Help required with school assignment

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Workinkiwi
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Help required with school assignment

Post by Workinkiwi » Sat, 30 Dec 2017, 20:56

Hi there,
I’m new on here and have came to Ask for help and information for my daughter.
Her year 12 project for automotive is an old ride on lawn mower, that was kindly donated to her for this assignment. Besides looking old and tired the engine is the only thing that’s really stuffed.
I thought sweet this shouldn’t be to hard or expensive as she can rebuild it, but she informs me that they have told her this lawnmower needs to be powered by batteries and an electric motor.
They have said they want it solar powered and a built in charger but since I’m paying for this I don’t want it to be expensive. My daughter doesn’t work part time anymore as it was distracting and interfering with her school work, I want her to pass her HSC so she can get all the opportunities I never had.

Sorry for the long winded intro,

What I’m wanting to know is what sort of stuff do I need to buy for her to achieve this?

The motor needs to be able to spin fast enough to mow and slowly move the mower while mowing.

The mower has a hydraulic drive gearbox running off a pully, the cutting deck has 2 blades, these also run off a single pully. These were both connected to the bottom of the motor.
Will this set up work still or will it need changing?
Will it need a soft start?
What so of voltage will be required?
Due to limited space could 3 or 4, 12V 4Ah YTX4L-BS gel batteries do the job as they are only $32 on eBay.
Would that be 48V@16Ah?

Any help will be greatly appreciated as I feel she may have bitten off more than she can chew. She is the only girl in her auto class, got top student for year 11, now I’m hoping this assignment doesn’t push her to fail.

Regards

Dellas

antiscab
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Re: Help required with school assignment

Post by antiscab » Sun, 31 Dec 2017, 00:19

That is a bit of a project. It has to be that mower? Can't be swapped for a mower that is already electric but broken in some way? (usually the lead acid batteries fail first)

Assuming that's not possible, what size engine is presently in the mower? That will give you an idea as to peak power requirement.

As with all projects, cheap, easy, effective, efficient. Pick two.

Where are you located? I may have a shed full of bits that could help (lots of us probably do)

Getting a motor that can do both may be tricky, at least cheaply and light.

Can you get away with just on/off? Or do they want an actual throttle?

Cheapest batteries are probably salvage laptop batteries.
Easiest batteries would be lead acid or Nimh large format.
Most efficient and effective would be a lithium battery from a scooter.

Probably best to get hold of an electric mower and pinch parts off it.

Failing that, the hydraulic motor off a forklift might do it, but they tend to be a bit heavy

Ebike motors might be a bit small
Matt
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1999 Prius - needs batt

Workinkiwi
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Re: Help required with school assignment

Post by Workinkiwi » Sun, 31 Dec 2017, 06:44

Hi there,

We live in the hunter valley, NSW.
Yea we need to keep the lawn mower we all ready have.
I think it might be easier for her to use 2 smaller motors to drive the blades then a bigger 1 to drive it.

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4Springs
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Re: Help required with school assignment

Post by 4Springs » Mon, 01 Jan 2018, 18:13

Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
Hi there,
I’m new on here and have came to Ask for help and information for my daughter.
Her year 12 project for automotive is an old ride on lawn mower, that was kindly donated to her for this assignment. Besides looking old and tired the engine is the only thing that’s really stuffed.
I thought sweet this shouldn’t be to hard or expensive as she can rebuild it, but she informs me that they have told her this lawnmower needs to be powered by batteries and an electric motor.
They have said they want it solar powered and a built in charger but since I’m paying for this I don’t want it to be expensive. My daughter doesn’t work part time anymore as it was distracting and interfering with her school work, I want her to pass her HSC so she can get all the opportunities I never had.

Sorry for the long winded intro,

What I’m wanting to know is what sort of stuff do I need to buy for her to achieve this?

The motor needs to be able to spin fast enough to mow and slowly move the mower while mowing.

The mower has a hydraulic drive gearbox running off a pully, the cutting deck has 2 blades, these also run off a single pully. These were both connected to the bottom of the motor.
Will this set up work still or will it need changing?
Will it need a soft start?
What so of voltage will be required?
Due to limited space could 3 or 4, 12V 4Ah YTX4L-BS gel batteries do the job as they are only $32 on eBay.
Would that be 48V@16Ah?

Any help will be greatly appreciated as I feel she may have bitten off more than she can chew. She is the only girl in her auto class, got top student for year 11, now I’m hoping this assignment doesn’t push her to fail.

Regards

Dellas
I think you are correct - this is a big project! Does she have all year to do it? It's a bummer if you have to pay for the parts, but I guess you'd get a sweet mower out of it.
In Launceston our club members are helping the local year 11/12 school with a project. Hopefully your local club (NSW) might be able to do the same for you. You can find Mark's phone number on the NSW web page here: http://aeva.asn.au/nsw

Do you have a photo? And a brand/model would be good, it will help to work out how powerful the motor(s) need(s) to be. Also the operating RPM will be important to find out.
With a hydraulic drive I'd assume that it would be ok to have the motor go flat-out the whole time, so you might get away without a controller (soft-start). That will save some cost and complexity.
My guess without seeing it is that it will be easier to use just one motor to do both pulleys, the same as it was originally.
48V or 24V is a good target voltage, both are quite common and low enough not to electrocute people in most situations. See what motor you can find before you decide.
The way that the batteries add up is that 4 x 12V 4AH batteries would add up to 48V 4AH in series, or 12V 16AH in parallel. This would be enough to prove the concept, but my gut feeling is that it wouldn't run for very long with any kind of load. We'll be able to do some calculations once we know the power of the original engine.

Steer clear of the solar panels idea if you can. Or at least leave them until everything else is working, they are really a separate project. Solar panels are best installed on the roof of the garage in which the mower is stored! An onboard charger is not such a big deal though, a slow charger shouldn't cost much and will be fairly small.

Workinkiwi
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Re: Help required with school assignment

Post by Workinkiwi » Thu, 04 Jan 2018, 18:32

Hi guys, sorry for late reply been busy working.
Ill get all the pictures and information in the weekend.
Thanks

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Richo
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Re: Help required with school assignment

Post by Richo » Mon, 08 Jan 2018, 12:41

I'm still trying to get my head around that a yr12 Automotive student that hasn't started yet already has a project but isn't really automotive.

They want it solar powered :lol:
Even a 100W panel won't help you much.
Dreamers...

I'd think it would be cheaper to buy a standard electric mower than to try convert a ride on one.
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Richo
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Re: Help required with school assignment

Post by Richo » Mon, 08 Jan 2018, 12:59

Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
What I’m wanting to know is what sort of stuff do I need to buy for her to achieve this?
The motor needs to be able to spin fast enough to mow and slowly move the mower while mowing.
Sounds like a realistic objective.

Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
The mower has a hydraulic drive gearbox running off a pully, the cutting deck has 2 blades, these also run off a single pully. These were both connected to the bottom of the motor.
Will this set up work still or will it need changing?
Yeah this is where a picture may help.
It's possible.
Removing the hydraulic drive may make the conversion a bit harder.
Picture please...
Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
Will it need a soft start?
Depends on the torque of the electric motor.
It's possible a series DC on low voltage maybe ok without a controller or soft start.
Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
What so of voltage will be required?
Due to limited space could 3 or 4, 12V 4Ah YTX4L-BS gel batteries do the job as they are only $32 on eBay.
Would that be 48V@16Ah?
It's unlikely that 4 x 12V4Ah would be appropriate.
Why is there limited space?
Really it comes down to if the existing mechanics can work with a motor or if the drive and mow need to be separated.
A couple of pics and a few guru's here should be able to sort this out!
Workinkiwi wrote:
Sat, 30 Dec 2017, 20:56
She is the only girl in her auto class, got top student for year 11, now I’m hoping this assignment doesn’t push her to fail.
Failure is not an option here :geek:

In an ideal world I see a small Series DC motor with dual shaft from a scrap yard for like $10 and a half dead 12V car battery for free from an auto store.
A few wires, a phat ON switch, 12V car charger and a gimmiky 12V cigarette solar charger and your done.

It's unlikely to go that way but...
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Richo
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Re: Help required with school assignment

Post by Richo » Mon, 08 Jan 2018, 15:19

These 4.8kW 36V Series DC are pretty close.
Rip off the brake and you have dual shaft?!?
http://billsmachinery.com.au/product/dr ... ake-motor/
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4Springs
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Re: Help required with school assignment

Post by 4Springs » Mon, 08 Jan 2018, 17:13

Richo wrote:
Mon, 08 Jan 2018, 15:19
These 4.8kW 36V Series DC are pretty close.
Rip off the brake and you have dual shaft?!?
http://billsmachinery.com.au/product/dr ... ake-motor/
Any idea what RPM those would do Richo? The power looks good as an approximation before we get any actual specs.
His first post suggests that a dual shaft is not required, both pulleys were "connected to the bottom of the motor".

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Re: Help required with school assignment

Post by Richo » Tue, 09 Jan 2018, 12:44

Bills has crashed so I don't know - I'll check later.

In any case not so close to NSW for Dellas to buy - there probably is a machinery scrap yard in NSW that would be better.

eBay item 253352394091 is about 140km away and after $50 for a motor for $150 for the lot.
I'm a bit skeptical about these being DC motors as the last pic looks like a bank of 3-phase controllers.
Two of the motors appear to have a gear reducer and wheel hub attachment.
Also a bit over powered at 14kW for a mower - as the title says suits car conversion.

For something new there always is the ME0909 with 48V 5kW continuous.
http://www.evworks.com.au/motenergy-me0 ... tor-5-15kw
In stock but at $524+shipping may be out of the budget for this.

Also Re the phat ON switch it may have to be a contactor with a small switch.
Which would mean you either need a separate 12V AUX battery or keep the whole system at 12V.
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Re: Help required with school assignment

Post by Richo » Wed, 10 Jan 2018, 12:48

Richo wrote:
Mon, 08 Jan 2018, 15:19
These 4.8kW 36V Series DC are pretty close.
4Springs wrote:
Mon, 08 Jan 2018, 17:13
Any idea what RPM those would do Richo?
Yeah crown don't publish their motor specs - not surprising.
Based on other similar function motors they are around 2,000RPM.
And that comes down to load and voltage.
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Re: Help required with school assignment

Post by Richo » Wed, 10 Jan 2018, 12:59

ebay 162812668959 $21 for a contactor
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Re: Help required with school assignment

Post by Richo » Wed, 10 Jan 2018, 12:59

The next thing down from the fork/walkie motors are the electric pallet jacks these range from 1.5-2.5 kW.
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Re: Help required with school assignment

Post by alexeiw123 » Fri, 26 Jan 2018, 11:25

What an assignment!

I've got a bunch (36x) of CALB SE130Ah cells in Port Macquarie, that came out of a conversion as they were end of life for pushing a full sized car around. After measuring internal resistance, the worst ones were set aside and the remaining set up in pairs ready to be strapped up, to balance internal resistances for each cell as much as possible. A 12V pack of 4 in series would be about 1.5 kWh. The higher the V the more impressive your mower is going to be but weight and space would need to be factored in. You can find weight and dimensions easily on google. I also have busbars and a bunch of EVpower BMS strips to prevent overvolting.

I'd be happy to sell cells at about $40 each with bits but I'd want to sell them in their pairs, otherwise I'd be left with a cell I can't do a lot with. For a mower I wouldn't bother with parallel pairs.

I also have a used one of these: http://www.motenergy.com/me1114.html (3 phase AC motor) that would be a perfect size for a ride on mower, but I don't have a controller for it and it may be out of the budget for this assignment - I'd want $400 for it, but thought I'd let you know anyway. Probably a DC motor will fit the budget of an assignment.

Workinkiwi
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Re: Help required with school assignment

Post by Workinkiwi » Fri, 26 Jan 2018, 15:43

Hi sorry been offline.
Currently we are trying to get a floor sweeper from we’re i work.
I might be keen on buying some batteries.
This is on hold until school is back as she needs to talk to her teacher.

Thanks everyone

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Re: Help required with school assignment

Post by coulomb » Sat, 27 Jan 2018, 08:25

alexeiw123 wrote:
Fri, 26 Jan 2018, 11:25
I've got a bunch (36x) of CALB SE130Ah cells in Port Macquarie...
Are you sure that they are 130 Ah?
What size are they?

I may be interested if you want to get rid of some. These would be for my solar energy system, which has CALB SE 160 Ah cells mostly, but a few ex-EV 100 Ah cells. Some of the latter are quite high internal resistance, and I'd like to replace them with better if possible.
Learning how to patch and repair PIP-4048 inverter-chargers and Elcon chargers.

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Re: Help required with school assignment

Post by alexeiw123 » Sat, 27 Jan 2018, 13:12

coulomb wrote:
Sat, 27 Jan 2018, 08:25
alexeiw123 wrote:
Fri, 26 Jan 2018, 11:25
I've got a bunch (36x) of CALB SE130Ah cells in Port Macquarie...
Are you sure that they are 130 Ah?
What size are they?
Definitely SE130AH - can't measure them now, my garage has limited space so they're packed up at my Dad's where there's more room and tools.

Here's a photo though of the 130 Ah coming out of the car, next to the ones that went in to it. You can take as many as you like. https://goo.gl/photos/7mEnqs8Mmnu2Znzq7

All cells were tested to work out internal resistance at 50% SoC (in late 2015). Of the 45 that came out, 9 were too high to be useful, the remaining 36 have been matched up to have parallel pairs with as similar internal resistance as possible. I've got all the working in a spreadsheet if you'd like to see values. 36 'good' cells range from 1.8 mΩ to 5.5 mΩ calculated IR at 50% SoC.

I'd be interested to hear how you have set up your home energy system. That was my intention with these but have decided I'm better off just getting more solar at this point in time.

I'm getting off topic a little now, so PM me if you want to discuss more.

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