battery lawnmowers

fryup

fryup wrote: »

so how do calculate watt hours into running time??

mine is 60v x 2ah = 120watt hrs (but the actual running time is 35 minutes'ish)

To get the running time you'd have to know what power the mower is pulling and the easy way to do this and one that might be pretty useful is to attach one of these at the motor controller, between the battery wires and controller. that's the silver box that looks like this.



The power monitor looks like this.

https://www.amazon.co.uk/Precision-Analyzer-Consumption-Performance-Backlight/dp/B07M5XD4G9/ref=sr_1_2_sspa?dchild=1&keywords=battery+monitor&qid=1624203742&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExM0JUMllOS1FYTlAzJmVuY3J5cHRlZElkPUEwMDMyNDkwWTEyNlFCVDBBMllaJmVuY3J5cHRlZEFkSWQ9QTA0MzUyMTAzRlVRMUtGSFpMRkxZJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

This voltage/power monitor will tell you exactly how many AH is being pulled from the battery.

But generally the voltage x ah = watt hrs, the more you have the longer the device runs, just knowing the Ah alone is useless, for example.

24v 5 ah = 120 Watt hrs

52v x 5 ah = 260 watt hrs

Other factors that might greatly influence battery run time are, higher internal resistance = poorer quality, basically if the battery is getting hot this is a key indicator of high internal resistance. High temperature might also cause the battery to cut out before all the energy is used, as the battery ages it will get hotter and hotter.

Try let the battery cool after fully charging it before cutting the lawn, then let it cool before charging it, higher temperature shortens the life of the battery, store in a cool location.

If the battery feels warm on the outside then inside the casing the actual cells could be hot to roasting.

Always try find a battery mower who's charger has a build in fan to cool the battery as it's charging.

Wildly Boaring

When batteries come out of the DeWalt mower they are roasting.
Always let cool before charging but did keep stored at 100% until recently

Darwin

The Ego chargers have built in fans and the batteries themselves have a specially designed casing to keep the cells cool. My fast charger failed inside warranty which wasn't great though!

Wildly Boaring

Wildly Boaring wrote: »

When batteries come out of the DeWalt mower they are roasting.
Always let cool before charging but did keep stored at 100% until recently

that kind of heat is certainly going to reduce the life of the battery a lot faster, if they're hot through the plastic casing imagine what the cells are like inside ?

Were they always roasting even from new ?

The batteries usually get warmer as they age and if they weren't as hot when new and they are hot now that's a clear indicator that internal resistance has increased a lot which is a clear indicator to aging.

It's also a good idea to let the battery cool after charging, even though it might not seem warm from the outside it could be warm inside.

Wildly Boaring

I've rarely noticed them hot using a drill or Skil saw. But with the mower yes I think they've always been hot.

Talking to my father about this today. He reckons one of his 2016 batteries is no use by now

Wildly Boaring

Wildly Boaring wrote: »

I've rarely noticed them hot using a drill or Skil saw. But with the mower yes I think they've always been hot.

Talking to my father about this today. He reckons one of his 2016 batteries is no use by now

Sounds like it's time to change.

Springwell

We've an Ego with a 7.5Ah battery, tackles 0.75-1 acre of long/rough meadow grass no bother in a charge (depends how wet/long, if left very long you need a charge for the last bit) Pricey though!

The good mowers with good batteries are usually pricey. But you don't have to worry about maintenance and they're much easier to start than a petrol mower + much lighter.

The technology is improving every year. The self propelled ones will be harder on the battery too.

If looking for a mower always look for higher voltage 36 volt minimum 52 volts or higher even better and highest Ah battery and fastest charger you can buy it's worth it in the long run.

TheBigGreen

Greenworks 80V FTW

TheBigGreen

TheBigGreen wrote: »

Greenworks 80V FTW

I just googled and saw an 80v 4 ah battery that's amazing, progressing much faster than I thought. That's 320 Watt hrs of storage which is twice that of some lower voltage batteries.

The thing about higher voltage is that they should run at lower currents meaning less heat which is always good, current produces heat.

So yeah, always go for the highest voltage you can, at that rate I'd say 52 volts should be the minimum these days of they have 80 volt batteries now.

fryup

thinking about getting a spare for mine, but can these batteries be sent over from the UK to a private address?? aren't they classed as hazardous material?

or will i have to order one through my DIY store?

fryup

fryup wrote: »

thinking about getting a spare for mine, but can these batteries be sent over from the UK?? aren't they classed as hazardous material?

Yes they can be sent but usually the courier has to be aware and might charge more but where you get the battery might not have this shipping service available .

greasepalm

Interesting read so might as well ask if anyone has replaced a dodgy cell in a power pack and sourced them to fit.

greasepalm

greasepalm wrote: »

Interesting read so might as well ask if anyone has replaced a dodgy cell in a power pack and sourced them to fit.

It's not so easy to replace a cell in a pack and in fact, I wouldn't do it because you have to make sure all the cells have the same internal resistance or they will only perform as good as the weakest cell and it's not going to be easy to match a new cell with an old, certainly a new cell into an old pack is not a good idea.

Springwell

Should have added ours is self propelled and the field is on the side of a hill! Takes a bit more out of it!

Springwell

Springwell wrote: »

Should have added ours is self propelled and the field is on the side of a hill! Takes a bit more out of it!

Yeah will take more out of it alright but bet you appreciate it on the hill !

I have a ride on and I couldn't imagine doing it with a petrol or electric mower on 1 acre, well that's including house and yard and still takes me around 1 hr or little more depending how long it is ( and how often my 2 Sons harass me for spins lol ) but before I got the ride on with the petrol mower, a good wide one, it was talking I think 4+ hrs because I had to empty the box so much it really wasn't practical.

Kaybaykwah

Darwin wrote: »

I have some Ego gardening equipment + batteries and while expensive it is excellent piece of kit for a larger garden. The batteries themselves automatically discharge to 30% if left unattended for more than 30 days so one less thing to worry about. The largest battery I have (7.5A @ 56v = 420 Watt hrs) is 3 years old at this stage and still runs for about 50 minutes.

I totally agree. I bought the Ego mower here in Canada 3 years ago, and it is very satisfactory, I haven't found any negatives, so far.


I hope I don't run into a charger problem like you did after warranty, though.

New Home

Any views on this one?

https://www.lidl.ie/p/great-gardens/1300w-electric-lawnmower/p12668

EDIT: Sorry, wrong thread, I've just realised it has a cable.

fryup

i have this one,

https://www.coopsuperstores.ie/Greenworks-Cordless--60v-Digipro-Lawnmower-With-2ah-Battery--Charger-1776950

first time i used it i got 35min running time off it, used it for the second time today and got 27min working time off it

am i doing something wrong should i charge it the night before i use it?