A green friend (yes, I do have a few) is about to buy a battery electric strimmer to replace his petrol one, on the basis that it will result in less CO2 being generated.
I am sceptical, but has anyone already explored the arguments, to save me the time and trouble of trying to work it out?
I'm not sure of the CO2 balance, but surely a battery one is nicer to use in that there's no heavy and loud engine, no fumes and no winterisation needed?
I can't see a reason to buy a petrol unless you need to run it for hours, which not many domestic situations call for.
(If you're already invested in a tool battery system, you might be able to use pre-existing batteries so their cost doesn't come into it. At that point I'd expect it to win on the CO2 stakes)
Theo
It probably is marginally better. 2 strokes are not the most efficient brutes .a gas power station is.
He may find the battery one a bit limiting if he expects to run it for hours on end like a petrol one. OTOH you don't get gassed with two stroke engine smoke so there is a positive side to an electric strimmer.
I'd probably go for a mains powered one if I had to replace mine. By far the most annoying thing about strimmers is how often the autofeed on the strim line fails to feed properly and results in a jam.
Unless it has two battery packs he will spend most of his time waiting for it to recharge.
I think the main benefit mostly avoiding engine fumes rather than CO2. Basically all the other nasty smelly rubbish in its exhaust gasses.
The local authority sent a couple of chaps along on their diesel council lorry to strim an area about 10m by 20m.
The council, being greenish, had issued them with battery strimmers and four batteries each.
Two hours of strimming and they had run out of battery power.
So it was diesel lorry back to the depot, where there was a 2 hour queue for the four chargers, intended for the 80 batteries supplied.
Then it was lunch time.
Back in the afternoon in the diesel lorry to finish the job.
One chap is reported to have said that had they had their old petrol strimmers (which are more powerful than the battery ones) they could have done a second job that day, instead of the one job they got done.
Somewhere in the local authority a box has been ticked…
There are 4-stroke strimmers around, I have one.
On Monday, 17 October 2022 at 17:33:06 UTC+1, Chris Green wrote: trimmer.
Yes, I've got a nice Honda.
Bill
I used to have a 4-stroke hedge-trimmer; damned heavy it was!
I made the mistake of buying a 4 stroke Ryobi power head once... loathsome thing got lobbed in a skip in the end!
horespeower for horsepower a 4 stroke tends to be about 80% heavier
Locally yes, but what about power generation to charge it vs how much the oil refining costs, and what about the life expectancy of batteries and their costs? Brian
Some people are almost addicted to the smell of a 2 stroke, but is there any valid reason why they make them 2 stroke?, I would have thought a small diesel or four stroke might be both less noisy, more efficient and cleaner.
As for the feed, well yes this does seem to be an issue with all strimmers when I could see to use one. You definitely needed several batteries when first came out, much like vacuum cleaners, but these were either ni cad or dryfit lead acid in those days, unless you count the toy Black and Decker ones which were ok for ten minute tidy ups. Also I was surprised by how much more power petrol ones had over electric. Even if the so called horse power was the same, it seems there is a certain more beneficial stall performance with petrol over the electric motor. Maybe they have improved this now, by the motor control or ability to draw more current from the cells. Brian
We have two battery strimmers plus a 2 stroke . One of the strimmers is an 18v Bosch the other is a Husqvarna. We already had Bosch batteries and chargers for the 18v and same for the Husqvarna strimmer which my son bought. The Stihl 2 stroke hasn't been used since the arrival of the battery jobs. For small jobs the Bosch is used. No frustrating attaching the strimmer head. No starting procedure and it automatically advances the line each time it starts. Fair beats pulling out the Stihl split boom job, and starting it up, and its much lighter and easier handled. No it doesn't have the power of the Stihl The Husqvana is in a different league to the Bosch. More substamtial and runs for ever We have spare batteries for both Bosch and Husqvarna but don't find it necessary to swop them out very often. The garden is 1 .5 acres in size and has plenty of beds and paths so the strimmers get a good workout.
Diesel, much heavier, noisier, smellier. Low power to weight ratio. Expensive to make.
4 stroke, lighter, quieter but not as powerful as 2 stroke. Expensive to make, but cheaper than a diesel.2 stroke, light, powerful, noisy and smelly. Cheaper to make than either of the above.
For any motorised tool that you have to carry, a 2 stroke usually always wins on cost and power to weight ratio.
I’ve used two stroke and four stroke strimmers and whilst the Honda engined ones are nice and quiet, they definitely lack the “oomph” of a similar weight 2 stroke.
Tim
Brian Gaff snipped-for-privacy@gmail.com wrote:
You're studying the wrong gas, when it comes to small petrol engines.
Two stroke engines, pollute more than large block modern cars. They emit NOx much higher than the family car. There is no three-way cat on the output. A three-way cat requires stochiometric operation of the engine.
A three way cat removes:
VOC (waste petrol, large qty is a problem) NOx (remove oxides of nitrogen) CO (converts carbon monoxide to CO2, avoid poisoning)
A petrol strimmer is a pig. An absolute petrol pig. Your car is a champ, by comparison. At least it's only a GHG emitter, and not filling London with smog like a petrol strimmer would.
A four stroke engine, is cleaner than a two stroke. (Oil in separate compartment ? Not mixed into petrol 50:1 ?) Some lawn mowers are four stroke, and that's a step in the right direction. It's the two stroke engines (oil fumes and all), that have to go. Your riding lawn mower could be a four stroke.
Petrol strimmers would have a place, if the designers cared enough to clean them up. But, they don't. That's why they have to go. It's not some CO2 issue. The issue with strimmers was there, before we got into a tizzy about CO2.
The tank on a petrol strimmer is weenie in size. You can strim half the day, on that little tank. Squeezing the trigger and filling the air with oil fumes, every time you goose the trigger. The CO2 contribution from that weenie tank, is weenie (compared to the petrol your Escalade just used). Your Escalade is 300 HP. What's the weenie strimmer in terms of HP ?
Professional trimmers should carry the battery pack on their back, in a rucksack. This improves the mass of the strimmer and reduces arm strain. I saw some devices at the store, where the battery you were expected to use, throws off the balance. I don't know how long this battery would last, but I bet it's a while.
My strimmer runs off mains... but I'm just a hillbilly.
One thing you should know about mains strimmers, is they can overheat. My mains voltage is at the top end of the band, and I actually need the resistance of a "flimsy" mains cord, to prevent the strimmer from overheating. Conventional advice is to "always use a heavy cord", but this ignores the fact that some electric companies don't know how to run a grid. If you know your voltage is high, use a resistive mains cord to drop it a bit. (Nobody can afford an autotransformer to fix this.)
I was not expecting that to happen, but when I stopped strimming and picked up the unit while using the new cord, I could feel the extra heat coming from the vents on it. Not good. Normally, there is no heat to speak of. No smell that something is melting. I'm back to a thinner cord now, and it's fine again.
Paul
Me too but a mate melted the plastic cam.
Only consolation is the attachemts seem to fit my stihl hl75.
There is a hybrid that is supposed to avoid exhausting un-burned hydrocarbons, though it still needs lubricating oil in the fuel, the Stihl 4mix. This is a 4 stroke that with valves uses the crankcase as a scavenger/supercharger. It has a distinctive exhaust note.
A problem with operators holding them on full throttle against the electronic ignition cut off seems to negate the pollution advantage.
Plus a big advantage of 2-stroke for things like strimmers, they work any way up.
Brian Gaff snipped-for-privacy@gmail.com wrote
Only you poms.
Yep, much simpler and lighter.
But much heavier and more complicated.
I think the plastic components are one of its major flaws - it seems to be impossible to tune the thing to work reliably or even stay in tune. I found after a few moths use it would not run well, and conk out frequently - usually just changing the angle or position was enough.
Yup, I got a Stihl Kombi power unit to replace it. One can fettle most accessories to run on that.
(I did replace the trimmer head with a real Stihl one in the end after the Ryobi one disintegrated in use, flew off at speed, went through a gap in slightly open the patio doors, and narrowly missed hitting my son on the head!)
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