electric lawn mower

Post by **antiscab** » Wed, 11 Feb 2015, 05:41

For ages i used a battery powered electric lawn mower (ozito eco-mow 500) I scored off ebay for $20

it had 2 x dead 12v 20Ah batteries
I put 18 x nimh 30Ah cells in to replace
it was good, but required prior planning getting the nimh batteries manually charged
the nimh batteries were also only actually good for 15Ah, so I had to mow the front lawn one day, and the back the next.

by chance at the last verge side collection I was able to pick up an Eco-mate cordless mower, this one with no batteries

I used 8 x 60Ah Thundersky cells I have lying around, with an EV Power BMS

On the first mow, I only used 11Ah, to do both the back and front lawns.

Amazing the difference between wet and dry grass

If you are in the market for a battery powered mower - try your local verge side collection and put a big lithium battery on.
results are better than the commercial offerings that use 2.6Ah or 4Ah batteries

Post by **Faz** » Wed, 11 Feb 2015, 08:46

I have the same mower pictured. Bought it new. It comes with 24V of 12Ah lead acid (from memory) and would cover about 200sqm of my lawn on a single charge.
The plug in circuit breaker would cut out when the going got tough though, then take a while to cool down.

Website · Post by **Simon** » Wed, 11 Feb 2015, 17:01

I have the Ozito mower too. Swapped out the heavy lead acid pack and put in a lightweight RC Lipo pack that I also use on my electric mountain bike. I use 4x 22.2V 5AH packs wired in parallel. It's great! So light and easy to manouver.

Post by **Richo** » Wed, 11 Feb 2015, 20:20

I fixed the mowing problem by not watering

225m2 of desert wonderland...

Just got to find a way to fix the weed problem in winter.
If only it snowed in Perth

Post by **mikedufty** » Wed, 11 Feb 2015, 20:26

I got the Ryobi 36v mower without batteries and stuck 48v of Hobbyking LiPos I had lying around from an electric trials bike in there. Worked really well but the batteries died, not sure if it was the heat or the load of the mower or if they were already on the way out before I started putting them in the mower (they had started intermittently setting off the low cell voltage alarm on the bike already).

Post by **jonescg** » Thu, 12 Feb 2015, 01:27

LiPos don't like hot days, especially if stored fully charged. You would want a well protected, snug battery enclosure for them. I plan on mounting a 5 kW motor to my old mower chassis as soon as I find one.

Post by **carnut1100** » Thu, 12 Feb 2015, 04:09

I'd love to build an electric mower...But as I use it for my living I would need one that can do at least ffour large lawns on a charge....I'm often mowing for tthree hours or more in a day.

Post by **antiscab** » Thu, 12 Feb 2015, 04:36

carnut1100 wrote: I'd love to build an electric mower...But as I use it for my living I would need one that can do at least ffour large lawns on a charge....I'm often mowing for tthree hours or more in a day.

Ironically, my mower with 60Ah batteries could probably mow a lawn that size

with a 1500W TC Charger, could probably charge back to full in an hour too

Post by **GRMarks** » Sun, 17 May 2015, 00:57

I also converted an eco mower to Lithium cells. I used a ping battery pack. The pack is 24V 30ah, has built in BMS and overload cut out circutes and I got a 10ah charger with it as well. The original battery was 24v 10ah (2 sealed 12v lead acid batteries) and I got 5 years out of it. I can now mow the whole lawn using about 1/3 of the pack (10ah charger takes about 1 hr to recharge the pack). It seems to have a lot more power (now at 25.6v (3.2 X 8)). I disabled the thermal cut out because it is a pain, it cuts out on the first hint of a little load. I just make sure I don't work it hard for too many seconds.
I made a fibre glass cover for it so it looks a little more polished than the one above. The pack is also smaller so it was relatively easy to make a cover for. (compared to the 60ah thunder skys above).
I also have an old lawn mower base I rescued from a nature strip that I will convert into an electric mower. Given the the DC motor on the eco mower is 500w I think a 2kw motor would be heaps of power. 5kw would be over kill (unless you want a really wide cut). Brushless would be nice too.
Put it all together and you would have the worlds first $2,000 lanw mower that was not a ride on!

Post by **antiscab** » Sun, 17 May 2015, 01:33

I was thinking of making another one, but then I saw this lawn mower for sale:

Certa Battery mower

at that price I couldn't be bothered :p

Post by **GRMarks** » Sun, 17 May 2015, 21:19

One other thing I did was bend the backs of the blade up a bit more so it throws the grass a bit harder. It cuts wet or dry grass now with no problems. No clogging etc. The grass gets thrown right to the back of the catcher and compacted in a bit.

It looks like your eco mower has spent a lot of time in the sun! Mine is still a rich red colour. I keep it in the garage (out of the sun) when not in use.

Post by **Adverse Effects** » Mon, 18 May 2015, 01:14

you seen the new ones?

like the EGO and others

Electric lawn mowers

Post by **GRMarks** » Mon, 18 May 2015, 05:27

No, just followed your link and had a look just now. Looks good on the youtube clip, but then so does the eco mower, but in reality its only so so on power. But with the lithium battery mine is a whole new beast now. Its amazing the difference the change made.

I think you would need to test run it (the EGO) to see how it really is.

Post by **antiscab** » Mon, 18 May 2015, 06:42

GRMarks wrote:
It looks like your eco mower has spent a lot of time in the sun! Mine is still a rich red colour. I keep it in the garage (out of the sun) when not in use.

Mine was a side of the road special that had no battery
Didn't even know if it worked till I powered it up

Post by **GRMarks** » Mon, 18 May 2015, 18:17

An image is worth a 1000 words!

hmmm image not showing - I will fix it latter, have to go now.

Post by **carnut1100** » Wed, 20 May 2015, 01:41

Most of the electric mowers available are tiny ones for small backyards.
Im using a mid size mower with a 3.5hp motor and it is just adequate.
Shortly picking up my new mower which is a 19" cut with a 3 kW petrol motor....
I'd want at least 2kw preferably 2.5-3 and 3,000rpm.
Would want to run for three hours.

Post by **antiscab** » Wed, 20 May 2015, 05:00

how much petrol do you burn in a day using your new 19" petrol mower?

Otto cycle engine that size yields 1.5 - 2 kwh per L petrol burnt in that kinda situation - mainly because the loading is never optimal

interested to hear how much energy is needed to mow on a commercial basis

Post by **BjBlaster** » Thu, 21 May 2015, 04:54

My old girl is still going:

It's done 2 packs in 8 years

My Lawnmower

It sure beats petrol and problems!

Post by **Richo** » Thu, 21 May 2015, 20:54

That's an awesome job

I purposely never changed the oil in mine in a vain effort to make it blow up so I can do the same.
I have had it ~10 years now and the damn thing is still going on the same oil

Post by **BjBlaster** » Sat, 23 May 2015, 17:43

Cheers Richo,
It's been really good even though it's output is just over 300W. (It's a 500W 36V motor running at 24V with 2 x 9Ah 12V SLAs..) I haven't had any trouble cutting the lawn unless I leave it way too long or it's too wet, then you just have to go easy but it still works well enough that I don't need a petrol one

Sharpening the blades makes a massive difference!

Post by **carnut1100** » Thu, 01 Oct 2015, 01:45

Well, I never did get the new mower....I cancelled the order.
My old mower is still running well, but really heavy stuff slows it down.

I am seriously considering getting a 56v EGO and seeing how it goes...I really like the new Echo range of 58v stuff, but it isn't sold outside North America yet...