Neuton 5.1 Electric Mower... Possible Upgrades

[etard]

I happened across this mower after I saw the Ryobi cordless mower was on sale at Home Depot this weekend. Well, a quick search on Craigslist revealed other older cordless mowers for cheap, so for $17 I could not go wrong.

This particular mower seems to be complete and battery charges up and the blade seems to turn as it should. Voltage after charge is 27.4 volts with an SLA 24 volt 10 AH battery. I have not cut the grass, but tomorrow I will. However, I could not resist opening her up and seeing the workings of the little green neut.

This task could not be easier, four philips screws, no tabs or clips or anything! This revealed a brushed motor directly driving the blade. Hmmm, I wonder if I can fit this hubmotor in there? I'll have to pop the cover off right after I mow the lawn tomorrow and check the motor temp with my calibrated hand to see if I think some more volts can't be added to the mix somehow. Hmmm, I wonder how hard it would be to make it RC?

I really like the overall design of the mower. The key is a neat feature and incorporates a pop out fuse in case the motor gets bogged to much. It is really light compared to a gas mower, so it wouldn't take too much power to move it around remotely. One lever adjusts all the wheels, even the handles trigger feels good and solid. The handle uprights do feel flimsy as they connect to the mower body, but hey the thing's all plastic!

If anybody is interested in these things, I will post some pics later, I am open to suggestions for improving the power and features that would improve my experience with this mower.

 

[dnmun]

sharpen the blade as much as possible and go slow since the SLA will be sagged out. i had a B&D someone gave me free, and i fixed it and used it a little but it was 24V 18Ah and still it would sag. but it would cut light grass.

maybe try more volts and better battery next? but sharpen the blade since that is where the sag will come from.

 

[etard]

That is first on the list, it definitely needs some sharpening. I forgot to measure the motor to see possible size comparisons to other motors and get a better idea of what the power output is.

I am wondering how hard it would be to gut a rumba vacuum and use the computer guidance on that retrofitted onto this motor.

 

[dogman dan]

You would be the one to make a frankenhooker mower. 8) I wouldn't recommend going too overboard volting up. I think it's very similar to the 24v B&D. Mine is the B&D, and overvolting it makes it run too hot, even if the load is minimal.

They run great on HK lico. I wouldn't want to use a bms pack on it, my mower can easily spike 60 amps or more.

6s works fine on light to normal cutting, 7s works great for thicker grass like I get after actual rain happens. By 10s it's just overheating and popping the temp protection breaker too fast to be useful. I never tried 8s, that might run long enough to work well on thick stuff. I have found 7s to be quite adequate for even the thickest cutting I get. No weeds 3 feet tall, just thick grass left unmowed till it's 6-8 inches tall.

So light with the lico aboard, I feel like I'm just pushing an empty baby buggy around the yard.

Sharp blade for sure, but on 7s mine still cuts great when it's been awhile.

 

[lbz5mc12]

I want an electric lawn mower so bad. My gas one likes to scare the crap out of me sometimes. It likes to back fire occasionally when I'm starting it up. Of course Mom's not gonna let me take it apart and use the chassis to make an EV mower. I don't even think it would be that hard. A couple of gears, a Currie motor/controller, a thumb throttle, an on/off switch, some SLA and a way to mount it all.

 

[dnmun]

just watch the CL free page and go get one when someone gives it away. usually they just lose the key or the charger and then when it doesn't work they throw it away. not everyone gives stuff away on CL but the 1% that does is enuff for you to get one if you watch.

 

[Tommy]

I found two used ones on craigslist($30, $100) then paid $289 for a new one so I could get a 54" cut path.

Tommy

 

[Dauntless]

$17!!?! Or did you mean $170? Never occurred to me there'd be broken tinkertoy mowers out there. But there doesn't seem to be any near me right now.

You would be the one to make a frankenhooker mower. 8) .

Wouldn't a frankenhooker be more likely to have a chainsaw? At least in the movies. . . .

I want an electric mower so bad.

How about in Upland? http://inlandempire.craigslist.org/tld/4510886747.html

Hemet? http://inlandempire.craigslist.org/grd/4507846863.html

Eastdale/Chino? http://inlandempire.craigslist.org/grd/4503263996.html

Or somewhere, it's just $20 but I don't think it's cordless. http://inlandempire.craigslist.org/for/4506293918.html

The upside is I don't miss the recoil starter. The downside is the damn power cord. With a cordless the batteries will create issues, until such time as we get the super battery. Nothing is perfect, but I sure do like casually lifting and carrying my electric, when necessary.

 

[etard]

OK, I did the maiden cut after a fresh charge and I didn't get 2 perimeter rounds before I gave up, dang thing kept popping the breaker! I then opened her up, bypassed the key and found some Lipo puffy packs to ride on the thing. They are 6S so it should be the same RPM's. I had already finished the job with my gasser, so maybe next weekend, I'll give it a shot. The motor is a 350 Watt just like this:

http://www.ebay.com/itm/141085114191?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I don't know how they think 1/2 HP is enough, when the average gas mower is over 5 HP. They coulda put another battery on there and given it better power, it's so freakin light!

 

[Tommy]

I don't know how they think 1/2 HP is enough, when the average gas mower is over 5 HP.

etard, the manual recommends a cut speed of 2.2Mph, I'v found if you go slow and cut each week, it does just work.

with two 55Ah SLA I get about one hour run time with my three mowers.

I have not tested it, but I would think if you did not mulch the grass you would have more power to cut.

Tommy

 

[dogman dan]

Maybe it's overheating because the brushes got damaged. Seems odd to me it would overheat fast on 24v lead. It will overheat faster if it's lugging though.

I just have to think frankenhooker when hear of a radio controlled mower. In the first ten min the fiancé is chopped up by the mower.

 

[Dauntless]

A gas lawnmower says 5hp because it's around 80cc. It might actually make it up to 2hp if you wind it up. People mow their lawns around 1.2hp at the engine speed.

I wonder what they rate hp for a pushmower at. 1/4hp? People mowed lawns with those for maybe a century. I suppose there's still a few out there.

 

[etard]

It wasn't overheating and the motor didn't feel very hot to the touch, it was popping the breaker because it would get bogged and then save itself. The blades were sharp, I was moving at a snail's pace, but the deck height was a notch lower than my gas mower. I only need it to run for about 25 minutes, so range shouldn't be an issue if I can get enough power to chop like the gassers.

 

[edcastrovalley]

A gas lawnmower says 5hp because it's around 80cc. It might actually make it up to 2hp if you wind it up. People mow their lawns around 1.2hp at the engine speed.

I wonder what they rate hp for a pushmower at. 1/4hp? People mowed lawns with those for maybe a century. I suppose there's still a few out there.

I don't know how they come up with these horsepower numbers. I know the guys that covert their gasser cars to electric typically remove a 100+ hp engine and drop in a 20 hp electric motor and end up with more starting torque and a little faster acceleration than before.

I figure the way they compute gasoline engine horsepower is to wind up the rpms of an engine to the point where it's 1 rpm below a nasty, violent explosion then dump the clutch and measure that force during the few initial nanoseconds before the clutch explodes and catches fire.

 

[edcastrovalley]

I am wondering how hard it would be to gut a rumba vacuum and use the computer guidance on that retrofitted onto this motor.

Hmmm, that might just work. The Rumbas have a front bumper that springs in when it runs into something like baseboard molding so if your yard is fenced or walled off the Rumba (or mower) should back up and spin around and go mowing off in a new direction.

 

[dogman dan]

Oh, I thought the breaker on those motors popped when the motor overheated. I thought it was thermal. Used to pop em on table saws all the time, and invariably the motor was hot as hell when it would happen after lots of hard cutting. Go smoke a doobie, eat a ding dong, come back and the saw would be ready to run some more.

On my mower, the breaker will pop faster if I up the voltage, so I didn't think it was amps related. More volts, I would have thought the amp spikes would get less. I thought it was just overheating from the extra volts on brushes, arcing away. At 36v, it will start popping the breaker with very little load.

As for load, a 60-80 amps spike seen on a wattmeter is not at all unusual. Another reason never thought the breaker was amps related. A brushed motor with no controller will pull an incredible spike when you load it good.

I guess you were just mowing some really thick tall grass. With my B&D, I can't go 10 days. Even 7 days can be hard. 5 days ideal for my particular lawn. Or raise it, mow, lower it mow again for really tall grass.

It's definitely wimpy compared to a good 5-6 horse snapper. But so easy to push around the yard with 20 ah of lipo aboard, I don't mind mowing twice a week at all.

 

[tomjasz]

The healthiest most weed free lawn will be mowed every 5 days and NEVER shorter than 3" unless it's bermuda or such. All fescues, blues, and the like prefer frequent and 3" heights. If more folks read the seed label...

 

[Dauntless]

I don't know how they come up with these horsepower numbers.

Any utility engine on your mower, power edger, etc. is called 1hp for every 16cc, a 100cc would be called 6hp. The 49cc mower was common for decades and was called 3hp. It peaked at about 1.6hp if you revved it all the way up, it mowed the lawn probably under 1hp.

On your car, they have an outside agency certify that it puts out AT LEAST the hp rating, though recently Chevrolet wanted the Camaro upped to top the Mustang and didn't change a thing, they just got the higher rating confirmed. That too is with the engine wound up, nobody drives pushing the RPM near 7,000, etc.

So your electric motor might be giving the 20hp continuous, maybe it maxxes at double that. The 100hp engine that gets 35mph on the freeway is only generating maybe 40hp as it does so. If you build half the engine to strain 40ph from that it'll wear out sooner, so instead you have a bigger engine that's comfortable doing what's asked of it. I've heard the various analysis and have yet to see a clear answer, but instead of 750w there's supposed to be a better comparison to think of 300w of the electric motor to every hp of the gas engine, in terms of throttle response. Relatives in a business using both gas and electric carts say the gas works better overall, l'm not sure that it's not because the old lead acid batteries are getting dicey.

If you have an air cooled 4 cycle engine running at 20hp, you'll use about a gallon of gas in an hour. Liquid cooled doesn't evaporate as much unburned gas for cooling and therefore could run an hour at 33hp on one gallon. I don't have a reliable number for diesel, claims vary, but it's higher.

If you have a Honda Rebel, with an air cooled 17hp engine using pretty much all of that at freeway speed, you're getting over 75mpg, using less than a gallon in an hour. You could resolve cooling issues to double the mileage at the same horsepower and still not use up half the potential of the gasoline.

 

[etard]

Dogman,
You may be right on the breaker popping. I just thought it was the amp load from bogging, but the breaker was warm when I pulled it out so maybe it is some sort of thermal overload breaker. Either way 350 watts is not gonna cut it for my grass. Another possibility is the actual key might be wore out from thermal loads.

An external cooling fan could be on the list of add-ons for improving the mower. I need to make this work for cutting grass once a week. I don't have the time or desire to cut the grass more than every week or 2.


I don't know Daunt,

You are throwing out some crazy math there. First off, I'm pretty sure the Honda Rebel would NOT get 150 MPG if it was liquid cooled. Secondly, there are actual Gas motors that live up to their rated HP (Honda comes to mind), they just cost twice as much as the Murray I currently have.

 

[dnmun]

i would expect that raising the voltage would increase the current through the motor. it does not have a controller to regulate the output voltage of the controller. the breaker is just there to protect the motor from overheating so just take it out and see if the motor smokes.

 

[Dauntless]

I don't know Daunt,

You are throwing out some crazy math there.

Nope. Nothing crazy about it. It's the standard, basic rule of thumb. (Ooops.) You could go ahead and learn about it if you like. Why do you admit you don't know then say it anyway? http://www.epi-eng.com/piston_engine_technology/thermal_efficiency.htm

First off, I'm pretty sure the Honda Rebel would NOT get 150 MPG if it was liquid cooled.

Again, nope, you're not sure at all, you're just throwing that out there. You're not even sure what I wrote, because I said NOTHING about a Honda Rebel getting 150mpg if it was liquid cooled. All in your imagination. If only you had already read the link above and learned about how right I was. . . .

 

[etard]

You could resolve cooling issues to double the mileage at the same horsepower and still not use up half the potential of the gasoline.

OK, I must have read that wrong, upon first reading it sounded as if you thought a well cooled Honda Rebel could get DOUBLE the MPG. I think I understand what you are saying about the potential energy of gasoline,but I am not sure any of that applies to this situation. And you're right, I don't know what you are saying because this analogy made very little sense:

So your electric motor might be giving the 20hp continuous, maybe it maxxes at double that. The 100hp engine that gets 35mph on the freeway is only generating maybe 40hp as it does so. If you build half the engine to strain 40ph from that it'll wear out sooner,

 

[Mr. Chips]

I just inherited "That #$%#$% thing" from my neighbor. No charger, but batteries are still holding a charge, and motor won't spin.

Already diagnosed it as motor brushes. Are they available anywhere for this motor? Couldn't get the caps to unscrew (they chipped), so I'll have to break out the left-handed drill bits to do the job. Since I couldn't get them out, I can't see the brush size / part number.

One charger and a set of brushes and I'll have a nice little mower to give a pal who just got a home with a TINY lawn. Perhaps he'll trade me his McClane so I can have another 2.5HP B&S cutie engine for use as a propane-fueled generator!