut down based on probably over heating being forth coming.
(Edited)
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John

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Has anyone had any success forcing it to high power mode manually?  I would love to have this ability to be able to get through my neglected yard.

On a side note, does anyone know if the 2 battery mower is actually a higher power motor or just longer runtime?

I don't want to go back to gas, but thick Bermuda is trouble for these things.