Battery Powered Lawn Mowers - All Junk - Why?

I read in sci.electronics.design that Spehro Pefhany wrote (in ) about 'Battery Powered Lawn Mowers - All Junk - Why?', on Tue, 26 Apr 2005:

My mower has a 2.5 HP Briggs and Stratton engine and yesterday was the first time I had to fix a fault other than due to old gas that wouldn't fire. The air filter was blocked with gunge and the engine was running far too rich.

The mower is 22 years old.

I read in sci.electronics.design that Spehro Pefhany wrote (in ) about 'Battery Powered Lawn Mowers - All Junk - Why?', on Tue, 26 Apr 2005:

You obviously cut the grass too often. Or do you own a prairie?

I don't post very often on any forum. What usually happens is I think of some idea or question and by the time I sit down to type the actual message my brain power (such as it is) has been redirected to something else.

I'm very happy and surprised so many of you are interested in this topic.

Batteries have always been 80% science and 20% alchemy. I'm sure many of you have read about the primitive batteries found in the ruins of several ancient civilizations. They usually look like a cup made of stone with a metal rod stuck in the middle. Anyway, us humans have been experimenting with batteries for a very long time!

Batteries have been the biggest curse and blessing of every circuit designers life. I can't remember how many times I breadboarded a circuit with a certain battery in mind. Every component had to be chosen with extreme care so that in end the selected battery would be adequate for the job.

Maybe in the next few years there will batteries (or even some kind of fuel cell) that will allow for the construction of a really good battery powered electric mower. It's always nice to dream a little, even if you're not a kid anymore.

You miss the point. It's automatic. And contains its own wire splicer :)

Existing petrol ones do this, owing to a nasty tendancy to explode if they don't. I suspect that if you really wanted to optimise for energy use, taking a petrol mower, and replacing the engine with a motor, and the fuel tank with a battery is a bad plan.

Especially if you're automating it, and the time it takes isn't so important. Take the speed way down, and go with a more shearing action, rather than trying to beat the grass into submission with a bluntish blade going at thousands of RPM. Of course, as you drop the cutting speed, you can decrease the damage that happens when you hit a rock.

Hello Spehro,

That will make for some nice furrows in the lawn. Unless you also throw in monster tires which can add another few hundred.

Regards, Joerg

I think I was overtaken by one of those on the M4 last week!

That was me in my Skoda Fabia Terry.

Didn't you see the hand waving at you? :-)

I read in sci.electronics.design that Spehro Pefhany wrote (in ) about 'Battery Powered Lawn Mowers - All Junk - Why?', on Tue, 26 Apr 2005:

I found the hard way that *fresh gas* is ***essential***. It's surprising how gas 'goes off' after a month or three in the tank.

Yes, I've rescued several. One (electric hover) is on its third owner after the Lazarus job! It needed one nut and bolt, two washers and cleaning out.

Best regards, Spehro Pefhany

Here's a picture of a battery+inverter+electric snowblower lashup:

-jiw

I read in sci.electronics.design that Frithiof Andreas Jensen wrote (in ) about 'Battery Powered Lawn Mowers - All Junk - Why?', on Wed, 27 Apr 2005:

Well, obviously that provides scope for a 'brrrmm-brrrmm' add-on for electric mowers. Requires a 555, a 741, a PIC and a flashing LED. Must run from a thermocouple supply; 1.2 V at 1 A.

Electrolux does.

The Internal Combustion Engine is what makes the Male Teenager cut the Lawn - The feeble whine of an electric mower is too Sissy and make him feel like a shandy-swilling Poof.

When I had one of those, Wife would cut the lawn or force Me to do it, and have me bag the stupid grass cuttings and take them away!!! As it happens, the electric soon dies from a missing filter causing the engine to suck in dirt and seize ;-)

So, having learned the Hard Way, The New petrol mower pulverizes the grass by design so there is Noting that can be picked up!!!

What We Want, No??

But isn't that the 5.5 HP model?