lawnmowers? Are they all crap?

[dmc]

I've been perfectly happy with the performance of the Flymo we had - it cut the grass fine for us. I'm just reluctant to replace like for like as the build quality was crap. Scarily so. A bit of hunting around seems to turn up plenty of others claiming this generation was crap (motors seem keen to let out their magic smoke) and also plenty of people reporting the bosch is good. I think I'll go for a Rotak which appears to get good reviews (yes, it's still an electric mower but we don't all have multiple acres to boast about on here).

Can't find out if it has an induction motor - which suggests not I guess. It apparantly has a Bosch "PowerDrive" motor. No idea what that means (beyond marketing cobblers) but apparantly it's a "hi-torque motor" and "With the Bosch Powerdrive system, power is at its greatest at low speed. If the blade speed is reduced, the power increases automatically"

Sounds great. See you all on here is 2.5 years time bitching about crap bosch mowers :)

Cheers all.

Darren

[Steve Firth]

The more important thing with a petrol mower is how easy they are to use compared to the electric ones. I can only guess that you're keen on electrics because you've never used a petrol mower. If you get a chance, before you buy another elctric, try using a petrol mower.

BTW, if it's misplaced "green" sentiments that make you want an electric, think again. Or at least think about where the electricity comes from.

[Andrew Gabriel]

That's an excellent description of a universal motor.

I think all uncontrolled motors do that, automatically.

What you really care about is the torque profile. An induction motor has high torque up near its free running speed, which means it keeps running near its freerunning speed when under load. Conversely, it has low starting torque, but that doesn't much matter (can be considered a safety advantage). A universal motor has high torque when it's significantly slowed (and highest when stalled). Actually, you have to reduce its speed to get any power/torque out of it, and thus the speed will drop considerably as the load increases.

Yes, the power consumption is greatest at low speed (stalled, in fact), but so what? Your primary concern is the torque at high speed.

Another benefit is that an induction motor is about the right speed to be direct drive, whereas a universal motor is going to be too fast and need some gearing down (except maybe on a really tiny mower?), which is extra complexity.

TBH, I really struggle to see why they bother making universal motor mowers. I can only imagine it's because a universal motor is something guaranteed to wear out (brushes), which gets repeat sales. I've heard universal motors are cheaper, but I can't see why.

One thing with both my induction motor mowers - when new, they had a feature which stops the motor very quickly when you release the handle. That died in both cases in about a year, and they just freewheel to a stop now. I'm not too sure how you do electric braking with an induction motor. With a universal motor, you just apply a resistance across it, or short it and use its own resistance. I do have some mains induction motor control boards which do electric braking, so I must go and look at how they work. They generate quite a hum from the motor when braking and they don't do it by reversing the motor, as it stops (and continues humming) without going into reverse if you keep the brake on.

[dmc]

No, I've used many many petrol mowers. I've also serviced plenty when I worked at a garage. Petrol is pain as I have to store a can of it somewhere. That somewhere is in the same shed as all the kids toys etc etc. Just can't be arsed. An electric that does what I want will be fine. It's not a huge garden. I hate mowing. SWMBO will only use an eletric mower. We all win :-)

nope, not in the slightest.

Darren

[dmc]

I thought as much :)

The Bosch seems to get the best reviews out of the "crap" end of the market that I'm looking at. I'll pick one up and see how it goes. Shame, having just ordered 800 quids worth of wood for my decking I was hoping to pick up a sliding mitre saw but I'll spend that cash on a mower now :-/

Darren

[Man at B&Q]

Seconded. Much better than the Qualcast it replaced.

MBQ

[Andy Champ]

Steve, we don't all have acres.

My rule of thumb is - if the original cable reaches across the lawn, electric is fine.

Oh, and I prefer rotary. Less servicing. Especially - if you run over something in the grass it doesn't need the blades resetting.

Andy

[Steve Firth]

I didn't imagine that everyone did. However when I lived in a semi I still found petrol mowers to be better than electric ones.

If it works for you. I found that the cable was just a PITA.

[Tony Bryer]

We know where it comes from, but I would have thought that the average B&S side valve engine probably has an efficiency way below most car engines, and probably below most power stations.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:

Got a contact number for this bloke? Used ride-ons here are extortionately priced and I wouldn't mind collecting one from there next time I'm over.

[A.Clews]

Thus spake Steve Firth ([e-mail]) unto the assembled multitudes:

I have to say that that hasn't been the experience of my GF, who professes to be very happy with her mower.

[The Natural Philosopher]

Side valves are not necessarily less efficient, just less good at high revs. Also mowers tend to be operated at constant throttle, so optimising a simple carb for that is not too hard.

[Dave Liquorice]

Er, constant speed. The "throttle" lever on a mower is really a speed setting control. The actual carburetor throttle varies with the load on the engine to (try to) maintain that constant speed.

[Andrew Gabriel]

The B&S I had auto adjusted the throttle to attempt to run at near constant speed with varying load. It used the air outlet from the engine cooling fan to move a spring loaded vane, to measure the speed. This can't match the speed to the load as well as an induction motor mower, but it will do a lot better than a universal motor mower.

[Appin]

The message from The Natural Philosopher contains these words:

Fairly cheap, then.

Just bought a new Stiga mid-range model -- paid £5200 for it. RRP well over £7000.

Paid a couple of grand about ten years ago for a Countax which is still running but the grass box is falling to pieces and the deck lift motor doesn't work. The deck has been rebuit once with new pulleys etc . Stiga is considerably more robust.

[Appin]

The message from Harry Bloomfield contains these words:

That's about the minimum power that it's worth buying in a ride-on. Though for the half-acre our house sits in it's not worth using a ride-on -- too many ups and downs and fiddly bits. The ride-on gets used for areas outwith the front garden.

[Appin]

The message from Jules contains these words:

It's a fact that in the US such things are cheaper. However, there are a couple of points to bear in mind

1. There's a wider range of mowers on sale in the US and some of the small ride-ons in the US are desperately underpowered
2. US mowers tend to be simpler and designed to deal with typical US grass -- put them on typical UK grass and they choke up rapidly on the thick, lush growth.

Mowers for use in the UK generally need much more sophisticated grass-handling mechanisms if they're going to gather the grass effectively. I've cut lots of grass both in North America and in the UK. Vivid memories of an American tractor with a cutting deck with just one huge blade with lifters on the end which were supposed to create enough lift to propel the cut grass into the grassbox. Sometimes worked when the blade was brand new, the grass was very dry and short. But the lifters invariably broke off on a stone and without the grass collection system in position the thing could propel stones with a velocity that seemed to approach that of a bullet, with somewhat interesting effects on the first object it hit.

Some pretty good bargains to be found in the US among motor mowers around $99.99, though. Crude -- but they work quite well, at least in their target market. No pun intended -- I didn't say Target :-)

[Appin]

The message from Jules contains these words:

That is indeed the problem -- lack of stability. And that goes for a lot of the cheaper ride-ons as well. Last ride-on we had to change the tyres to get a decent grip.

New Stiga is 4WD.

[Appin]

The message from [e-mail] (Steve Firth) contains these words:

Not using an electric at the moment, but looking seriously at lithium-ion battery powerd one for the holiday cottage and for another remote building. Some of us have a 20 mile round trip to get petrol. Many places won't let you buy more than a few litres at a time and demand all sorts of fancy markings and labels on the can and generally are out to make life difficult. And electric motors start first time every time, which is more than can be said for petrol mowers of which I've had dozens -- literally -- over the years, on two continents and with assorted engines, by far the worst of which was a Tecumseh-engined Mountfield with regard to which the best that could be said was that the application of a hot-air gun to the cylinder head usually made it possible to start the thing. And yes, the choke did work. Even a Honda

-- one of the older, Japanese made engines, too -- was a poor starter, in spite of the fact that my Honda motorbike which did NOT have an electric starter, was a "first kick every time" starter from cold, once you learned the very precise technique for so doing -- full choke and 90 degree twist of the throttle if the engine were even slightly less than hot. Hassle is something we can do without, so non-petrol power isn't necessarily crazy. It's not practicable in every location, though.

[Steve Firth]

You could buy a proper tractor + mower of your choice for that money.