Lawnmowers

Sterlingtimes

Corded electric lawnmowers are measured in Watts, e.g. 1800 Watts.

Cordless mowers are sold in Volts, e.g. 40 Volts or 2 x 40 Volts. Batteries are often quoted in Amp Hours, e.g. 2AH.

How would the cutting strength of an 1800-watt corded mower compare with that of a cordless mower with 2 x 2AH batteries?

victor2

Sterlingtimes said:

Corded electric lawnmowers are measured in Watts, e.g. 1800 Watts.

Cordless mowers are sold in Volts, e.g. 40 Volts or 2 x 40 Volts. Batteries are often quoted in Amp Hours, e.g. 2AH.

How would the cutting strength of an 1800-watt corded mower compare with that of a cordless mower with 2 x 2AH batteries?

You can't really compare them, any more than you could compare the "cutting strength" of a 1500W mains powered mower to an 1800W one. So many other design factors affect how the mower actually cuts the grass.
A 40V battery delivering 2amps for 1 hour is providing 80 watts for that hour. A 1800W mains powered one can provide 1800 watts for as long as it is running.
So, the battery one has 80/1800, or 4.4% of the cutting strength? Meaningless numbers unfortunately.

Sterlingtimes

victor2 said:

You can't really compare them, any more than you could compare the "cutting strength" of a 1500W mains powered mower to an 1800W one. So many other design factors affect how the mower actually cuts the grass.
A 40V battery delivering 2amps for 1 hour is providing 80 watts for that hour. A 1800W mains powered one can provide 1800 watts for as long as it is running.
So, the battery one has 80/1800, or 4.4% of the cutting strength? Meaningless numbers unfortunately.

Thank you. So could corded mowers work well with 80 Watt motors?

PHK

All things being equal they could. 

Remember that as well as design differences the 1800w is the power consumed not the power output. 

Corded mowers tend to use less efficient motors. As there is no agreed measure of how well a mower cuts (there's no such thing as standard grass for example) and everyone's idea of what a mower should do is different (some want a short neat cut others just want to speedily get rid of long grass) then manufacturers can choose which characteristic is the selling point. 

So someone that needs a cordless mower that keeps regularly cut grass looking nice will find a 40V cordless mower superior to a 18V cordless mower. But is likely to find a petrol cylinder mower even better that collects the clippings even better.  

Sterlingtimes

PHK said:

All things being equal they could. 

Remember that as well as design differences the 1800w is the power consumed not the power output. 

Corded mowers tend to use less efficient motors. As there is no agreed measure of how well a mower cuts (there's no such thing as standard grass for example) and everyone's idea of what a mower should do is different (some want a short neat cut others just want to speedily get rid of long grass) then manufacturers can choose which characteristic is the selling point. 

So someone that needs a cordless mower that keeps regularly cut grass looking nice will find a 40V cordless mower superior to a 18V cordless mower. But is likely to find a petrol cylinder mower even better that collects the clippings even better.  

Thank you for taking the time to respond. This is interesting. However, now that I understand the comparative power ratings, I feel disinclined to purchase a cordless mower. My father had a battery mower in the 1960s with a lead acid accumulator, possibly an ACTO.

TELLIT01

I would have thought 'cutting strength' is down to motor power and gearing rather than the battery.  A lower capacity battery will go flat faster but won't necessarily be any less effective when it is charged.

My thoughts have always been that a petrol mower would be more 'versatile' than a mains electric, which would be more than a battery electric.  By 'versatile' I mean able to cope with longer and/or wetter grass.  My neighbour had a battery electric mower which was great during the summer months to keep the lawn tidy, but next to useless in Spring when the grass was long and wet.

victor2

My feeling is that battery technology has to advance even further than the leaps and bounds it has made in recent years, before something like a battery powered lawnmower can be seriously considered for a typical domestic user.

Vacuum cleaners are getting there, but I still get the "real" mains powered unit out when our battery cleaner can't cope!

EssexExile

victor2 said:

My feeling is that battery technology has to advance even further than the leaps and bounds it has made in recent years, before something like a battery powered lawnmower can be seriously considered for a typical domestic user.

Vacuum cleaners are getting there, but I still get the "real" mains powered unit out when our battery cleaner can't cope!

My battery Mountfield handles my large garden just fine.

Blackjack_Davy

As a rule cordless battery powered have less power and by that I mean they have less "oomph". Its a compromise you could up the "oomph" but then the battery would run out a lot quicker. Terribly technical, I know. If you really want something with plenty of "oomph" but without a cord then get a petrol engine

PHK

Blackjack_Davy said:

As a rule cordless battery powered have less power and by that I mean they have less "oomph". Its a compromise you could up the "oomph" but then the battery would run out a lot quicker. Terribly technical, I know. If you really want something with plenty of "oomph" but without a cord then get a petrol engine

I don't think that's true. Battery mowers can supply a much larger current on switch on and so have more oomph. Corded motors tend to take a short time to speed up. 

Remember the power going in is being quoted not the output power 

victor2

PHK said:

Blackjack_Davy said:

As a rule cordless battery powered have less power and by that I mean they have less "oomph". Its a compromise you could up the "oomph" but then the battery would run out a lot quicker. Terribly technical, I know. If you really want something with plenty of "oomph" but without a cord then get a petrol engine

I don't think that's true. Battery mowers can supply a much larger current on switch on and so have more oomph. Corded motors tend to take a short time to speed up. 

Remember the power going in is being quoted not the output power 

But corded mowers keep running as long as there is mains power. Battery ones get slower and die - generally before you've finished the job.