I already have two electric mowers (long story): a Makita and an Ozito. On a pair of (18V 4aH) batteries I can get about 200m2 of grass cut if you do it regularly.  I've ended up getting five batteries for each mower (the Makita batteries are mostly for powertools as i prefer to use the Ozito for mowing) as the odd number means I can rotate the batteries so they don't stay as a permanent pair.  Get a dual charger if you can (both Makita and Ozito sell them, don't know about other brands).
Don't be fooled by manufacturers spruiking higher-voltage systems: amp-hours is what you want.

Amp.hours (Ah, not aH) mean nothing on their own.

Watt.hours (Wh) are actually what you should be looking for, because you don't need to interpret it by checking on the voltage.

Yyyyyyyyeeeeeesssssss.............

It does depend on exactly what one is trying to do.

To measure battery capacity used on a particular vehicle, its easier to think in Ah as, one, thats how most batteries have the capacity specified and two, its relatively easy to get a meter that will display the Ah's used, Which is a REALLY EXCELLENT way of seeing how much "fuel" on has left. Note: a lot of electrical assisted bikes and Mobility scooters use battery voltage for checking battery capacity, this from experience is useless, particularly with Lithium secondary cells which change little in Voltage for 80% of there capacity range.

woodford

Agree, but this (Ah) is typically only used on 12V car type battery systems. For almost everything else, especially power supply systems its kWh.

I already have two electric mowers (long story): a Makita and an Ozito. On a pair of (18V 4aH) batteries I can get about 200m2 of grass cut if you do it regularly.  I've ended up getting five batteries for each mower (the Makita batteries are mostly for powertools as i prefer to use the Ozito for mowing) as the odd number means I can rotate the batteries so they don't stay as a permanent pair.  Get a dual charger if you can (both Makita and Ozito sell them, don't know about other brands).
Don't be fooled by manufacturers spruiking higher-voltage systems: amp-hours is what you want.

Amp.hours (Ah, not aH) mean nothing on their own.

Watt.hours (Wh) are actually what you should be looking for, because you don't need to interpret it by checking on the voltage.

Yyyyyyyyeeeeeesssssss.............

It does depend on exactly what one is trying to do.

To measure battery capacity used on a particular vehicle, its easier to think in Ah as, one, thats how most batteries have the capacity specified and two, its relatively easy to get a meter that will display the Ah's used, Which is a REALLY EXCELLENT way of seeing how much "fuel" on has left. Note: a lot of electrical assisted bikes and Mobility scooters use battery voltage for checking battery capacity, this from experience is useless, particularly with Lithium secondary cells which change little in Voltage for 80% of there capacity range.

woodford

Agree, but this (Ah) is typically only used on 12V car type battery systems. For almost everything else, especially power supply systems its kWh.

A couple of points .............

When one is designing an electric vehicle its essential one knows the watt hour capacity of the batteries

When one though is operating said vehicle all one needs is a RELIABLE way of measuring capacity used, it does not matter at all how this is measured. For this Ah meters are readily avalible and cheap and one does not have to worry about battery voltage. For Ebikes and trikes one can get a Cycle Analayst, this will display a wide range of values, Ah's, watthours, voltage current, total number of battery cycles, regenerative braking power, etc. I usually leave it on the page that shows Ah/distance, power supplied to the motor and battery voltage.

woodford

There are 3 MAJOR problems when designing and operating Electric vehicles.........

1: Batterry capacity. Lithium Iron Phostphate batteries are still quite expensive and one never has enough capacity
THey ae though getting cheaper, but one needs to get  GOOD quality cells, there is plenty of rubbish out there.

2:Very high quality wiring, good routing and protection of the wiring and good quality connectors.

3: Its almost certain  the motors are over specified to hell, one needs to usually operate the motor at least at half the specified power so the the motor/wirng and controler do not get to hot. The chinese manufacturers of ebike hub motors usually spec the motors to operate up 120 degrees C, this is WAY to high for Australia.

On my trike I have set the maximum motor current to 60%, even then the controler will ocassionally shut down on a steep hill in very hot weather.

woodford

Amp.hours (Ah, not aH) mean nothing on their own.

Watt.hours (Wh) are actually what you should be looking for, because you don't need to interpret it by checking on the voltage.

In the case of both of my mowers, they are 36V (18V*2) setups, so the batteries are directly comparable by checking the Ah.  The Wh are not listed anywhere so to compare between different voltage systems you'll have to break out google.
EDIT: The bloke next door has a single-battery mower of some specification and it is a complete POS and can only cut about 50m2 of grass at a time, so I assume the battery capacity isn't great no matter what voltage it's running at.
There's probably a reason that manufacturers use the voltage as the headline marketing tactic... :

Whilst in Finland (Rovemini) two weeks ago we took a snow mobile ride through forest and across a frozen lake. The snow mobiles were electric supplied by a company still in R&D phase so basically they are test models.

Cannot remember all the specs, but I'm told they out accelerate petrol versions (power and speed limited for novices like me). They have a sled they pull for the kids if require no issue.  But certainly their strongest draw card is they are very very quiet. Amazing going along on 3 mobiles and I can talk quiet easily to my pillion passenger with a helmet on. Certainly the reindeer didn't run away.

The biggest benefit we didn't notice until a conventional snow mobile passed us, the exhaust smell! Could you imagine being 3 or more in a row of these petrol power things going through forest paths with no wind, like when we were out?

The downside
- Range, they are currently limited to 45km due to using a 10kWh battery. Newer battery technology will increase this but still not like a petrol snow mobile and not as easy to refuel. However for short runs, with a bigger battery up tp 100km range in future, its probably got a suitable market.

- Battery warmth, it was -15C, the batteries cannot be let get cold. So they bikes sit on a charger all the time, however the insulation and heat sinks they have around the battery keeps them warn for a number of hours off power and not in use. In use the heat from the power draw is enough to keep them warm even when stopping for a meal like we did.

Amp.hours (Ah, not aH) mean nothing on their own.

Watt.hours (Wh) are actually what you should be looking for, because you don't need to interpret it by checking on the voltage.

In the case of both of my mowers, they are 36V (18V*2) setups, so the batteries are directly comparable by checking the Ah.  The Wh are not listed anywhere so to compare between different voltage systems you'll have to break out google.
EDIT: The bloke next door has a single-battery mower of some specification and it is a complete POS and can only cut about 50m2 of grass at a time, so I assume the battery capacity isn't great no matter what voltage it's running at.
There's probably a reason that manufacturers use the voltage as the headline marketing tactic... :

The higher voltage units, like cordless drills tend to have more torque, but also it enables smaller wires and connectors and faster charging is their main benefit. Note some electric cars will likely come out with higher battery voltages to enable faster charging.

Single Battery just means its kWh storage is too small to cut more than 50m2 of grass, two batteries would just double that. If you only have 50m2 of grass or willing to do in stints, then it maybe fine for you. My home in Dubai has 18m2 of grass, so it would work for me, however my old acreage in Gladstone, breasts on bull would be more useful.

Good write-up here on VW's new MEB modular electric car platform.  Looks like it could be a winner if the price is right and charge times are quick:
https://jalopnik.com/the-fascinating-engineering-behind-vws-electric-car-pla-1829257860

The Irish are looking to ban the IC engine for new vehicles after 2030, and the rego of existing vehicles with IC engines after 2045.
https://www.caradvice.com.au/767557/ireland-petrol-diesel-ban/

I can imagine it might work in a small country like Ireland, but it would be total electoral suicide in Australia.

The Irish are looking to ban the IC engine for new vehicles after 2030, and the rego of existing vehicles with IC engines after 2045.
https://www.caradvice.com.au/767557/ireland-petrol-diesel-ban/

I can imagine it might work in a small country like Ireland, but it would be total electoral suicide in Australia.

The country is 500 x 250km in size,only marginally bigger than Tasmania, but much flatter. I can see it working there even with the Elect cars of today.

The country however still relies on burning coal and peat for much of its power and not long ago discovered oil.

The Irish are looking to ban the IC engine for new vehicles after 2030, and the rego of existing vehicles with IC engines after 2045.
https://www.caradvice.com.au/767557/ireland-petrol-diesel-ban/

I can imagine it might work in a small country like Ireland, but it would be total electoral suicide in Australia.

The country is 500 x 250km in size,only marginally bigger than Tasmania, but much flatter. I can see it working there even with the Elect cars of today.

The country however still relies on burning coal and peat for much of its power and not long ago discovered oil.

Yeah, a pretty useless place for generating electricity with Solar PV, but good for wind generation.  They're struggling to get anywhere near their Renewable targets at present...

The Irish are looking to ban the IC engine for new vehicles after 2030, and the rego of existing vehicles with IC engines after 2045.
https://www.caradvice.com.au/767557/ireland-petrol-diesel-ban/

I can imagine it might work in a small country like Ireland, but it would be total electoral suicide in Australia.

The country is 500 x 250km in size,only marginally bigger than Tasmania, but much flatter. I can see it working there even with the Elect cars of today.

The country however still relies on burning coal and peat for much of its power and not long ago discovered oil.

Yeah, a pretty useless place for generating electricity with Solar PV, but good for wind generation.  They're struggling to get anywhere near their Renewable targets at present...

Very large wind potential, but what to do when no wind? Thats alot of peaking gas to have as a backup.

They have existing coal and peat power stations that are various stages of mid life, so shutting them down is basically pi$$ing money against the wall. Very limited hydro capacity.

They have a HV connector to the UK, don't know the size but you can be assured its of basically peaking capacity or simillar. They have connected the Nth and Irish grids in recent years and now under one authority.

Also their trains are still mostly diesel.

RTT, torque in an electric motor is proportional to current, there is no relation to voltage.

To make a battery for more torque you need bigger cells, not more cells (higher voltage). This is why cars that need a higher CCA battery get physically larger, but not higher in voltage.

Hi Aaron,
Not sure what you are replying too?

Unless the car is a city runaround that will never exceed it's range, I think the end of the internal combustion will be when  a car can go from Melbourne to Brisbane, and stop to "refuel" in the same time it takes to fill  a petrol tank.

anyone for a single rail shoe system for long drives

Regards,
David Head

Since cars are made overseas and given our small market, it will be take what we give you. We may just have to adjust to the 30-minute coffee break every 500 km or so.

Since cars are made overseas and given our small market, it will be take what we give you. We may just have to adjust to the 30-minute coffee break every 500 km or so.

Even if we did make cars still, we made 5 models and imported nearly 200 others.

I think if you can do 500km on a tank and need to wait 30min to recharge for another 500km, you pretty much have nailed it. My Diesel Ranger can do 1000km at Australian road speeds (800km in Dubai) on a tank. No way in hell I would be able to drive that from tank refill to refill without at least 30min of breaks in between. Hell, even the 5min family pee break (assuming none are girls and no one is having a No.2 will get you another 100km of range.

Back to Ireland
Irelands biggest challenge to the OT post is tha ~100GWh of electricity that needs to be found every day to run those EV cars, basically double what they generate today.

Since cars are made overseas and given our small market, it will be take what we give you. We may just have to adjust to the 30-minute coffee break every 500 km or so.

Which also happens to roughly align with the whole driver reviver thing as well.

Unless the car is a city runaround that will never exceed it's range, I think the end of the internal combustion will be when  a car can go from Melbourne to Brisbane, and stop to "refuel" in the same time it takes to fill  a petrol tank.

anyone for a single rail shoe system for long drives

Regards,
David Head

The best ones on offer now can probably do the trip with 2 recharges, maybe 3 if you consider they recharge to 80-85% quickly and rest painfully slow. So maybe factor in another 3h which I think if the recharges were targetted for the usual meal stops and pee stops may just take a similar time.

You, above, where you wrote something like ‘higher voltage units like cordless drills have more torque’ - that is not actually true. Torque is proportional to current.

The increased torque you see in new tools with higher voltages (the higher voltage is basically a marketing ploy) comes from them generally being ‘brushless’ which means that massive currents can be flown into the windings.

You, above, where you wrote something like ‘higher voltage units like cordless drills have more torque’ - that is not actually true. Torque is proportional to current.

The increased torque you see in new tools with higher voltages (the higher voltage is basically a marketing ploy) comes from them generally being ‘brushless’ which means that massive currents can be flown into the windings.

Mmm, not this year, you must have found an old post.

Point taken though.

Postscript:

Postscript:

I'm thinking there will be an business opportunity to provide road side recharge for EV's that run out of juice.

RACV, NRMA et al:
https://www.racv.com.au/on-the-road/roadside-assistance/roadside-care.html

RACV, NRMA et al:
https://www.racv.com.au/on-the-road/roadside-assistance/roadside-care.html

Yes agree, but do they yet or will they provide a road side fast recharge option for EV's?

Postscript:

Looking at that Generator, 60min of charge time might get them around 40km. Wiki says i3 consumes around 200W/km.