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P3PPY
P3PPY Dork
6/22/21 6:40 a.m.

Yeah so what I'm getting at is how is an 18v mower even comparable to a 40? Brushless?

adam525i
adam525i Dork
6/22/21 8:39 a.m.

In reply to P3PPY :

If you take cordless chainsaws as an example Milwaukee's 16" version which runs at 18V comes with a 12Ah battery which works out to 216Wh of power in that pack. A comparable Ryobi 18" Chainsaw comes with a 40V (which is actually 36V nominal, marketing wank that Dewalt started with their 20V Max batteries) at 5Ah, that works out to 180Wh of power in the pack. So the Milwaukee actually has an extra 20% capacity in it but to deliver that same power to the tool will run at much higher amps which means more heat to deal with in the power electronics and motor. The battery packs themselves will just have the cells arranged in a different way, in the red tool you will have 2 parallel groups of 5 cells in series where the lime one will have all 10 cells in series (and those cells will be slightly lower capacity in this case). So at the battery cell level to deliver the same power in each tool is no different but everything else in the red tool will be built for high current/low voltage and the lime tool high voltage/low current.

Having said all of that, it is easier and more cost effective to insulate better than it is to handle a bunch of extra heat caused by higher current. The higher voltage stuff should deliver more power with less strain on the  system provided the components are all designed to handle the higher voltage, the extra heat from the higher current system is all lost energy. I can see why Milwaukee has stayed with 18V though as it keeps everything the same in their product line.

It's a shame that the Wh of the batteries aren't what is used in the marketing as it is an apples to apples comparison no matter what the voltage of the system and easier to understand for the average consumer (which is probably why they don't!). If you look on your battery packs though it will state the Wh capacity of the pack, this is important if you plan on flying with your tools, those packs should be in your carry on and under the max capacities laid out by the authorities. 

Edit: As found on the TSA website:

Carry On Bags: Yes (Special Instructions)
Checked Bags: No
Lithium batteries with more than 100 watt hours may be allowed in carry-on bags with airline approval. One spare battery, not exceeding 300 watt hours, or two spare batteries, not exceeding 160 watt hours each, are permitted in carry-on bags. For more information, see the FAA regulations on batteries.

That's a lot of battery per person!

GIRTHQUAKE
GIRTHQUAKE Dork
6/22/21 12:26 p.m.
P3PPY said:

Yeah so what's I'm getting at is how is an 18v mower even comparable to a 40? Brushless?

Gearing. Brushless DC motors have difficulty with starting torques and have to speed up to get past the strength of internal magnets, a problem called "cogging" in the E-bike world. It's why there's only one Electric car I know of that uses a brushless DC motor- the Smart EV- and why everything else except the EV drag racers use some flavor of Internal permanent magnet AC, because they allow control of that magnetic field and thus don't deal with cogging.

Adam525i 's post is also great, and his mention of "easier and more cost effective to insulate better than it is to handle a bunch of extra heat caused by higher current" Is on point. EGO for instance, is actually a 60V pack but it's nominal is 56V, and they try to make a lot of attention towards the bevy of controls and heat dispersal methods they use. I pay a lot of attention to these, and I literally haven't seen a single negative EGO statement other than their Chinese connections; even the Ebikers who use those packs in their bikes love 'em because they're so long lived and well built.

P3PPY
P3PPY Dork
6/22/21 7:00 p.m.

Oh well sheesh then like you said it's intentional confusion for the consumer and I have no idea if I'm buying garbage or not. Like my B&D string trimmer is 20v but would never ever be strong enough to power a mower, even for a short time.

Checking now, I see my trimmer is 30Wh. So okay is there a 1:1 comparison possibility for [battery Wh]:[power/strength of tool]? It seems like no, because other than common sense of chintzy tool=chintzy battery, B&D could have just attached a good battery to their garbage trimmer, right?

In other words, based on volts and battery capacity alone, I have no way of knowing if a 24v is going to be powerful or not, right? So I might as well go with a big voltage to get guaranteed power?

(Like if the rental counter had only two cars: a model that only came with a V6 or a model that came with either a 4 or a turbo 4. Getting 24v instead of 40v is taking my chances that I'll end up with a wheezing n/a 4 instead of a turbo?)

GIRTHQUAKE
GIRTHQUAKE Dork
6/22/21 8:52 p.m.

In reply to P3PPY :

Part of it is intentional, but the other part is how electric motors are driven. EBikes are a perfect example here- I have a "350 watt" controller that's really around ~620 watts at max because of how many amps x volts I plan on putting into it.

Since gearing increases torque- and torque is the real deal of electric motors- I would say focus on that coupled with reviews on battery pack lifespan and seeing teardowns before anything else. I would personally, go for something higher voltage unless you want to keep it in a part universe like Makita or something.

P3PPY
P3PPY Dork
6/22/21 9:08 p.m.

Thanks for the advice. I went with a 40v Greenworks 2.5Ah battery pole saw for $125 on sale. I have a bunch of work to do right away so I'll know within the return period if it's any good. I guess I coulda looked at tearsdowns first, but the proof will be in the pudding. 

adam525i
adam525i Dork
6/22/21 9:18 p.m.

In reply to P3PPY :

Watt Hours is a good way to compare how much battery you are getting regardless of the different voltages or amp hours with whatever tool you are looking at and it is easy to calculate (just watch out for the bs 20V/40V/80V, substitute 18V/36V/72V instead and multiply by the amp hours to get Wh, your 30 Wh 20V B&D battery is likely rated at 1.6 Ah (18V x 1.66Ah = 30Wh). The Wh is the capacity of the battery, think of it sort of like the size of the fuel tank but there is more to it. A battery cell can only deliver so much power at any time and live a long enough life, they're almost like a fuel tank and a fuel pump combined which is rated for a certain amount of power. The bigger the cells and the more of them the more power that battery can deliver to a tool.

At the end of the day though batteries are expensive and the more you are paying for a tool should have a direct affect on the capacity, quality and longevity of the batteries that you are getting. Because higher voltages deliver more power for less money (plastic insulation is a lot cheaper than more copper to handle higher currents in very, very simple terms) those tools will generally do better. The exception will be with higher end brands like Milwaukee that run at a low voltage of 18V but still delivers the power from the tool that is needed (at a price $$$). I would figure out what sort of yard tools you are interested in and then start reading/watching reviews of the different options available, eventually you'll decide on a brand and go with them as it is really handy to share batteries and have extras.

I personally just picked up a Ryobi 40V brushless trimmer along with their pole-saw universal attachment which has been great for me. It came with a 40V 4Ah battery that lets it run on high power for over a half hour (36V x 4Ah = 144Wh so you can compare with your B&D). In our current living situation that is all I need but down the road I hope to be in a house where I will also need a push mower and their options look pretty good. One of our neighbours has a Ryobi 40V snowthrower which really impressed me as well, a machine like that won't cut it right now in the winter for us but at different house could be an awesome option that would be a lot less intimidating for my better half then our current 1978 Ariens snowblower (which I am very fond of).

AAZCD (Forum Supporter)
AAZCD (Forum Supporter) Dork
6/26/21 12:28 p.m.

Just saw this in a HF email, not sure if I should ask here or in the pass/fail thread. Anyone know if it's good? I might get one this weekend.

Atlas 40V 15" trimmer $59.99

The Atlas 40V batteries look suspiciously similar to the Greenworks G-Max 40V, so I wonder if I could make them work.

P3PPY
P3PPY Dork
6/26/21 8:07 p.m.

In reply to AAZCD (Forum Supporter) :

I'm interested in knowing, too. I spent $68 on a bare tool greenworks 13" trimmer that uses the pole saw's battery. It seems made well enough and has adjustments for head angle and mid handle angle and location. It's not the 7 lb B&D, but I found I never used that one like a riding mower sidearm anyway. 
Greenworks 13” string trimmer

In other ways it's more chintzy like the edger wheel is a hollow plastic bit and when setting it down I accidentally bumped it from trimmer angle to edger angle

and for future reference the saw is this

40v greenworks pole saw 8”

raining all week so no chance to test yet

RacetruckRon
RacetruckRon Dork
6/26/21 11:57 p.m.
P3PPY said:

Yeah so what I'm getting at is how is an 18v mower even comparable to a 40? Brushless?

It's not. Most 18v mowers that are even remotely competitive with the +40v mowers are really two 18v batteries in series to make 36v.  The true 18v mowers are relatively small decks and have pretty poor runtime.
Ryobi 21" 40v and Ego are the only DC mowers worth buying.  Like any cordless tools, buy whatever battery platform you already have or what battery platform has the most tools you would like to own.  

AAZCD (Forum Supporter)
AAZCD (Forum Supporter) Dork
6/30/21 10:13 p.m.
P3PPY said:

In reply to AAZCD (Forum Supporter) :

I'm interested in knowing, too. I spent $68 on a bare tool greenworks 13" trimmer that uses the pole saw's battery. It seems made well enough and has adjustments for head angle and mid handle angle and location. It's not the 7 lb B&D, but I found I never used that one like a riding mower sidearm anyway. 
Greenworks 13” string trimmer

In other ways it's more chintzy like the edger wheel is a hollow plastic bit and when setting it down I accidentally bumped it from trimmer angle to edger angle

and for future reference the saw is this

40v greenworks pole saw 8”

raining all week so no chance to test yet

I have that Greenworks trimmer. It might be good for light trimming, but for me it was too weak for any significant weeds. I like the pole saw and it's probably the only one of my Greenworks 40V tools that won't go in the trash this summer. Both hedge trimmers (pole and regular) are dead.

I bought the Atlas 40V trimmer on Monday. It cut as well as the gas trimmers I've had and did 20 minutes of constant heavy use before the battery needed a charge. From pictures online it looked like it might take the Greenworks battery, but I decided that wasn't a good idea. It could probably work with a little Dremelling.

z31maniac
z31maniac MegaDork
7/1/21 11:46 a.m.

I need to sell our mower, trimmer, and edger attachment. My fiance accidentally left the garage open last summer and someone stole my tools, batteries and chargers for the lawn stuff. 

It all worked very well, but we started having someone do the lawn in the middle of 2019 anyway. 1800 sq ft house, on a 10,500 sq ft corner lot (one sidewalk to the driveway and one to the opposite street) = a ridiculous amount of trimming and concrete to edge. 

P3PPY
P3PPY Dork
7/1/21 10:05 p.m.

In reply to AAZCD (Forum Supporter) :

I just used the pole saw tonight. I'm very happy with it. My infant daughter was thrilled with it on the living room floor pre-use. Never have used one before so I don't have anything besides a regular chainsaw to compare it with, but it chewed through branches in a hurry! I'll point out that a tool that invites you to stretch farther than you're normally able + a ladder is something AD&D policies would do well asking about ownership of. When she wasn't reminding me that we have a much taller ladder in storage, and should t we just wait, my wife was so happy, running around the yard with the baby in one arm, pointing at offensive limbs "now this one! And this one!" :)

I don't like the trigger setup one bit. Were the thing to begin to tip out of balance, the part I'm trying to hold on to to control the descent is the part that's making the saw keep running.

Ill thoroughly test the string trimmer before the return window closes. I'm coming from a B&D 20v so hopefully it will be an improvement. 
 

z31 what kinda stuff are you selling off?

AAZCD (Forum Supporter)
AAZCD (Forum Supporter) Dork
7/1/21 10:22 p.m.

In reply to P3PPY :

Ah yes, I remember being up the ladder, leaning and arm fully extended with the chainsaw hoping that Mrs AAZCD wouldn't see me. Since I got my Greenworks Pole Saw, I don't even think about doing this.

z31maniac
z31maniac MegaDork
7/2/21 8:35 a.m.
P3PPY said:

z31 what kinda stuff are you selling off?

It's an 80V Kobalt mower, 80V Kobalt trimmer, and an edger attachment you can use on the trimmer power unit. IIRC, there is still one battery left. 

You can buy refurb'd batteries from Lowe's and the chargers for pretty cheap. But I'm in OKC, so probably wouldn't make any sense unless you are nearby.

Placemotorsports
Placemotorsports HalfDork
7/2/21 8:52 a.m.

I have on an old 36 volt Black and Decker weed eater that I've been using for years and still love it.  I was looking into getting one of the Dewalt 20v leaf blowers since I have a couple extra batteries for my drill that would work on it. Anyone have one of those?

P3PPY
P3PPY Dork
7/2/21 8:00 p.m.

In reply to z31maniac :

Family in SE Kansas so anything is possible. Kobalt and Greenworks are same form factor right? But it sounds like yours uses 1x80 instead of 2x40?

P3PPY
P3PPY Dork
7/5/21 7:30 p.m.

My experience with the trimmer was dramatically different than yours, AAZCD. I have no idea if the thing can trim its way out of a wet paper sack, because the auto feed isn't functioning. AND it wouldn't matter anyway, because the head kept knocking itself sideways into edger mode "STOP IT WITH THESE FENCES!! I WANT TO FIX YOUR AWFUL DRIVEWAY!!"

My wife gave up and got the "20"v B&D out of the basement and heaved a sigh of relief. Totally lacking in power, too short, doesn't have handle and head angle  adjustments-- but actually works. Also it's 6# instead of 9. 
 

UPDATE: I got the feed to work and it has all the power I need but despite the 20 points of angles to change it was never comfortable to use. That's an understatement. I'm trusting that your positive experience with their pole saw indicates that you've tried others you didn't like, otherwise I would assume they'd butchered the pole saw too and that there are much better ones out there. 

P3PPY
P3PPY Dork
7/21/21 10:06 p.m.

Greenworks pole saw works for cutting down 12" diameter trees. I would take a good horizontal swipe then tilt it up and "gas" it in case oil feed needs to be like that angle. 
However, I got to telling someone about the weed whacker and I decided to return the saw, too. I bought it to get into an ecosystem, not to have yet another battery and charger. I'm going to try out Ryobi 18v pole saw (surely it's too wimpy, right) and also see if the GW battery can fit into a Kobalt string trimmer -- if the Kobalt isn't also garbage, that is. 

tuna55
tuna55 MegaDork
7/22/21 3:14 p.m.

Update here.

 

I bought the older Ego brand string trimmer and have loved it for the past three years. I bought the leaf blower recently with no battery just a few months ago. I could often trim my yard and then blow off the driveway, patio (big!) and sidewalk on one charge.

 

Then the battery died.

 

Warranty service was no help because it was way out of warranty. It would not charge. I decided to take the plunge, and took it apart. In testing I found one cell to be flat, while the others seemed fine. I bought two cells for $20 shipped and soldered it in. Then I went back and unsoldered it and soldered it in the right orientation. 

 

Total success. The thing works like new, maybe better than it has been in a while. A new battery cost as much as a tool with a battery, so I was annoyed.

P3PPY
P3PPY Dork
7/25/21 6:41 p.m.

My genius plan is a bust. As expected, the 18v Ryobi just didn't have an oomph to it. Then the Greenworks battery doesn't even come close to fitting in the Kobalt's enclosed port. I didn't find anything else that I considered a good enough price. Another battery system it is :/

porschenut
porschenut Reader
8/4/21 8:29 a.m.

Update on the EGO self propelled mower.  After 4 seasons the drivetrain is extremely loud.  Not gas engine loud, but gone from a barbie jeep whine to a DTM straight cut gear scream.  Pulled the "differential" and it was completely devoid of fluid.  Not a serviceable item, but I filled it with  some 30 wt, no change.  Also cleaned and lubed the gears in the wheel hubs.  I think the damage has been done, no change again.  Yesterday the speed control rheostat died, leaving me with only crawl speed.  The harness that connects the rheostat to the base broke somewhere, easier to run 3 wires externally to get it working.  This cable flexes every time I fold up the mower for storage, so I guess 4 years is the engineered lifespan.  

I need 4 more seasons, at 70 plan to ask for a robot mower so hopefully I can keep it alive.  As someone who kept 2 stroke lawn boy mowers running for 20 years and snapper riders for even longer this is disappointing but not surprising.

Aaron_King
Aaron_King PowerDork
10/27/21 9:13 a.m.

In reply to porschenut :

Interesting on the dry diff.  I used some of our stimulus money to get an EGO, I guess I need to pull it apart and check once this mowing season is over.

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